Merge pull request #198 from tendermint/release/v0.8.1

Release/v0.8.1

CHANGELOG.md

@@ -1,5 +1,37 @@
 # Changelog
 
+## 0.8.1 (April 5th, 2018)
+
+FEATURES:
+
+ - [common] Error.Error() includes cause
+ - [common] IsEmpty() for 0 length
+
+## 0.8.0 (April 4th, 2018)
+
+BREAKING:
+
+ - [merkle] `PutVarint->PutUvarint` in encodeByteSlice
+ - [db] batch.WriteSync()
+ - [common] Refactored and fixed `Parallel` function
+ - [common] Refactored `Rand` functionality
+ - [common] Remove unused `Right/LeftPadString` functions
+ - [common] Remove StackError, introduce Error interface (to replace use of pkg/errors)
+
+FEATURES:
+
+ - [db] NewPrefixDB for a DB with all keys prefixed
+ - [db] NewDebugDB prints everything during operation
+ - [common] SplitAndTrim func
+ - [common] rand.Float64(), rand.Int63n(n), rand.Int31n(n) and global equivalents
+ - [common] HexBytes Format()
+
+BUG FIXES:
+
+ - [pubsub] Fix unsubscribing
+ - [cli] Return config errors
+ - [common] Fix WriteFileAtomic Windows bug
+
 ## 0.7.1 (March 22, 2018)
 
 IMPROVEMENTS:

autofile/autofile.go

@@ -5,7 +5,7 @@ import (
 	"sync"
 	"time"
 
-	. "github.com/tendermint/tmlibs/common"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 /* AutoFile usage
@@ -44,7 +44,7 @@ type AutoFile struct {
 
 func OpenAutoFile(path string) (af *AutoFile, err error) {
 	af = &AutoFile{
-		ID:     RandStr(12) + ":" + path,
+		ID:     cmn.RandStr(12) + ":" + path,
 		Path:   path,
 		ticker: time.NewTicker(autoFileOpenDuration),
 	}
@@ -129,9 +129,8 @@ func (af *AutoFile) Size() (int64, error) {
 		if err != nil {
 			if err == os.ErrNotExist {
 				return 0, nil
-			} else {
-				return -1, err
 			}
+			return -1, err
 		}
 	}
 	stat, err := af.file.Stat()

autofile/group.go

@@ -15,7 +15,7 @@ import (
 	"sync"
 	"time"
 
-	. "github.com/tendermint/tmlibs/common"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 const (
@@ -54,7 +54,7 @@ The Group can also be used to binary-search for some line,
 assuming that marker lines are written occasionally.
 */
 type Group struct {
-	BaseService
+	cmn.BaseService
 
 	ID             string
 	Head           *AutoFile // The head AutoFile to write to
@@ -90,7 +90,7 @@ func OpenGroup(headPath string) (g *Group, err error) {
 		minIndex:       0,
 		maxIndex:       0,
 	}
-	g.BaseService = *NewBaseService(nil, "Group", g)
+	g.BaseService = *cmn.NewBaseService(nil, "Group", g)
 
 	gInfo := g.readGroupInfo()
 	g.minIndex = gInfo.MinIndex
@@ -267,7 +267,7 @@ func (g *Group) RotateFile() {
 		panic(err)
 	}
 
-	g.maxIndex += 1
+	g.maxIndex++
 }
 
 // NewReader returns a new group reader.
@@ -277,9 +277,8 @@ func (g *Group) NewReader(index int) (*GroupReader, error) {
 	err := r.SetIndex(index)
 	if err != nil {
 		return nil, err
-	} else {
-		return r, nil
 	}
+	return r, nil
 }
 
 // Returns -1 if line comes after, 0 if found, 1 if line comes before.
@@ -311,9 +310,8 @@ func (g *Group) Search(prefix string, cmp SearchFunc) (*GroupReader, bool, error
 			if err != nil {
 				r.Close()
 				return nil, false, err
-			} else {
-				return r, match, err
 			}
+			return r, match, err
 		}
 
 		// Read starting roughly at the middle file,
@@ -349,9 +347,8 @@ func (g *Group) Search(prefix string, cmp SearchFunc) (*GroupReader, bool, error
 			if err != nil {
 				r.Close()
 				return nil, false, err
-			} else {
-				return r, true, err
 			}
+			return r, true, err
 		} else {
 			// We passed it
 			maxIndex = curIndex - 1
@@ -429,9 +426,8 @@ GROUP_LOOP:
 			if err == io.EOF {
 				if found {
 					return match, found, nil
-				} else {
-					continue GROUP_LOOP
 				}
+				continue GROUP_LOOP
 			} else if err != nil {
 				return "", false, err
 			}
@@ -442,9 +438,8 @@ GROUP_LOOP:
 			if r.CurIndex() > i {
 				if found {
 					return match, found, nil
-				} else {
-					continue GROUP_LOOP
 				}
+				continue GROUP_LOOP
 			}
 		}
 	}
@@ -520,7 +515,7 @@ func (g *Group) readGroupInfo() GroupInfo {
 		minIndex, maxIndex = 0, 0
 	} else {
 		// Otherwise, the head file is 1 greater
-		maxIndex += 1
+		maxIndex++
 	}
 	return GroupInfo{minIndex, maxIndex, totalSize, headSize}
 }
@@ -528,9 +523,8 @@ func (g *Group) readGroupInfo() GroupInfo {
 func filePathForIndex(headPath string, index int, maxIndex int) string {
 	if index == maxIndex {
 		return headPath
-	} else {
-		return fmt.Sprintf("%v.%03d", headPath, index)
 	}
+	return fmt.Sprintf("%v.%03d", headPath, index)
 }
 
 //--------------------------------------------------------------------------------
@@ -567,9 +561,8 @@ func (gr *GroupReader) Close() error {
 		gr.curFile = nil
 		gr.curLine = nil
 		return err
-	} else {
-		return nil
 	}
+	return nil
 }
 
 // Read implements io.Reader, reading bytes from the current Reader
@@ -598,10 +591,10 @@ func (gr *GroupReader) Read(p []byte) (n int, err error) {
 		if err == io.EOF {
 			if n >= lenP {
 				return n, nil
-			} else { // Open the next file
-				if err1 := gr.openFile(gr.curIndex + 1); err1 != nil {
-					return n, err1
-				}
+			}
+			// Open the next file
+			if err1 := gr.openFile(gr.curIndex + 1); err1 != nil {
+				return n, err1
 			}
 		} else if err != nil {
 			return n, err
@@ -643,10 +636,9 @@ func (gr *GroupReader) ReadLine() (string, error) {
 			}
 			if len(bytesRead) > 0 && bytesRead[len(bytesRead)-1] == byte('\n') {
 				return linePrefix + string(bytesRead[:len(bytesRead)-1]), nil
-			} else {
-				linePrefix += string(bytesRead)
-				continue
 			}
+			linePrefix += string(bytesRead)
+			continue
 		} else if err != nil {
 			return "", err
 		}
@@ -726,11 +718,11 @@ func (gr *GroupReader) SetIndex(index int) error {
 func MakeSimpleSearchFunc(prefix string, target int) SearchFunc {
 	return func(line string) (int, error) {
 		if !strings.HasPrefix(line, prefix) {
-			return -1, errors.New(Fmt("Marker line did not have prefix: %v", prefix))
+			return -1, errors.New(cmn.Fmt("Marker line did not have prefix: %v", prefix))
 		}
 		i, err := strconv.Atoi(line[len(prefix):])
 		if err != nil {
-			return -1, errors.New(Fmt("Failed to parse marker line: %v", err.Error()))
+			return -1, errors.New(cmn.Fmt("Failed to parse marker line: %v", err.Error()))
 		}
 		if target < i {
 			return 1, nil

autofile/group_test.go

@@ -175,7 +175,7 @@ func TestSearch(t *testing.T) {
 			if !strings.HasPrefix(line, fmt.Sprintf("INFO %v ", cur)) {
 				t.Fatalf("Unexpected INFO #. Expected %v got:\n%v", cur, line)
 			}
-			cur += 1
+			cur++
 		}
 		gr.Close()
 	}

cli/setup.go

@@ -139,9 +139,8 @@ func bindFlagsLoadViper(cmd *cobra.Command, args []string) error {
 		// stderr, so if we redirect output to json file, this doesn't appear
 		// fmt.Fprintln(os.Stderr, "Using config file:", viper.ConfigFileUsed())
 	} else if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
-		// we ignore not found error, only parse error
-		// stderr, so if we redirect output to json file, this doesn't appear
-		fmt.Fprintf(os.Stderr, "%#v", err)
+		// ignore not found error, return other errors
+		return err
 	}
 	return nil
 }

clist/clist.go

@@ -316,7 +316,7 @@ func (l *CList) PushBack(v interface{}) *CElement {
 		l.wg.Done()
 		close(l.waitCh)
 	}
-	l.len += 1
+	l.len++
 
 	// Modify the tail
 	if l.tail == nil {
@@ -357,7 +357,7 @@ func (l *CList) Remove(e *CElement) interface{} {
 	}
 
 	// Update l.len
-	l.len -= 1
+	l.len--
 
 	// Connect next/prev and set head/tail
 	if prev == nil {

clist/clist_test.go

@@ -122,7 +122,7 @@ func _TestGCRandom(t *testing.T) {
 		v.Int = i
 		l.PushBack(v)
 		runtime.SetFinalizer(v, func(v *value) {
-			gcCount += 1
+			gcCount++
 		})
 	}
 
@@ -177,10 +177,10 @@ func TestScanRightDeleteRandom(t *testing.T) {
 				}
 				if el == nil {
 					el = l.FrontWait()
-					restartCounter += 1
+					restartCounter++
 				}
 				el = el.Next()
-				counter += 1
+				counter++
 			}
 			fmt.Printf("Scanner %v restartCounter: %v counter: %v\n", scannerID, restartCounter, counter)
 		}(i)

common/async.go

@@ -1,15 +1,148 @@
 package common
 
-import "sync"
-
-func Parallel(tasks ...func()) {
-	var wg sync.WaitGroup
-	wg.Add(len(tasks))
-	for _, task := range tasks {
-		go func(task func()) {
-			task()
-			wg.Done()
-		}(task)
-	}
-	wg.Wait()
+import (
+	"sync/atomic"
+)
+
+//----------------------------------------
+// Task
+
+// val: the value returned after task execution.
+// err: the error returned during task completion.
+// abort: tells Parallel to return, whether or not all tasks have completed.
+type Task func(i int) (val interface{}, err error, abort bool)
+
+type TaskResult struct {
+	Value interface{}
+	Error error
+}
+
+type TaskResultCh <-chan TaskResult
+
+type taskResultOK struct {
+	TaskResult
+	OK bool
+}
+
+type TaskResultSet struct {
+	chz     []TaskResultCh
+	results []taskResultOK
+}
+
+func newTaskResultSet(chz []TaskResultCh) *TaskResultSet {
+	return &TaskResultSet{
+		chz:     chz,
+		results: nil,
+	}
+}
+
+func (trs *TaskResultSet) Channels() []TaskResultCh {
+	return trs.chz
+}
+
+func (trs *TaskResultSet) LatestResult(index int) (TaskResult, bool) {
+	if len(trs.results) <= index {
+		return TaskResult{}, false
+	}
+	resultOK := trs.results[index]
+	return resultOK.TaskResult, resultOK.OK
+}
+
+// NOTE: Not concurrency safe.
+func (trs *TaskResultSet) Reap() *TaskResultSet {
+	if trs.results == nil {
+		trs.results = make([]taskResultOK, len(trs.chz))
+	}
+	for i := 0; i < len(trs.results); i++ {
+		var trch = trs.chz[i]
+		select {
+		case result := <-trch:
+			// Overwrite result.
+			trs.results[i] = taskResultOK{
+				TaskResult: result,
+				OK:         true,
+			}
+		default:
+			// Do nothing.
+		}
+	}
+	return trs
+}
+
+// Returns the firstmost (by task index) error as
+// discovered by all previous Reap() calls.
+func (trs *TaskResultSet) FirstValue() interface{} {
+	for _, result := range trs.results {
+		if result.Value != nil {
+			return result.Value
+		}
+	}
+	return nil
+}
+
+// Returns the firstmost (by task index) error as
+// discovered by all previous Reap() calls.
+func (trs *TaskResultSet) FirstError() error {
+	for _, result := range trs.results {
+		if result.Error != nil {
+			return result.Error
+		}
+	}
+	return nil
+}
+
+//----------------------------------------
+// Parallel
+
+// Run tasks in parallel, with ability to abort early.
+// Returns ok=false iff any of the tasks returned abort=true.
+// NOTE: Do not implement quit features here.  Instead, provide convenient
+// concurrent quit-like primitives, passed implicitly via Task closures. (e.g.
+// it's not Parallel's concern how you quit/abort your tasks).
+func Parallel(tasks ...Task) (trs *TaskResultSet, ok bool) {
+	var taskResultChz = make([]TaskResultCh, len(tasks)) // To return.
+	var taskDoneCh = make(chan bool, len(tasks))         // A "wait group" channel, early abort if any true received.
+	var numPanics = new(int32)                           // Keep track of panics to set ok=false later.
+	ok = true                                            // We will set it to false iff any tasks panic'd or returned abort.
+
+	// Start all tasks in parallel in separate goroutines.
+	// When the task is complete, it will appear in the
+	// respective taskResultCh (associated by task index).
+	for i, task := range tasks {
+		var taskResultCh = make(chan TaskResult, 1) // Capacity for 1 result.
+		taskResultChz[i] = taskResultCh
+		go func(i int, task Task, taskResultCh chan TaskResult) {
+			// Recovery
+			defer func() {
+				if pnk := recover(); pnk != nil {
+					atomic.AddInt32(numPanics, 1)
+					taskResultCh <- TaskResult{nil, ErrorWrap(pnk, "Panic in task")}
+					taskDoneCh <- false
+				}
+			}()
+			// Run the task.
+			var val, err, abort = task(i)
+			// Send val/err to taskResultCh.
+			// NOTE: Below this line, nothing must panic/
+			taskResultCh <- TaskResult{val, err}
+			// Decrement waitgroup.
+			taskDoneCh <- abort
+		}(i, task, taskResultCh)
+	}
+
+	// Wait until all tasks are done, or until abort.
+	// DONE_LOOP:
+	for i := 0; i < len(tasks); i++ {
+		abort := <-taskDoneCh
+		if abort {
+			ok = false
+			break
+		}
+	}
+
+	// Ok is also false if there were any panics.
+	// We must do this check here (after DONE_LOOP).
+	ok = ok && (atomic.LoadInt32(numPanics) == 0)
+
+	return newTaskResultSet(taskResultChz).Reap(), ok
 }

common/async_test.go

@@ -0,0 +1,152 @@
+package common
+
+import (
+	"errors"
+	"fmt"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParallel(t *testing.T) {
+
+	// Create tasks.
+	var counter = new(int32)
+	var tasks = make([]Task, 100*1000)
+	for i := 0; i < len(tasks); i++ {
+		tasks[i] = func(i int) (res interface{}, err error, abort bool) {
+			atomic.AddInt32(counter, 1)
+			return -1 * i, nil, false
+		}
+	}
+
+	// Run in parallel.
+	var trs, ok = Parallel(tasks...)
+	assert.True(t, ok)
+
+	// Verify.
+	assert.Equal(t, int(*counter), len(tasks), "Each task should have incremented the counter already")
+	var failedTasks int
+	for i := 0; i < len(tasks); i++ {
+		taskResult, ok := trs.LatestResult(i)
+		if !ok {
+			assert.Fail(t, "Task #%v did not complete.", i)
+			failedTasks++
+		} else if taskResult.Error != nil {
+			assert.Fail(t, "Task should not have errored but got %v", taskResult.Error)
+			failedTasks++
+		} else if !assert.Equal(t, -1*i, taskResult.Value.(int)) {
+			assert.Fail(t, "Task should have returned %v but got %v", -1*i, taskResult.Value.(int))
+			failedTasks++
+		} else {
+			// Good!
+		}
+	}
+	assert.Equal(t, failedTasks, 0, "No task should have failed")
+	assert.Nil(t, trs.FirstError(), "There should be no errors")
+	assert.Equal(t, 0, trs.FirstValue(), "First value should be 0")
+}
+
+func TestParallelAbort(t *testing.T) {
+
+	var flow1 = make(chan struct{}, 1)
+	var flow2 = make(chan struct{}, 1)
+	var flow3 = make(chan struct{}, 1) // Cap must be > 0 to prevent blocking.
+	var flow4 = make(chan struct{}, 1)
+
+	// Create tasks.
+	var tasks = []Task{
+		func(i int) (res interface{}, err error, abort bool) {
+			assert.Equal(t, i, 0)
+			flow1 <- struct{}{}
+			return 0, nil, false
+		},
+		func(i int) (res interface{}, err error, abort bool) {
+			assert.Equal(t, i, 1)
+			flow2 <- <-flow1
+			return 1, errors.New("some error"), false
+		},
+		func(i int) (res interface{}, err error, abort bool) {
+			assert.Equal(t, i, 2)
+			flow3 <- <-flow2
+			return 2, nil, true
+		},
+		func(i int) (res interface{}, err error, abort bool) {
+			assert.Equal(t, i, 3)
+			<-flow4
+			return 3, nil, false
+		},
+	}
+
+	// Run in parallel.
+	var taskResultSet, ok = Parallel(tasks...)
+	assert.False(t, ok, "ok should be false since we aborted task #2.")
+
+	// Verify task #3.
+	// Initially taskResultSet.chz[3] sends nothing since flow4 didn't send.
+	waitTimeout(t, taskResultSet.chz[3], "Task #3")
+
+	// Now let the last task (#3) complete after abort.
+	flow4 <- <-flow3
+
+	// Verify task #0, #1, #2.
+	checkResult(t, taskResultSet, 0, 0, nil, nil)
+	checkResult(t, taskResultSet, 1, 1, errors.New("some error"), nil)
+	checkResult(t, taskResultSet, 2, 2, nil, nil)
+}
+
+func TestParallelRecover(t *testing.T) {
+
+	// Create tasks.
+	var tasks = []Task{
+		func(i int) (res interface{}, err error, abort bool) {
+			return 0, nil, false
+		},
+		func(i int) (res interface{}, err error, abort bool) {
+			return 1, errors.New("some error"), false
+		},
+		func(i int) (res interface{}, err error, abort bool) {
+			panic(2)
+		},
+	}
+
+	// Run in parallel.
+	var taskResultSet, ok = Parallel(tasks...)
+	assert.False(t, ok, "ok should be false since we panic'd in task #2.")
+
+	// Verify task #0, #1, #2.
+	checkResult(t, taskResultSet, 0, 0, nil, nil)
+	checkResult(t, taskResultSet, 1, 1, errors.New("some error"), nil)
+	checkResult(t, taskResultSet, 2, nil, nil, 2)
+}
+
+// Wait for result
+func checkResult(t *testing.T, taskResultSet *TaskResultSet, index int, val interface{}, err error, pnk interface{}) {
+	taskResult, ok := taskResultSet.LatestResult(index)
+	taskName := fmt.Sprintf("Task #%v", index)
+	assert.True(t, ok, "TaskResultCh unexpectedly closed for %v", taskName)
+	assert.Equal(t, val, taskResult.Value, taskName)
+	if err != nil {
+		assert.Equal(t, err, taskResult.Error, taskName)
+	} else if pnk != nil {
+		assert.Equal(t, pnk, taskResult.Error.(Error).Cause(), taskName)
+	} else {
+		assert.Nil(t, taskResult.Error, taskName)
+	}
+}
+
+// Wait for timeout (no result)
+func waitTimeout(t *testing.T, taskResultCh TaskResultCh, taskName string) {
+	select {
+	case _, ok := <-taskResultCh:
+		if !ok {
+			assert.Fail(t, "TaskResultCh unexpectedly closed (%v)", taskName)
+		} else {
+			assert.Fail(t, "TaskResultCh unexpectedly returned for %v", taskName)
+		}
+	case <-time.After(1 * time.Second): // TODO use deterministic time?
+		// Good!
+	}
+}

common/bit_array.go

@@ -168,9 +168,8 @@ func (bA *BitArray) Sub(o *BitArray) *BitArray {
 			}
 		}
 		return c
-	} else {
-		return bA.and(o.Not()) // Note degenerate case where o == nil
 	}
+	return bA.and(o.Not()) // Note degenerate case where o == nil
 }
 
 func (bA *BitArray) IsEmpty() bool {

common/bytes.go

@@ -51,3 +51,12 @@ func (bz HexBytes) Bytes() []byte {
 func (bz HexBytes) String() string {
 	return strings.ToUpper(hex.EncodeToString(bz))
 }
+
+func (bz HexBytes) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'p':
+		s.Write([]byte(fmt.Sprintf("%p", bz)))
+	default:
+		s.Write([]byte(fmt.Sprintf("%X", []byte(bz))))
+	}
+}

common/colors.go

@@ -38,9 +38,8 @@ const (
 func treat(s string, color string) string {
 	if len(s) > 2 && s[:2] == "\x1b[" {
 		return s
-	} else {
-		return color + s + ANSIReset
 	}
+	return color + s + ANSIReset
 }
 
 func treatAll(color string, args ...interface{}) string {

common/errors.go

@@ -2,23 +2,239 @@ package common
 
 import (
 	"fmt"
+	"runtime"
 )
 
-type StackError struct {
-	Err   interface{}
-	Stack []byte
+//----------------------------------------
+// Convenience methods
+
+// ErrorWrap will just call .TraceFrom(), or create a new *cmnError.
+func ErrorWrap(cause interface{}, format string, args ...interface{}) Error {
+	msg := Fmt(format, args...)
+	if causeCmnError, ok := cause.(*cmnError); ok {
+		return causeCmnError.TraceFrom(1, msg)
+	}
+	// NOTE: cause may be nil.
+	// NOTE: do not use causeCmnError here, not the same as nil.
+	return newError(msg, cause, cause).Stacktrace()
+}
+
+//----------------------------------------
+// Error & cmnError
+
+/*
+Usage:
+
+```go
+	// Error construction
+	var someT = errors.New("Some err type")
+	var err1 error = NewErrorWithT(someT, "my message")
+	...
+	// Wrapping
+	var err2 error  = ErrorWrap(err1, "another message")
+	if (err1 != err2) { panic("should be the same")
+	...
+	// Error handling
+	switch err2.T() {
+		case someT: ...
+	    default: ...
+	}
+```
+
+*/
+type Error interface {
+	Error() string
+	Message() string
+	Stacktrace() Error
+	Trace(format string, args ...interface{}) Error
+	TraceFrom(offset int, format string, args ...interface{}) Error
+	Cause() interface{}
+	WithT(t interface{}) Error
+	T() interface{}
+	Format(s fmt.State, verb rune)
+}
+
+// New Error with no cause where the type is the format string of the message..
+func NewError(format string, args ...interface{}) Error {
+	msg := Fmt(format, args...)
+	return newError(msg, nil, format)
+
+}
+
+// New Error with specified type and message.
+func NewErrorWithT(t interface{}, format string, args ...interface{}) Error {
+	msg := Fmt(format, args...)
+	return newError(msg, nil, t)
+}
+
+// NOTE: The name of a function "NewErrorWithCause()" implies that you are
+// creating a new Error, yet, if the cause is an Error, creating a new Error to
+// hold a ref to the old Error is probably *not* what you want to do.
+// So, use ErrorWrap(cause, format, a...) instead, which returns the same error
+// if cause is an Error.
+// IF you must set an Error as the cause of an Error,
+// then you can use the WithCauser interface to do so manually.
+// e.g. (error).(tmlibs.WithCauser).WithCause(causeError)
+
+type WithCauser interface {
+	WithCause(cause interface{}) Error
+}
+
+type cmnError struct {
+	msg        string         // first msg which also appears in msg
+	cause      interface{}    // underlying cause (or panic object)
+	t          interface{}    // for switching on error
+	msgtraces  []msgtraceItem // all messages traced
+	stacktrace []uintptr      // first stack trace
+}
+
+var _ WithCauser = &cmnError{}
+var _ Error = &cmnError{}
+
+// NOTE: do not expose.
+func newError(msg string, cause interface{}, t interface{}) *cmnError {
+	return &cmnError{
+		msg:        msg,
+		cause:      cause,
+		t:          t,
+		msgtraces:  nil,
+		stacktrace: nil,
+	}
+}
+
+func (err *cmnError) Message() string {
+	return err.msg
+}
+
+func (err *cmnError) Error() string {
+	return fmt.Sprintf("%v", err)
 }
 
-func (se StackError) String() string {
-	return fmt.Sprintf("Error: %v\nStack: %s", se.Err, se.Stack)
+// Captures a stacktrace if one was not already captured.
+func (err *cmnError) Stacktrace() Error {
+	if err.stacktrace == nil {
+		var offset = 3
+		var depth = 32
+		err.stacktrace = captureStacktrace(offset, depth)
+	}
+	return err
 }
 
-func (se StackError) Error() string {
-	return se.String()
+// Add tracing information with msg.
+func (err *cmnError) Trace(format string, args ...interface{}) Error {
+	msg := Fmt(format, args...)
+	return err.doTrace(msg, 0)
 }
 
-//--------------------------------------------------------------------------------------------------
-// panic wrappers
+// Same as Trace, but traces the line `offset` calls out.
+// If n == 0, the behavior is identical to Trace().
+func (err *cmnError) TraceFrom(offset int, format string, args ...interface{}) Error {
+	msg := Fmt(format, args...)
+	return err.doTrace(msg, offset)
+}
+
+// Return last known cause.
+// NOTE: The meaning of "cause" is left for the caller to define.
+// There exists no "canonical" definition of "cause".
+// Instead of blaming, try to handle it, or organize it.
+func (err *cmnError) Cause() interface{} {
+	return err.cause
+}
+
+// Overwrites the Error's cause.
+func (err *cmnError) WithCause(cause interface{}) Error {
+	err.cause = cause
+	return err
+}
+
+// Overwrites the Error's type.
+func (err *cmnError) WithT(t interface{}) Error {
+	err.t = t
+	return err
+}
+
+// Return the "type" of this message, primarily for switching
+// to handle this Error.
+func (err *cmnError) T() interface{} {
+	return err.t
+}
+
+func (err *cmnError) doTrace(msg string, n int) Error {
+	pc, _, _, _ := runtime.Caller(n + 2) // +1 for doTrace().  +1 for the caller.
+	// Include file & line number & msg.
+	// Do not include the whole stack trace.
+	err.msgtraces = append(err.msgtraces, msgtraceItem{
+		pc:  pc,
+		msg: msg,
+	})
+	return err
+}
+
+func (err *cmnError) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'p':
+		s.Write([]byte(fmt.Sprintf("%p", &err)))
+	default:
+		if s.Flag('#') {
+			s.Write([]byte("--= Error =--\n"))
+			// Write msg.
+			s.Write([]byte(fmt.Sprintf("Message: %#s\n", err.msg)))
+			// Write cause.
+			s.Write([]byte(fmt.Sprintf("Cause: %#v\n", err.cause)))
+			// Write type.
+			s.Write([]byte(fmt.Sprintf("T: %#v\n", err.t)))
+			// Write msg trace items.
+			s.Write([]byte(fmt.Sprintf("Msg Traces:\n")))
+			for i, msgtrace := range err.msgtraces {
+				s.Write([]byte(fmt.Sprintf(" %4d  %s\n", i, msgtrace.String())))
+			}
+			// Write stack trace.
+			if err.stacktrace != nil {
+				s.Write([]byte(fmt.Sprintf("Stack Trace:\n")))
+				for i, pc := range err.stacktrace {
+					fnc := runtime.FuncForPC(pc)
+					file, line := fnc.FileLine(pc)
+					s.Write([]byte(fmt.Sprintf(" %4d  %s:%d\n", i, file, line)))
+				}
+			}
+			s.Write([]byte("--= /Error =--\n"))
+		} else {
+			// Write msg.
+			if err.cause != nil {
+				s.Write([]byte(fmt.Sprintf("Error{`%s` (cause: %v)}", err.msg, err.cause))) // TODO tick-esc?
+			} else {
+				s.Write([]byte(fmt.Sprintf("Error{`%s`}", err.msg))) // TODO tick-esc?
+			}
+		}
+	}
+}
+
+//----------------------------------------
+// stacktrace & msgtraceItem
+
+func captureStacktrace(offset int, depth int) []uintptr {
+	var pcs = make([]uintptr, depth)
+	n := runtime.Callers(offset, pcs)
+	return pcs[0:n]
+}
+
+type msgtraceItem struct {
+	pc  uintptr
+	msg string
+}
+
+func (mti msgtraceItem) String() string {
+	fnc := runtime.FuncForPC(mti.pc)
+	file, line := fnc.FileLine(mti.pc)
+	return fmt.Sprintf("%s:%d - %s",
+		file, line,
+		mti.msg,
+	)
+}
+
+//----------------------------------------
+// Panic wrappers
+// XXX DEPRECATED
 
 // A panic resulting from a sanity check means there is a programmer error
 // and some guarantee is not satisfied.

common/errors_test.go

@@ -0,0 +1,107 @@
+package common
+
+import (
+	fmt "fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestErrorPanic(t *testing.T) {
+	type pnk struct {
+		msg string
+	}
+
+	capturePanic := func() (err Error) {
+		defer func() {
+			if r := recover(); r != nil {
+				err = ErrorWrap(r, "This is the message in ErrorWrap(r, message).")
+			}
+			return
+		}()
+		panic(pnk{"something"})
+		return nil
+	}
+
+	var err = capturePanic()
+
+	assert.Equal(t, pnk{"something"}, err.Cause())
+	assert.Equal(t, pnk{"something"}, err.T())
+	assert.Equal(t, "This is the message in ErrorWrap(r, message).", err.Message())
+	assert.Equal(t, "Error{`This is the message in ErrorWrap(r, message).` (cause: {something})}", fmt.Sprintf("%v", err))
+	assert.Contains(t, fmt.Sprintf("%#v", err), "Message: This is the message in ErrorWrap(r, message).")
+	assert.Contains(t, fmt.Sprintf("%#v", err), "Stack Trace:\n    0")
+}
+
+func TestErrorWrapSomething(t *testing.T) {
+
+	var err = ErrorWrap("something", "formatter%v%v", 0, 1)
+
+	assert.Equal(t, "something", err.Cause())
+	assert.Equal(t, "something", err.T())
+	assert.Equal(t, "formatter01", err.Message())
+	assert.Equal(t, "Error{`formatter01` (cause: something)}", fmt.Sprintf("%v", err))
+	assert.Regexp(t, `Message: formatter01\n`, fmt.Sprintf("%#v", err))
+	assert.Contains(t, fmt.Sprintf("%#v", err), "Stack Trace:\n    0")
+}
+
+func TestErrorWrapNothing(t *testing.T) {
+
+	var err = ErrorWrap(nil, "formatter%v%v", 0, 1)
+
+	assert.Equal(t, nil, err.Cause())
+	assert.Equal(t, nil, err.T())
+	assert.Equal(t, "formatter01", err.Message())
+	assert.Equal(t, "Error{`formatter01`}", fmt.Sprintf("%v", err))
+	assert.Regexp(t, `Message: formatter01\n`, fmt.Sprintf("%#v", err))
+	assert.Contains(t, fmt.Sprintf("%#v", err), "Stack Trace:\n    0")
+}
+
+func TestErrorNewError(t *testing.T) {
+
+	var err = NewError("formatter%v%v", 0, 1)
+
+	assert.Equal(t, nil, err.Cause())
+	assert.Equal(t, "formatter%v%v", err.T())
+	assert.Equal(t, "formatter01", err.Message())
+	assert.Equal(t, "Error{`formatter01`}", fmt.Sprintf("%v", err))
+	assert.Regexp(t, `Message: formatter01\n`, fmt.Sprintf("%#v", err))
+	assert.NotContains(t, fmt.Sprintf("%#v", err), "Stack Trace")
+}
+
+func TestErrorNewErrorWithStacktrace(t *testing.T) {
+
+	var err = NewError("formatter%v%v", 0, 1).Stacktrace()
+
+	assert.Equal(t, nil, err.Cause())
+	assert.Equal(t, "formatter%v%v", err.T())
+	assert.Equal(t, "formatter01", err.Message())
+	assert.Equal(t, "Error{`formatter01`}", fmt.Sprintf("%v", err))
+	assert.Regexp(t, `Message: formatter01\n`, fmt.Sprintf("%#v", err))
+	assert.Contains(t, fmt.Sprintf("%#v", err), "Stack Trace:\n    0")
+}
+
+func TestErrorNewErrorWithTrace(t *testing.T) {
+
+	var err = NewError("formatter%v%v", 0, 1)
+	err.Trace("trace %v", 1)
+	err.Trace("trace %v", 2)
+	err.Trace("trace %v", 3)
+
+	assert.Equal(t, nil, err.Cause())
+	assert.Equal(t, "formatter%v%v", err.T())
+	assert.Equal(t, "formatter01", err.Message())
+	assert.Equal(t, "Error{`formatter01`}", fmt.Sprintf("%v", err))
+	assert.Regexp(t, `Message: formatter01\n`, fmt.Sprintf("%#v", err))
+	dump := fmt.Sprintf("%#v", err)
+	assert.NotContains(t, dump, "Stack Trace")
+	assert.Regexp(t, `common/errors_test\.go:[0-9]+ - trace 1`, dump)
+	assert.Regexp(t, `common/errors_test\.go:[0-9]+ - trace 2`, dump)
+	assert.Regexp(t, `common/errors_test\.go:[0-9]+ - trace 3`, dump)
+}
+
+func TestErrorWrapError(t *testing.T) {
+	var err1 error = NewError("my message")
+	var err2 error = ErrorWrap(err1, "another message")
+	assert.Equal(t, err1, err2)
+}

common/io.go

@@ -20,9 +20,8 @@ func (pr *PrefixedReader) Read(p []byte) (n int, err error) {
 		read := copy(p, pr.Prefix)
 		pr.Prefix = pr.Prefix[read:]
 		return read, nil
-	} else {
-		return pr.reader.Read(p)
 	}
+	return pr.reader.Read(p)
 }
 
 // NOTE: Not goroutine safe

common/nil.go

@@ -0,0 +1,29 @@
+package common
+
+import "reflect"
+
+// Go lacks a simple and safe way to see if something is a typed nil.
+// See:
+//  - https://dave.cheney.net/2017/08/09/typed-nils-in-go-2
+//  - https://groups.google.com/forum/#!topic/golang-nuts/wnH302gBa4I/discussion
+//  - https://github.com/golang/go/issues/21538
+func IsTypedNil(o interface{}) bool {
+	rv := reflect.ValueOf(o)
+	switch rv.Kind() {
+	case reflect.Chan, reflect.Func, reflect.Map, reflect.Ptr, reflect.Slice:
+		return rv.IsNil()
+	default:
+		return false
+	}
+}
+
+// Returns true if it has zero length.
+func IsEmpty(o interface{}) bool {
+	rv := reflect.ValueOf(o)
+	switch rv.Kind() {
+	case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice, reflect.String:
+		return rv.Len() == 0
+	default:
+		return false
+	}
+}

common/os.go

@@ -148,6 +148,9 @@ func WriteFileAtomic(filename string, data []byte, perm os.FileMode) error {
 	} else if n < len(data) {
 		return io.ErrShortWrite
 	}
+	// Close the file before renaming it, otherwise it will cause "The process 
+	// cannot access the file because it is being used by another process." on windows.
+	f.Close()
 
 	return os.Rename(f.Name(), filename)
 }
@@ -183,11 +186,10 @@ func Prompt(prompt string, defaultValue string) (string, error) {
 	line, err := reader.ReadString('\n')
 	if err != nil {
 		return defaultValue, err
-	} else {
-		line = strings.TrimSpace(line)
-		if line == "" {
-			return defaultValue, nil
-		}
-		return line, nil
 	}
+	line = strings.TrimSpace(line)
+	if line == "" {
+		return defaultValue, nil
+	}
+	return line, nil
 }

common/random.go

@@ -13,34 +13,150 @@ const (
 
 // pseudo random number generator.
 // seeded with OS randomness (crand)
-var prng struct {
+
+type Rand struct {
 	sync.Mutex
-	*mrand.Rand
+	rand *mrand.Rand
+}
+
+var grand *Rand
+
+func init() {
+	grand = NewRand()
+	grand.init()
+}
+
+func NewRand() *Rand {
+	rand := &Rand{}
+	rand.init()
+	return rand
 }
 
-func reset() {
-	b := cRandBytes(8)
+func (r *Rand) init() {
+	bz := cRandBytes(8)
 	var seed uint64
 	for i := 0; i < 8; i++ {
-		seed |= uint64(b[i])
+		seed |= uint64(bz[i])
 		seed <<= 8
 	}
-	prng.Lock()
-	prng.Rand = mrand.New(mrand.NewSource(int64(seed)))
-	prng.Unlock()
+	r.reset(int64(seed))
 }
 
-func init() {
-	reset()
+func (r *Rand) reset(seed int64) {
+	r.rand = mrand.New(mrand.NewSource(seed))
+}
+
+//----------------------------------------
+// Global functions
+
+func Seed(seed int64) {
+	grand.Seed(seed)
+}
+
+func RandStr(length int) string {
+	return grand.Str(length)
+}
+
+func RandUint16() uint16 {
+	return grand.Uint16()
+}
+
+func RandUint32() uint32 {
+	return grand.Uint32()
+}
+
+func RandUint64() uint64 {
+	return grand.Uint64()
+}
+
+func RandUint() uint {
+	return grand.Uint()
+}
+
+func RandInt16() int16 {
+	return grand.Int16()
+}
+
+func RandInt32() int32 {
+	return grand.Int32()
+}
+
+func RandInt64() int64 {
+	return grand.Int64()
+}
+
+func RandInt() int {
+	return grand.Int()
+}
+
+func RandInt31() int32 {
+	return grand.Int31()
+}
+
+func RandInt31n(n int32) int32 {
+	return grand.Int31n(n)
+}
+
+func RandInt63() int64 {
+	return grand.Int63()
+}
+
+func RandInt63n(n int64) int64 {
+	return grand.Int63n(n)
+}
+
+func RandUint16Exp() uint16 {
+	return grand.Uint16Exp()
+}
+
+func RandUint32Exp() uint32 {
+	return grand.Uint32Exp()
+}
+
+func RandUint64Exp() uint64 {
+	return grand.Uint64Exp()
+}
+
+func RandFloat32() float32 {
+	return grand.Float32()
+}
+
+func RandFloat64() float64 {
+	return grand.Float64()
+}
+
+func RandTime() time.Time {
+	return grand.Time()
+}
+
+func RandBytes(n int) []byte {
+	return grand.Bytes(n)
+}
+
+func RandIntn(n int) int {
+	return grand.Intn(n)
+}
+
+func RandPerm(n int) []int {
+	return grand.Perm(n)
+}
+
+//----------------------------------------
+// Rand methods
+
+func (r *Rand) Seed(seed int64) {
+	r.Lock()
+	r.reset(seed)
+	r.Unlock()
 }
 
 // Constructs an alphanumeric string of given length.
 // It is not safe for cryptographic usage.
-func RandStr(length int) string {
+func (r *Rand) Str(length int) string {
 	chars := []byte{}
 MAIN_LOOP:
 	for {
-		val := RandInt63()
+		val := r.Int63()
 		for i := 0; i < 10; i++ {
 			v := int(val & 0x3f) // rightmost 6 bits
 			if v >= 62 {         // only 62 characters in strChars
@@ -60,127 +176,151 @@ MAIN_LOOP:
 }
 
 // It is not safe for cryptographic usage.
-func RandUint16() uint16 {
-	return uint16(RandUint32() & (1<<16 - 1))
+func (r *Rand) Uint16() uint16 {
+	return uint16(r.Uint32() & (1<<16 - 1))
 }
 
 // It is not safe for cryptographic usage.
-func RandUint32() uint32 {
-	prng.Lock()
-	u32 := prng.Uint32()
-	prng.Unlock()
+func (r *Rand) Uint32() uint32 {
+	r.Lock()
+	u32 := r.rand.Uint32()
+	r.Unlock()
 	return u32
 }
 
 // It is not safe for cryptographic usage.
-func RandUint64() uint64 {
-	return uint64(RandUint32())<<32 + uint64(RandUint32())
+func (r *Rand) Uint64() uint64 {
+	return uint64(r.Uint32())<<32 + uint64(r.Uint32())
 }
 
 // It is not safe for cryptographic usage.
-func RandUint() uint {
-	prng.Lock()
-	i := prng.Int()
-	prng.Unlock()
+func (r *Rand) Uint() uint {
+	r.Lock()
+	i := r.rand.Int()
+	r.Unlock()
 	return uint(i)
 }
 
 // It is not safe for cryptographic usage.
-func RandInt16() int16 {
-	return int16(RandUint32() & (1<<16 - 1))
+func (r *Rand) Int16() int16 {
+	return int16(r.Uint32() & (1<<16 - 1))
 }
 
 // It is not safe for cryptographic usage.
-func RandInt32() int32 {
-	return int32(RandUint32())
+func (r *Rand) Int32() int32 {
+	return int32(r.Uint32())
 }
 
 // It is not safe for cryptographic usage.
-func RandInt64() int64 {
-	return int64(RandUint64())
+func (r *Rand) Int64() int64 {
+	return int64(r.Uint64())
 }
 
 // It is not safe for cryptographic usage.
-func RandInt() int {
-	prng.Lock()
-	i := prng.Int()
-	prng.Unlock()
+func (r *Rand) Int() int {
+	r.Lock()
+	i := r.rand.Int()
+	r.Unlock()
 	return i
 }
 
 // It is not safe for cryptographic usage.
-func RandInt31() int32 {
-	prng.Lock()
-	i31 := prng.Int31()
-	prng.Unlock()
+func (r *Rand) Int31() int32 {
+	r.Lock()
+	i31 := r.rand.Int31()
+	r.Unlock()
 	return i31
 }
 
 // It is not safe for cryptographic usage.
-func RandInt63() int64 {
-	prng.Lock()
-	i63 := prng.Int63()
-	prng.Unlock()
+func (r *Rand) Int31n(n int32) int32 {
+	r.Lock()
+	i31n := r.rand.Int31n(n)
+	r.Unlock()
+	return i31n
+}
+
+// It is not safe for cryptographic usage.
+func (r *Rand) Int63() int64 {
+	r.Lock()
+	i63 := r.rand.Int63()
+	r.Unlock()
 	return i63
 }
 
+// It is not safe for cryptographic usage.
+func (r *Rand) Int63n(n int64) int64 {
+	r.Lock()
+	i63n := r.rand.Int63n(n)
+	r.Unlock()
+	return i63n
+}
+
 // Distributed pseudo-exponentially to test for various cases
 // It is not safe for cryptographic usage.
-func RandUint16Exp() uint16 {
-	bits := RandUint32() % 16
+func (r *Rand) Uint16Exp() uint16 {
+	bits := r.Uint32() % 16
 	if bits == 0 {
 		return 0
 	}
 	n := uint16(1 << (bits - 1))
-	n += uint16(RandInt31()) & ((1 << (bits - 1)) - 1)
+	n += uint16(r.Int31()) & ((1 << (bits - 1)) - 1)
 	return n
 }
 
 // Distributed pseudo-exponentially to test for various cases
 // It is not safe for cryptographic usage.
-func RandUint32Exp() uint32 {
-	bits := RandUint32() % 32
+func (r *Rand) Uint32Exp() uint32 {
+	bits := r.Uint32() % 32
 	if bits == 0 {
 		return 0
 	}
 	n := uint32(1 << (bits - 1))
-	n += uint32(RandInt31()) & ((1 << (bits - 1)) - 1)
+	n += uint32(r.Int31()) & ((1 << (bits - 1)) - 1)
 	return n
 }
 
 // Distributed pseudo-exponentially to test for various cases
 // It is not safe for cryptographic usage.
-func RandUint64Exp() uint64 {
-	bits := RandUint32() % 64
+func (r *Rand) Uint64Exp() uint64 {
+	bits := r.Uint32() % 64
 	if bits == 0 {
 		return 0
 	}
 	n := uint64(1 << (bits - 1))
-	n += uint64(RandInt63()) & ((1 << (bits - 1)) - 1)
+	n += uint64(r.Int63()) & ((1 << (bits - 1)) - 1)
 	return n
 }
 
 // It is not safe for cryptographic usage.
-func RandFloat32() float32 {
-	prng.Lock()
-	f32 := prng.Float32()
-	prng.Unlock()
+func (r *Rand) Float32() float32 {
+	r.Lock()
+	f32 := r.rand.Float32()
+	r.Unlock()
 	return f32
 }
 
 // It is not safe for cryptographic usage.
-func RandTime() time.Time {
-	return time.Unix(int64(RandUint64Exp()), 0)
+func (r *Rand) Float64() float64 {
+	r.Lock()
+	f64 := r.rand.Float64()
+	r.Unlock()
+	return f64
+}
+
+// It is not safe for cryptographic usage.
+func (r *Rand) Time() time.Time {
+	return time.Unix(int64(r.Uint64Exp()), 0)
 }
 
 // RandBytes returns n random bytes from the OS's source of entropy ie. via crypto/rand.
 // It is not safe for cryptographic usage.
-func RandBytes(n int) []byte {
+func (r *Rand) Bytes(n int) []byte {
 	// cRandBytes isn't guaranteed to be fast so instead
 	// use random bytes generated from the internal PRNG
 	bs := make([]byte, n)
 	for i := 0; i < len(bs); i++ {
-		bs[i] = byte(RandInt() & 0xFF)
+		bs[i] = byte(r.Int() & 0xFF)
 	}
 	return bs
 }
@@ -188,19 +328,19 @@ func RandBytes(n int) []byte {
 // RandIntn returns, as an int, a non-negative pseudo-random number in [0, n).
 // It panics if n <= 0.
 // It is not safe for cryptographic usage.
-func RandIntn(n int) int {
-	prng.Lock()
-	i := prng.Intn(n)
-	prng.Unlock()
+func (r *Rand) Intn(n int) int {
+	r.Lock()
+	i := r.rand.Intn(n)
+	r.Unlock()
 	return i
 }
 
 // RandPerm returns a pseudo-random permutation of n integers in [0, n).
 // It is not safe for cryptographic usage.
-func RandPerm(n int) []int {
-	prng.Lock()
-	perm := prng.Perm(n)
-	prng.Unlock()
+func (r *Rand) Perm(n int) []int {
+	r.Lock()
+	perm := r.rand.Perm(n)
+	r.Unlock()
 	return perm
 }
 

common/random_test.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"io"
 	mrand "math/rand"
 	"sync"
 	"testing"
@@ -33,37 +32,38 @@ func TestRandIntn(t *testing.T) {
 	}
 }
 
-// It is essential that these tests run and never repeat their outputs
-// lest we've been pwned and the behavior of our randomness is controlled.
-// See Issues:
-//  * https://github.com/tendermint/tmlibs/issues/99
-//  * https://github.com/tendermint/tendermint/issues/973
-func TestUniqueRng(t *testing.T) {
-	buf := new(bytes.Buffer)
-	outputs := make(map[string][]int)
+// Test to make sure that we never call math.rand().
+// We do this by ensuring that outputs are deterministic.
+func TestDeterminism(t *testing.T) {
+	var firstOutput string
+
+	// Set math/rand's seed for the sake of debugging this test.
+	// (It isn't strictly necessary).
+	mrand.Seed(1)
+
 	for i := 0; i < 100; i++ {
-		testThemAll(buf)
-		output := buf.String()
-		buf.Reset()
-		runs, seen := outputs[output]
-		if seen {
-			t.Errorf("Run #%d's output was already seen in previous runs: %v", i, runs)
+		output := testThemAll()
+		if i == 0 {
+			firstOutput = output
+		} else {
+			if firstOutput != output {
+				t.Errorf("Run #%d's output was different from first run.\nfirst: %v\nlast: %v",
+					i, firstOutput, output)
+			}
 		}
-		outputs[output] = append(outputs[output], i)
 	}
 }
 
-func testThemAll(out io.Writer) {
-	// Reset the internal PRNG
-	reset()
+func testThemAll() string {
 
-	// Set math/rand's Seed so that any direct invocations
-	// of math/rand will reveal themselves.
-	mrand.Seed(1)
+	// Such determinism.
+	grand.reset(1)
+
+	// Use it.
+	out := new(bytes.Buffer)
 	perm := RandPerm(10)
 	blob, _ := json.Marshal(perm)
 	fmt.Fprintf(out, "perm: %s\n", blob)
-
 	fmt.Fprintf(out, "randInt: %d\n", RandInt())
 	fmt.Fprintf(out, "randUint: %d\n", RandUint())
 	fmt.Fprintf(out, "randIntn: %d\n", RandIntn(97))
@@ -76,6 +76,7 @@ func testThemAll(out io.Writer) {
 	fmt.Fprintf(out, "randUint16Exp: %d\n", RandUint16Exp())
 	fmt.Fprintf(out, "randUint32Exp: %d\n", RandUint32Exp())
 	fmt.Fprintf(out, "randUint64Exp: %d\n", RandUint64Exp())
+	return out.String()
 }
 
 func TestRngConcurrencySafety(t *testing.T) {

common/service.go

@@ -125,9 +125,8 @@ func (bs *BaseService) Start() error {
 		if atomic.LoadUint32(&bs.stopped) == 1 {
 			bs.Logger.Error(Fmt("Not starting %v -- already stopped", bs.name), "impl", bs.impl)
 			return ErrAlreadyStopped
-		} else {
-			bs.Logger.Info(Fmt("Starting %v", bs.name), "impl", bs.impl)
 		}
+		bs.Logger.Info(Fmt("Starting %v", bs.name), "impl", bs.impl)
 		err := bs.impl.OnStart()
 		if err != nil {
 			// revert flag
@@ -135,10 +134,9 @@ func (bs *BaseService) Start() error {
 			return err
 		}
 		return nil
-	} else {
-		bs.Logger.Debug(Fmt("Not starting %v -- already started", bs.name), "impl", bs.impl)
-		return ErrAlreadyStarted
 	}
+	bs.Logger.Debug(Fmt("Not starting %v -- already started", bs.name), "impl", bs.impl)
+	return ErrAlreadyStarted
 }
 
 // OnStart implements Service by doing nothing.
@@ -154,10 +152,9 @@ func (bs *BaseService) Stop() error {
 		bs.impl.OnStop()
 		close(bs.quit)
 		return nil
-	} else {
-		bs.Logger.Debug(Fmt("Stopping %v (ignoring: already stopped)", bs.name), "impl", bs.impl)
-		return ErrAlreadyStopped
 	}
+	bs.Logger.Debug(Fmt("Stopping %v (ignoring: already stopped)", bs.name), "impl", bs.impl)
+	return ErrAlreadyStopped
 }
 
 // OnStop implements Service by doing nothing.

common/string.go

@@ -6,25 +6,12 @@ import (
 	"strings"
 )
 
-// Fmt shorthand, XXX DEPRECATED
-var Fmt = fmt.Sprintf
-
-// RightPadString adds spaces to the right of a string to make it length totalLength
-func RightPadString(s string, totalLength int) string {
-	remaining := totalLength - len(s)
-	if remaining > 0 {
-		s = s + strings.Repeat(" ", remaining)
-	}
-	return s
-}
-
-// LeftPadString adds spaces to the left of a string to make it length totalLength
-func LeftPadString(s string, totalLength int) string {
-	remaining := totalLength - len(s)
-	if remaining > 0 {
-		s = strings.Repeat(" ", remaining) + s
+// Like fmt.Sprintf, but skips formatting if args are empty.
+var Fmt = func(format string, a ...interface{}) string {
+	if len(a) == 0 {
+		return format
 	}
-	return s
+	return fmt.Sprintf(format, a...)
 }
 
 // IsHex returns true for non-empty hex-string prefixed with "0x"
@@ -53,3 +40,20 @@ func StringInSlice(a string, list []string) bool {
 	}
 	return false
 }
+
+// SplitAndTrim slices s into all subslices separated by sep and returns a
+// slice of the string s with all leading and trailing Unicode code points
+// contained in cutset removed. If sep is empty, SplitAndTrim splits after each
+// UTF-8 sequence. First part is equivalent to strings.SplitN with a count of
+// -1.
+func SplitAndTrim(s, sep, cutset string) []string {
+	if s == "" {
+		return []string{}
+	}
+
+	spl := strings.Split(s, sep)
+	for i := 0; i < len(spl); i++ {
+		spl[i] = strings.Trim(spl[i], cutset)
+	}
+	return spl
+}

common/string_test.go

@@ -30,3 +30,22 @@ func TestIsHex(t *testing.T) {
 		assert.True(t, IsHex(v), "%q is hex", v)
 	}
 }
+
+func TestSplitAndTrim(t *testing.T) {
+	testCases := []struct {
+		s        string
+		sep      string
+		cutset   string
+		expected []string
+	}{
+		{"a,b,c", ",", " ", []string{"a", "b", "c"}},
+		{" a , b , c ", ",", " ", []string{"a", "b", "c"}},
+		{" a, b, c ", ",", " ", []string{"a", "b", "c"}},
+		{" , ", ",", " ", []string{"", ""}},
+		{"   ", ",", " ", []string{""}},
+	}
+
+	for _, tc := range testCases {
+		assert.Equal(t, tc.expected, SplitAndTrim(tc.s, tc.sep, tc.cutset), "%s", tc.s)
+	}
+}

common/types.pb.go

@@ -1,6 +1,5 @@
-// Code generated by protoc-gen-gogo.
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
 // source: common/types.proto
-// DO NOT EDIT!
 
 /*
 Package common is a generated protocol buffer package.

common/word.go

@@ -72,9 +72,8 @@ func (tuple Tuple256) Compare(other Tuple256) int {
 	firstCompare := tuple.First.Compare(other.First)
 	if firstCompare == 0 {
 		return tuple.Second.Compare(other.Second)
-	} else {
-		return firstCompare
 	}
+	return firstCompare
 }
 
 func Tuple256Split(t Tuple256) (Word256, Word256) {

db/backend_test.go

@@ -47,7 +47,7 @@ func testBackendGetSetDelete(t *testing.T, backend DBBackendType) {
 }
 
 func TestBackendsGetSetDelete(t *testing.T) {
-	for dbType, _ := range backends {
+	for dbType := range backends {
 		testBackendGetSetDelete(t, dbType)
 	}
 }

db/c_level_db.go

@@ -171,6 +171,14 @@ func (mBatch *cLevelDBBatch) Write() {
 	}
 }
 
+// Implements Batch.
+func (mBatch *cLevelDBBatch) WriteSync() {
+	err := mBatch.db.db.Write(mBatch.db.woSync, mBatch.batch)
+	if err != nil {
+		panic(err)
+	}
+}
+
 //----------------------------------------
 // Iterator
 // NOTE This is almost identical to db/go_level_db.Iterator

db/common_test.go

@@ -2,6 +2,7 @@ package db
 
 import (
 	"fmt"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -9,6 +10,14 @@ import (
 	cmn "github.com/tendermint/tmlibs/common"
 )
 
+//----------------------------------------
+// Helper functions.
+
+func checkValue(t *testing.T, db DB, key []byte, valueWanted []byte) {
+	valueGot := db.Get(key)
+	assert.Equal(t, valueWanted, valueGot)
+}
+
 func checkValid(t *testing.T, itr Iterator, expected bool) {
 	valid := itr.Valid()
 	require.Equal(t, expected, valid)
@@ -46,110 +55,131 @@ func checkValuePanics(t *testing.T, itr Iterator) {
 }
 
 func newTempDB(t *testing.T, backend DBBackendType) (db DB) {
-	dir, dirname := cmn.Tempdir("test_go_iterator")
+	dir, dirname := cmn.Tempdir("db_common_test")
 	db = NewDB("testdb", backend, dirname)
 	dir.Close()
 	return db
 }
 
-func TestDBIteratorSingleKey(t *testing.T) {
-	for backend, _ := range backends {
-		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
-			db := newTempDB(t, backend)
-			db.SetSync(bz("1"), bz("value_1"))
-			itr := db.Iterator(nil, nil)
+//----------------------------------------
+// mockDB
 
-			checkValid(t, itr, true)
-			checkNext(t, itr, false)
-			checkValid(t, itr, false)
-			checkNextPanics(t, itr)
+// NOTE: not actually goroutine safe.
+// If you want something goroutine safe, maybe you just want a MemDB.
+type mockDB struct {
+	mtx   sync.Mutex
+	calls map[string]int
+}
 
-			// Once invalid...
-			checkInvalid(t, itr)
-		})
+func newMockDB() *mockDB {
+	return &mockDB{
+		calls: make(map[string]int),
 	}
 }
 
-func TestDBIteratorTwoKeys(t *testing.T) {
-	for backend, _ := range backends {
-		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
-			db := newTempDB(t, backend)
-			db.SetSync(bz("1"), bz("value_1"))
-			db.SetSync(bz("2"), bz("value_1"))
+func (mdb *mockDB) Mutex() *sync.Mutex {
+	return &(mdb.mtx)
+}
 
-			{ // Fail by calling Next too much
-				itr := db.Iterator(nil, nil)
-				checkValid(t, itr, true)
+func (mdb *mockDB) Get([]byte) []byte {
+	mdb.calls["Get"]++
+	return nil
+}
 
-				checkNext(t, itr, true)
-				checkValid(t, itr, true)
+func (mdb *mockDB) Has([]byte) bool {
+	mdb.calls["Has"]++
+	return false
+}
 
-				checkNext(t, itr, false)
-				checkValid(t, itr, false)
+func (mdb *mockDB) Set([]byte, []byte) {
+	mdb.calls["Set"]++
+}
 
-				checkNextPanics(t, itr)
+func (mdb *mockDB) SetSync([]byte, []byte) {
+	mdb.calls["SetSync"]++
+}
 
-				// Once invalid...
-				checkInvalid(t, itr)
-			}
-		})
-	}
+func (mdb *mockDB) SetNoLock([]byte, []byte) {
+	mdb.calls["SetNoLock"]++
 }
 
-func TestDBIteratorMany(t *testing.T) {
-	for backend, _ := range backends {
-		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
-			db := newTempDB(t, backend)
+func (mdb *mockDB) SetNoLockSync([]byte, []byte) {
+	mdb.calls["SetNoLockSync"]++
+}
 
-			keys := make([][]byte, 100)
-			for i := 0; i < 100; i++ {
-				keys[i] = []byte{byte(i)}
-			}
+func (mdb *mockDB) Delete([]byte) {
+	mdb.calls["Delete"]++
+}
 
-			value := []byte{5}
-			for _, k := range keys {
-				db.Set(k, value)
-			}
+func (mdb *mockDB) DeleteSync([]byte) {
+	mdb.calls["DeleteSync"]++
+}
 
-			itr := db.Iterator(nil, nil)
-			defer itr.Close()
-			for ; itr.Valid(); itr.Next() {
-				assert.Equal(t, db.Get(itr.Key()), itr.Value())
-			}
-		})
-	}
+func (mdb *mockDB) DeleteNoLock([]byte) {
+	mdb.calls["DeleteNoLock"]++
 }
 
-func TestDBIteratorEmpty(t *testing.T) {
-	for backend, _ := range backends {
-		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
-			db := newTempDB(t, backend)
-			itr := db.Iterator(nil, nil)
+func (mdb *mockDB) DeleteNoLockSync([]byte) {
+	mdb.calls["DeleteNoLockSync"]++
+}
 
-			checkInvalid(t, itr)
-		})
-	}
+func (mdb *mockDB) Iterator(start, end []byte) Iterator {
+	mdb.calls["Iterator"]++
+	return &mockIterator{}
 }
 
-func TestDBIteratorEmptyBeginAfter(t *testing.T) {
-	for backend, _ := range backends {
-		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
-			db := newTempDB(t, backend)
-			itr := db.Iterator(bz("1"), nil)
+func (mdb *mockDB) ReverseIterator(start, end []byte) Iterator {
+	mdb.calls["ReverseIterator"]++
+	return &mockIterator{}
+}
 
-			checkInvalid(t, itr)
-		})
-	}
+func (mdb *mockDB) Close() {
+	mdb.calls["Close"]++
 }
 
-func TestDBIteratorNonemptyBeginAfter(t *testing.T) {
-	for backend, _ := range backends {
-		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
-			db := newTempDB(t, backend)
-			db.SetSync(bz("1"), bz("value_1"))
-			itr := db.Iterator(bz("2"), nil)
+func (mdb *mockDB) NewBatch() Batch {
+	mdb.calls["NewBatch"]++
+	return &memBatch{db: mdb}
+}
+
+func (mdb *mockDB) Print() {
+	mdb.calls["Print"]++
+	fmt.Printf("mockDB{%v}", mdb.Stats())
+}
 
-			checkInvalid(t, itr)
-		})
+func (mdb *mockDB) Stats() map[string]string {
+	mdb.calls["Stats"]++
+
+	res := make(map[string]string)
+	for key, count := range mdb.calls {
+		res[key] = fmt.Sprintf("%d", count)
 	}
+	return res
+}
+
+//----------------------------------------
+// mockIterator
+
+type mockIterator struct{}
+
+func (mockIterator) Domain() (start []byte, end []byte) {
+	return nil, nil
+}
+
+func (mockIterator) Valid() bool {
+	return false
+}
+
+func (mockIterator) Next() {
+}
+
+func (mockIterator) Key() []byte {
+	return nil
+}
+
+func (mockIterator) Value() []byte {
+	return nil
+}
+
+func (mockIterator) Close() {
 }

db/db_test.go

@@ -0,0 +1,194 @@
+package db
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDBIteratorSingleKey(t *testing.T) {
+	for backend := range backends {
+		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
+			db := newTempDB(t, backend)
+			db.SetSync(bz("1"), bz("value_1"))
+			itr := db.Iterator(nil, nil)
+
+			checkValid(t, itr, true)
+			checkNext(t, itr, false)
+			checkValid(t, itr, false)
+			checkNextPanics(t, itr)
+
+			// Once invalid...
+			checkInvalid(t, itr)
+		})
+	}
+}
+
+func TestDBIteratorTwoKeys(t *testing.T) {
+	for backend := range backends {
+		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
+			db := newTempDB(t, backend)
+			db.SetSync(bz("1"), bz("value_1"))
+			db.SetSync(bz("2"), bz("value_1"))
+
+			{ // Fail by calling Next too much
+				itr := db.Iterator(nil, nil)
+				checkValid(t, itr, true)
+
+				checkNext(t, itr, true)
+				checkValid(t, itr, true)
+
+				checkNext(t, itr, false)
+				checkValid(t, itr, false)
+
+				checkNextPanics(t, itr)
+
+				// Once invalid...
+				checkInvalid(t, itr)
+			}
+		})
+	}
+}
+
+func TestDBIteratorMany(t *testing.T) {
+	for backend := range backends {
+		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
+			db := newTempDB(t, backend)
+
+			keys := make([][]byte, 100)
+			for i := 0; i < 100; i++ {
+				keys[i] = []byte{byte(i)}
+			}
+
+			value := []byte{5}
+			for _, k := range keys {
+				db.Set(k, value)
+			}
+
+			itr := db.Iterator(nil, nil)
+			defer itr.Close()
+			for ; itr.Valid(); itr.Next() {
+				assert.Equal(t, db.Get(itr.Key()), itr.Value())
+			}
+		})
+	}
+}
+
+func TestDBIteratorEmpty(t *testing.T) {
+	for backend := range backends {
+		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
+			db := newTempDB(t, backend)
+			itr := db.Iterator(nil, nil)
+
+			checkInvalid(t, itr)
+		})
+	}
+}
+
+func TestDBIteratorEmptyBeginAfter(t *testing.T) {
+	for backend := range backends {
+		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
+			db := newTempDB(t, backend)
+			itr := db.Iterator(bz("1"), nil)
+
+			checkInvalid(t, itr)
+		})
+	}
+}
+
+func TestDBIteratorNonemptyBeginAfter(t *testing.T) {
+	for backend := range backends {
+		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {
+			db := newTempDB(t, backend)
+			db.SetSync(bz("1"), bz("value_1"))
+			itr := db.Iterator(bz("2"), nil)
+
+			checkInvalid(t, itr)
+		})
+	}
+}
+
+func TestDBBatchWrite1(t *testing.T) {
+	mdb := newMockDB()
+	ddb := NewDebugDB(t.Name(), mdb)
+	batch := ddb.NewBatch()
+
+	batch.Set(bz("1"), bz("1"))
+	batch.Set(bz("2"), bz("2"))
+	batch.Delete(bz("3"))
+	batch.Set(bz("4"), bz("4"))
+	batch.Write()
+
+	assert.Equal(t, 0, mdb.calls["Set"])
+	assert.Equal(t, 0, mdb.calls["SetSync"])
+	assert.Equal(t, 3, mdb.calls["SetNoLock"])
+	assert.Equal(t, 0, mdb.calls["SetNoLockSync"])
+	assert.Equal(t, 0, mdb.calls["Delete"])
+	assert.Equal(t, 0, mdb.calls["DeleteSync"])
+	assert.Equal(t, 1, mdb.calls["DeleteNoLock"])
+	assert.Equal(t, 0, mdb.calls["DeleteNoLockSync"])
+}
+
+func TestDBBatchWrite2(t *testing.T) {
+	mdb := newMockDB()
+	ddb := NewDebugDB(t.Name(), mdb)
+	batch := ddb.NewBatch()
+
+	batch.Set(bz("1"), bz("1"))
+	batch.Set(bz("2"), bz("2"))
+	batch.Set(bz("4"), bz("4"))
+	batch.Delete(bz("3"))
+	batch.Write()
+
+	assert.Equal(t, 0, mdb.calls["Set"])
+	assert.Equal(t, 0, mdb.calls["SetSync"])
+	assert.Equal(t, 3, mdb.calls["SetNoLock"])
+	assert.Equal(t, 0, mdb.calls["SetNoLockSync"])
+	assert.Equal(t, 0, mdb.calls["Delete"])
+	assert.Equal(t, 0, mdb.calls["DeleteSync"])
+	assert.Equal(t, 1, mdb.calls["DeleteNoLock"])
+	assert.Equal(t, 0, mdb.calls["DeleteNoLockSync"])
+}
+
+func TestDBBatchWriteSync1(t *testing.T) {
+	mdb := newMockDB()
+	ddb := NewDebugDB(t.Name(), mdb)
+	batch := ddb.NewBatch()
+
+	batch.Set(bz("1"), bz("1"))
+	batch.Set(bz("2"), bz("2"))
+	batch.Delete(bz("3"))
+	batch.Set(bz("4"), bz("4"))
+	batch.WriteSync()
+
+	assert.Equal(t, 0, mdb.calls["Set"])
+	assert.Equal(t, 0, mdb.calls["SetSync"])
+	assert.Equal(t, 2, mdb.calls["SetNoLock"])
+	assert.Equal(t, 1, mdb.calls["SetNoLockSync"])
+	assert.Equal(t, 0, mdb.calls["Delete"])
+	assert.Equal(t, 0, mdb.calls["DeleteSync"])
+	assert.Equal(t, 1, mdb.calls["DeleteNoLock"])
+	assert.Equal(t, 0, mdb.calls["DeleteNoLockSync"])
+}
+
+func TestDBBatchWriteSync2(t *testing.T) {
+	mdb := newMockDB()
+	ddb := NewDebugDB(t.Name(), mdb)
+	batch := ddb.NewBatch()
+
+	batch.Set(bz("1"), bz("1"))
+	batch.Set(bz("2"), bz("2"))
+	batch.Set(bz("4"), bz("4"))
+	batch.Delete(bz("3"))
+	batch.WriteSync()
+
+	assert.Equal(t, 0, mdb.calls["Set"])
+	assert.Equal(t, 0, mdb.calls["SetSync"])
+	assert.Equal(t, 3, mdb.calls["SetNoLock"])
+	assert.Equal(t, 0, mdb.calls["SetNoLockSync"])
+	assert.Equal(t, 0, mdb.calls["Delete"])
+	assert.Equal(t, 0, mdb.calls["DeleteSync"])
+	assert.Equal(t, 0, mdb.calls["DeleteNoLock"])
+	assert.Equal(t, 1, mdb.calls["DeleteNoLockSync"])
+}

db/debug_db.go

@@ -0,0 +1,216 @@
+package db
+
+import (
+	"fmt"
+	"sync"
+)
+
+//----------------------------------------
+// debugDB
+
+type debugDB struct {
+	label string
+	db    DB
+}
+
+// For printing all operationgs to the console for debugging.
+func NewDebugDB(label string, db DB) debugDB {
+	return debugDB{
+		label: label,
+		db:    db,
+	}
+}
+
+// Implements atomicSetDeleter.
+func (ddb debugDB) Mutex() *sync.Mutex { return nil }
+
+// Implements DB.
+func (ddb debugDB) Get(key []byte) (value []byte) {
+	defer fmt.Printf("%v.Get(%X) %X\n", ddb.label, key, value)
+	value = ddb.db.Get(key)
+	return
+}
+
+// Implements DB.
+func (ddb debugDB) Has(key []byte) (has bool) {
+	defer fmt.Printf("%v.Has(%X) %v\n", ddb.label, key, has)
+	return ddb.db.Has(key)
+}
+
+// Implements DB.
+func (ddb debugDB) Set(key []byte, value []byte) {
+	fmt.Printf("%v.Set(%X, %X)\n", ddb.label, key, value)
+	ddb.db.Set(key, value)
+}
+
+// Implements DB.
+func (ddb debugDB) SetSync(key []byte, value []byte) {
+	fmt.Printf("%v.SetSync(%X, %X)\n", ddb.label, key, value)
+	ddb.db.SetSync(key, value)
+}
+
+// Implements atomicSetDeleter.
+func (ddb debugDB) SetNoLock(key []byte, value []byte) {
+	fmt.Printf("%v.SetNoLock(%X, %X)\n", ddb.label, key, value)
+	ddb.db.Set(key, value)
+}
+
+// Implements atomicSetDeleter.
+func (ddb debugDB) SetNoLockSync(key []byte, value []byte) {
+	fmt.Printf("%v.SetNoLockSync(%X, %X)\n", ddb.label, key, value)
+	ddb.db.SetSync(key, value)
+}
+
+// Implements DB.
+func (ddb debugDB) Delete(key []byte) {
+	fmt.Printf("%v.Delete(%X)\n", ddb.label, key)
+	ddb.db.Delete(key)
+}
+
+// Implements DB.
+func (ddb debugDB) DeleteSync(key []byte) {
+	fmt.Printf("%v.DeleteSync(%X)\n", ddb.label, key)
+	ddb.db.DeleteSync(key)
+}
+
+// Implements atomicSetDeleter.
+func (ddb debugDB) DeleteNoLock(key []byte) {
+	fmt.Printf("%v.DeleteNoLock(%X)\n", ddb.label, key)
+	ddb.db.Delete(key)
+}
+
+// Implements atomicSetDeleter.
+func (ddb debugDB) DeleteNoLockSync(key []byte) {
+	fmt.Printf("%v.DeleteNoLockSync(%X)\n", ddb.label, key)
+	ddb.db.DeleteSync(key)
+}
+
+// Implements DB.
+func (ddb debugDB) Iterator(start, end []byte) Iterator {
+	fmt.Printf("%v.Iterator(%X, %X)\n", ddb.label, start, end)
+	return NewDebugIterator(ddb.label, ddb.db.Iterator(start, end))
+}
+
+// Implements DB.
+func (ddb debugDB) ReverseIterator(start, end []byte) Iterator {
+	fmt.Printf("%v.ReverseIterator(%X, %X)\n", ddb.label, start, end)
+	return NewDebugIterator(ddb.label, ddb.db.ReverseIterator(start, end))
+}
+
+// Implements DB.
+func (ddb debugDB) NewBatch() Batch {
+	fmt.Printf("%v.NewBatch()\n", ddb.label)
+	return NewDebugBatch(ddb.label, ddb.db.NewBatch())
+}
+
+// Implements DB.
+func (ddb debugDB) Close() {
+	fmt.Printf("%v.Close()\n", ddb.label)
+	ddb.db.Close()
+}
+
+// Implements DB.
+func (ddb debugDB) Print() {
+	ddb.db.Print()
+}
+
+// Implements DB.
+func (ddb debugDB) Stats() map[string]string {
+	return ddb.db.Stats()
+}
+
+//----------------------------------------
+// debugIterator
+
+type debugIterator struct {
+	label string
+	itr   Iterator
+}
+
+// For printing all operationgs to the console for debugging.
+func NewDebugIterator(label string, itr Iterator) debugIterator {
+	return debugIterator{
+		label: label,
+		itr:   itr,
+	}
+}
+
+// Implements Iterator.
+func (ditr debugIterator) Domain() (start []byte, end []byte) {
+	defer fmt.Printf("%v.itr.Domain() (%X,%X)\n", ditr.label, start, end)
+	start, end = ditr.itr.Domain()
+	return
+}
+
+// Implements Iterator.
+func (ditr debugIterator) Valid() (ok bool) {
+	defer fmt.Printf("%v.itr.Valid() %v\n", ditr.label, ok)
+	ok = ditr.itr.Valid()
+	return
+}
+
+// Implements Iterator.
+func (ditr debugIterator) Next() {
+	fmt.Printf("%v.itr.Next()\n", ditr.label)
+	ditr.itr.Next()
+}
+
+// Implements Iterator.
+func (ditr debugIterator) Key() (key []byte) {
+	fmt.Printf("%v.itr.Key() %X\n", ditr.label, key)
+	key = ditr.itr.Key()
+	return
+}
+
+// Implements Iterator.
+func (ditr debugIterator) Value() (value []byte) {
+	fmt.Printf("%v.itr.Value() %X\n", ditr.label, value)
+	value = ditr.itr.Value()
+	return
+}
+
+// Implements Iterator.
+func (ditr debugIterator) Close() {
+	fmt.Printf("%v.itr.Close()\n", ditr.label)
+	ditr.itr.Close()
+}
+
+//----------------------------------------
+// debugBatch
+
+type debugBatch struct {
+	label string
+	bch   Batch
+}
+
+// For printing all operationgs to the console for debugging.
+func NewDebugBatch(label string, bch Batch) debugBatch {
+	return debugBatch{
+		label: label,
+		bch:   bch,
+	}
+}
+
+// Implements Batch.
+func (dbch debugBatch) Set(key, value []byte) {
+	fmt.Printf("%v.batch.Set(%X, %X)\n", dbch.label, key, value)
+	dbch.bch.Set(key, value)
+}
+
+// Implements Batch.
+func (dbch debugBatch) Delete(key []byte) {
+	fmt.Printf("%v.batch.Delete(%X)\n", dbch.label, key)
+	dbch.bch.Delete(key)
+}
+
+// Implements Batch.
+func (dbch debugBatch) Write() {
+	fmt.Printf("%v.batch.Write()\n", dbch.label)
+	dbch.bch.Write()
+}
+
+// Implements Batch.
+func (dbch debugBatch) WriteSync() {
+	fmt.Printf("%v.batch.WriteSync()\n", dbch.label)
+	dbch.bch.WriteSync()
+}

db/go_level_db.go

@@ -10,7 +10,7 @@ import (
 	"github.com/syndtr/goleveldb/leveldb/iterator"
 	"github.com/syndtr/goleveldb/leveldb/opt"
 
-	. "github.com/tendermint/tmlibs/common"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 func init() {
@@ -46,9 +46,8 @@ func (db *GoLevelDB) Get(key []byte) []byte {
 	if err != nil {
 		if err == errors.ErrNotFound {
 			return nil
-		} else {
-			panic(err)
 		}
+		panic(err)
 	}
 	return res
 }
@@ -64,7 +63,7 @@ func (db *GoLevelDB) Set(key []byte, value []byte) {
 	value = nonNilBytes(value)
 	err := db.db.Put(key, value, nil)
 	if err != nil {
-		PanicCrisis(err)
+		cmn.PanicCrisis(err)
 	}
 }
 
@@ -74,7 +73,7 @@ func (db *GoLevelDB) SetSync(key []byte, value []byte) {
 	value = nonNilBytes(value)
 	err := db.db.Put(key, value, &opt.WriteOptions{Sync: true})
 	if err != nil {
-		PanicCrisis(err)
+		cmn.PanicCrisis(err)
 	}
 }
 
@@ -83,7 +82,7 @@ func (db *GoLevelDB) Delete(key []byte) {
 	key = nonNilBytes(key)
 	err := db.db.Delete(key, nil)
 	if err != nil {
-		PanicCrisis(err)
+		cmn.PanicCrisis(err)
 	}
 }
 
@@ -92,7 +91,7 @@ func (db *GoLevelDB) DeleteSync(key []byte) {
 	key = nonNilBytes(key)
 	err := db.db.Delete(key, &opt.WriteOptions{Sync: true})
 	if err != nil {
-		PanicCrisis(err)
+		cmn.PanicCrisis(err)
 	}
 }
 
@@ -110,10 +109,10 @@ func (db *GoLevelDB) Print() {
 	str, _ := db.db.GetProperty("leveldb.stats")
 	fmt.Printf("%v\n", str)
 
-	iter := db.db.NewIterator(nil, nil)
-	for iter.Next() {
-		key := iter.Key()
-		value := iter.Value()
+	itr := db.db.NewIterator(nil, nil)
+	for itr.Next() {
+		key := itr.Key()
+		value := itr.Value()
 		fmt.Printf("[%X]:\t[%X]\n", key, value)
 	}
 }
@@ -167,7 +166,15 @@ func (mBatch *goLevelDBBatch) Delete(key []byte) {
 
 // Implements Batch.
 func (mBatch *goLevelDBBatch) Write() {
-	err := mBatch.db.db.Write(mBatch.batch, nil)
+	err := mBatch.db.db.Write(mBatch.batch, &opt.WriteOptions{Sync: false})
+	if err != nil {
+		panic(err)
+	}
+}
+
+// Implements Batch.
+func (mBatch *goLevelDBBatch) WriteSync() {
+	err := mBatch.db.db.Write(mBatch.batch, &opt.WriteOptions{Sync: true})
 	if err != nil {
 		panic(err)
 	}

db/go_level_db_test.go

@@ -30,7 +30,7 @@ func BenchmarkRandomReadsWrites(b *testing.B) {
 		// Write something
 		{
 			idx := (int64(cmn.RandInt()) % numItems)
-			internal[idx] += 1
+			internal[idx]++
 			val := internal[idx]
 			idxBytes := int642Bytes(int64(idx))
 			valBytes := int642Bytes(int64(val))

db/mem_batch.go

@@ -5,7 +5,9 @@ import "sync"
 type atomicSetDeleter interface {
 	Mutex() *sync.Mutex
 	SetNoLock(key, value []byte)
+	SetNoLockSync(key, value []byte)
 	DeleteNoLock(key []byte)
+	DeleteNoLockSync(key []byte)
 }
 
 type memBatch struct {
@@ -35,16 +37,35 @@ func (mBatch *memBatch) Delete(key []byte) {
 }
 
 func (mBatch *memBatch) Write() {
-	mtx := mBatch.db.Mutex()
-	mtx.Lock()
-	defer mtx.Unlock()
+	mBatch.write(false)
+}
+
+func (mBatch *memBatch) WriteSync() {
+	mBatch.write(true)
+}
 
-	for _, op := range mBatch.ops {
+func (mBatch *memBatch) write(doSync bool) {
+	if mtx := mBatch.db.Mutex(); mtx != nil {
+		mtx.Lock()
+		defer mtx.Unlock()
+	}
+
+	for i, op := range mBatch.ops {
+		if doSync && i == (len(mBatch.ops)-1) {
+			switch op.opType {
+			case opTypeSet:
+				mBatch.db.SetNoLockSync(op.key, op.value)
+			case opTypeDelete:
+				mBatch.db.DeleteNoLockSync(op.key)
+			}
+			break // we're done.
+		}
 		switch op.opType {
 		case opTypeSet:
 			mBatch.db.SetNoLock(op.key, op.value)
 		case opTypeDelete:
 			mBatch.db.DeleteNoLock(op.key)
 		}
+
 	}
 }

db/mem_db.go

@@ -26,6 +26,11 @@ func NewMemDB() *MemDB {
 	return database
 }
 
+// Implements atomicSetDeleter.
+func (db *MemDB) Mutex() *sync.Mutex {
+	return &(db.mtx)
+}
+
 // Implements DB.
 func (db *MemDB) Get(key []byte) []byte {
 	db.mtx.Lock()
@@ -63,6 +68,11 @@ func (db *MemDB) SetSync(key []byte, value []byte) {
 
 // Implements atomicSetDeleter.
 func (db *MemDB) SetNoLock(key []byte, value []byte) {
+	db.SetNoLockSync(key, value)
+}
+
+// Implements atomicSetDeleter.
+func (db *MemDB) SetNoLockSync(key []byte, value []byte) {
 	key = nonNilBytes(key)
 	value = nonNilBytes(value)
 
@@ -87,6 +97,11 @@ func (db *MemDB) DeleteSync(key []byte) {
 
 // Implements atomicSetDeleter.
 func (db *MemDB) DeleteNoLock(key []byte) {
+	db.DeleteNoLockSync(key)
+}
+
+// Implements atomicSetDeleter.
+func (db *MemDB) DeleteNoLockSync(key []byte) {
 	key = nonNilBytes(key)
 
 	delete(db.db, string(key))
@@ -122,9 +137,6 @@ func (db *MemDB) Stats() map[string]string {
 	return stats
 }
 
-//----------------------------------------
-// Batch
-
 // Implements DB.
 func (db *MemDB) NewBatch() Batch {
 	db.mtx.Lock()
@@ -133,10 +145,6 @@ func (db *MemDB) NewBatch() Batch {
 	return &memBatch{db, nil}
 }
 
-func (db *MemDB) Mutex() *sync.Mutex {
-	return &(db.mtx)
-}
-
 //----------------------------------------
 // Iterator
 
@@ -227,7 +235,7 @@ func (itr *memDBIterator) assertIsValid() {
 
 func (db *MemDB) getSortedKeys(start, end []byte, reverse bool) []string {
 	keys := []string{}
-	for key, _ := range db.db {
+	for key := range db.db {
 		if IsKeyInDomain([]byte(key), start, end, false) {
 			keys = append(keys, key)
 		}

db/prefix_db.go

@@ -0,0 +1,263 @@
+package db
+
+import (
+	"bytes"
+	"fmt"
+	"sync"
+)
+
+// IteratePrefix is a convenience function for iterating over a key domain
+// restricted by prefix.
+func IteratePrefix(db DB, prefix []byte) Iterator {
+	var start, end []byte
+	if len(prefix) == 0 {
+		start = nil
+		end = nil
+	} else {
+		start = cp(prefix)
+		end = cpIncr(prefix)
+	}
+	return db.Iterator(start, end)
+}
+
+/*
+TODO: Make test, maybe rename.
+// Like IteratePrefix but the iterator strips the prefix from the keys.
+func IteratePrefixStripped(db DB, prefix []byte) Iterator {
+	return newUnprefixIterator(prefix, IteratePrefix(db, prefix))
+}
+*/
+
+//----------------------------------------
+// prefixDB
+
+type prefixDB struct {
+	mtx    sync.Mutex
+	prefix []byte
+	db     DB
+}
+
+// NewPrefixDB lets you namespace multiple DBs within a single DB.
+func NewPrefixDB(db DB, prefix []byte) *prefixDB {
+	return &prefixDB{
+		prefix: prefix,
+		db:     db,
+	}
+}
+
+// Implements atomicSetDeleter.
+func (pdb *prefixDB) Mutex() *sync.Mutex {
+	return &(pdb.mtx)
+}
+
+// Implements DB.
+func (pdb *prefixDB) Get(key []byte) []byte {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	return pdb.db.Get(pdb.prefixed(key))
+}
+
+// Implements DB.
+func (pdb *prefixDB) Has(key []byte) bool {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	return pdb.db.Has(pdb.prefixed(key))
+}
+
+// Implements DB.
+func (pdb *prefixDB) Set(key []byte, value []byte) {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	pdb.db.Set(pdb.prefixed(key), value)
+}
+
+// Implements DB.
+func (pdb *prefixDB) SetSync(key []byte, value []byte) {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	pdb.db.SetSync(pdb.prefixed(key), value)
+}
+
+// Implements atomicSetDeleter.
+func (pdb *prefixDB) SetNoLock(key []byte, value []byte) {
+	pdb.db.Set(pdb.prefixed(key), value)
+}
+
+// Implements atomicSetDeleter.
+func (pdb *prefixDB) SetNoLockSync(key []byte, value []byte) {
+	pdb.db.SetSync(pdb.prefixed(key), value)
+}
+
+// Implements DB.
+func (pdb *prefixDB) Delete(key []byte) {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	pdb.db.Delete(pdb.prefixed(key))
+}
+
+// Implements DB.
+func (pdb *prefixDB) DeleteSync(key []byte) {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	pdb.db.DeleteSync(pdb.prefixed(key))
+}
+
+// Implements atomicSetDeleter.
+func (pdb *prefixDB) DeleteNoLock(key []byte) {
+	pdb.db.Delete(pdb.prefixed(key))
+}
+
+// Implements atomicSetDeleter.
+func (pdb *prefixDB) DeleteNoLockSync(key []byte) {
+	pdb.db.DeleteSync(pdb.prefixed(key))
+}
+
+// Implements DB.
+func (pdb *prefixDB) Iterator(start, end []byte) Iterator {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	pstart := append(pdb.prefix, start...)
+	pend := []byte(nil)
+	if end != nil {
+		pend = append(pdb.prefix, end...)
+	}
+	return newUnprefixIterator(
+		pdb.prefix,
+		pdb.db.Iterator(
+			pstart,
+			pend,
+		),
+	)
+}
+
+// Implements DB.
+func (pdb *prefixDB) ReverseIterator(start, end []byte) Iterator {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	pstart := []byte(nil)
+	if start != nil {
+		pstart = append(pdb.prefix, start...)
+	}
+	pend := []byte(nil)
+	if end != nil {
+		pend = append(pdb.prefix, end...)
+	}
+	return newUnprefixIterator(
+		pdb.prefix,
+		pdb.db.ReverseIterator(
+			pstart,
+			pend,
+		),
+	)
+}
+
+// Implements DB.
+func (pdb *prefixDB) NewBatch() Batch {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	return &memBatch{pdb, nil}
+}
+
+// Implements DB.
+func (pdb *prefixDB) Close() {
+	pdb.mtx.Lock()
+	defer pdb.mtx.Unlock()
+
+	pdb.db.Close()
+}
+
+// Implements DB.
+func (pdb *prefixDB) Print() {
+	fmt.Printf("prefix: %X\n", pdb.prefix)
+
+	itr := pdb.Iterator(nil, nil)
+	defer itr.Close()
+	for ; itr.Valid(); itr.Next() {
+		key := itr.Key()
+		value := itr.Value()
+		fmt.Printf("[%X]:\t[%X]\n", key, value)
+	}
+}
+
+// Implements DB.
+func (pdb *prefixDB) Stats() map[string]string {
+	stats := make(map[string]string)
+	stats["prefixdb.prefix.string"] = string(pdb.prefix)
+	stats["prefixdb.prefix.hex"] = fmt.Sprintf("%X", pdb.prefix)
+	source := pdb.db.Stats()
+	for key, value := range source {
+		stats["prefixdb.source."+key] = value
+	}
+	return stats
+}
+
+func (pdb *prefixDB) prefixed(key []byte) []byte {
+	return append(pdb.prefix, key...)
+}
+
+//----------------------------------------
+
+// Strips prefix while iterating from Iterator.
+type unprefixIterator struct {
+	prefix []byte
+	source Iterator
+}
+
+func newUnprefixIterator(prefix []byte, source Iterator) unprefixIterator {
+	return unprefixIterator{
+		prefix: prefix,
+		source: source,
+	}
+}
+
+func (itr unprefixIterator) Domain() (start []byte, end []byte) {
+	start, end = itr.source.Domain()
+	if len(start) > 0 {
+		start = stripPrefix(start, itr.prefix)
+	}
+	if len(end) > 0 {
+		end = stripPrefix(end, itr.prefix)
+	}
+	return
+}
+
+func (itr unprefixIterator) Valid() bool {
+	return itr.source.Valid()
+}
+
+func (itr unprefixIterator) Next() {
+	itr.source.Next()
+}
+
+func (itr unprefixIterator) Key() (key []byte) {
+	return stripPrefix(itr.source.Key(), itr.prefix)
+}
+
+func (itr unprefixIterator) Value() (value []byte) {
+	return itr.source.Value()
+}
+
+func (itr unprefixIterator) Close() {
+	itr.source.Close()
+}
+
+//----------------------------------------
+
+func stripPrefix(key []byte, prefix []byte) (stripped []byte) {
+	if len(key) < len(prefix) {
+		panic("should not happen")
+	}
+	if !bytes.Equal(key[:len(prefix)], prefix) {
+		panic("should not happne")
+	}
+	return key[len(prefix):]
+}

db/prefix_db_test.go

@@ -0,0 +1,44 @@
+package db
+
+import "testing"
+
+func TestIteratePrefix(t *testing.T) {
+	db := NewMemDB()
+	// Under "key" prefix
+	db.Set(bz("key"), bz("value"))
+	db.Set(bz("key1"), bz("value1"))
+	db.Set(bz("key2"), bz("value2"))
+	db.Set(bz("key3"), bz("value3"))
+	db.Set(bz("something"), bz("else"))
+	db.Set(bz(""), bz(""))
+	db.Set(bz("k"), bz("val"))
+	db.Set(bz("ke"), bz("valu"))
+	db.Set(bz("kee"), bz("valuu"))
+	xitr := db.Iterator(nil, nil)
+	xitr.Key()
+
+	pdb := NewPrefixDB(db, bz("key"))
+	checkValue(t, pdb, bz("key"), nil)
+	checkValue(t, pdb, bz(""), bz("value"))
+	checkValue(t, pdb, bz("key1"), nil)
+	checkValue(t, pdb, bz("1"), bz("value1"))
+	checkValue(t, pdb, bz("key2"), nil)
+	checkValue(t, pdb, bz("2"), bz("value2"))
+	checkValue(t, pdb, bz("key3"), nil)
+	checkValue(t, pdb, bz("3"), bz("value3"))
+	checkValue(t, pdb, bz("something"), nil)
+	checkValue(t, pdb, bz("k"), nil)
+	checkValue(t, pdb, bz("ke"), nil)
+	checkValue(t, pdb, bz("kee"), nil)
+
+	itr := pdb.Iterator(nil, nil)
+	itr.Key()
+	checkItem(t, itr, bz(""), bz("value"))
+	checkNext(t, itr, true)
+	checkItem(t, itr, bz("1"), bz("value1"))
+	checkNext(t, itr, true)
+	checkItem(t, itr, bz("2"), bz("value2"))
+	checkNext(t, itr, true)
+	checkItem(t, itr, bz("3"), bz("value3"))
+	itr.Close()
+}

db/types.go

@@ -1,5 +1,6 @@
 package db
 
+// DBs are goroutine safe.
 type DB interface {
 
 	// Get returns nil iff key doesn't exist.
@@ -35,7 +36,7 @@ type DB interface {
 	// Iterate over a domain of keys in descending order. End is exclusive.
 	// Start must be greater than end, or the Iterator is invalid.
 	// If start is nil, iterates from the last/greatest item (inclusive).
-	// If end is nil, iterates up to the first/least item (iclusive).
+	// If end is nil, iterates up to the first/least item (inclusive).
 	// CONTRACT: No writes may happen within a domain while an iterator exists over it.
 	// CONTRACT: start, end readonly []byte
 	ReverseIterator(start, end []byte) Iterator
@@ -59,6 +60,7 @@ type DB interface {
 type Batch interface {
 	SetDeleter
 	Write()
+	WriteSync()
 }
 
 type SetDeleter interface {
@@ -127,7 +129,6 @@ func bz(s string) []byte {
 func nonNilBytes(bz []byte) []byte {
 	if bz == nil {
 		return []byte{}
-	} else {
-		return bz
 	}
+	return bz
 }

db/util.go

@@ -4,35 +4,30 @@ import (
 	"bytes"
 )
 
-func IteratePrefix(db DB, prefix []byte) Iterator {
-	var start, end []byte
-	if len(prefix) == 0 {
-		start = nil
-		end = nil
-	} else {
-		start = cp(prefix)
-		end = cpIncr(prefix)
-	}
-	return db.Iterator(start, end)
-}
-
-//----------------------------------------
-
 func cp(bz []byte) (ret []byte) {
 	ret = make([]byte, len(bz))
 	copy(ret, bz)
 	return ret
 }
 
+// Returns a slice of the same length (big endian)
+// except incremented by one.
+// Returns nil on overflow (e.g. if bz bytes are all 0xFF)
 // CONTRACT: len(bz) > 0
 func cpIncr(bz []byte) (ret []byte) {
+	if len(bz) == 0 {
+		panic("cpIncr expects non-zero bz length")
+	}
 	ret = cp(bz)
 	for i := len(bz) - 1; i >= 0; i-- {
 		if ret[i] < byte(0xFF) {
-			ret[i] += 1
+			ret[i]++
 			return
-		} else {
-			ret[i] = byte(0x00)
+		}
+		ret[i] = byte(0x00)
+		if i == 0 {
+			// Overflow
+			return nil
 		}
 	}
 	return nil
@@ -48,13 +43,12 @@ func IsKeyInDomain(key, start, end []byte, isReverse bool) bool {
 			return false
 		}
 		return true
-	} else {
-		if start != nil && bytes.Compare(start, key) < 0 {
-			return false
-		}
-		if end != nil && bytes.Compare(key, end) <= 0 {
-			return false
-		}
-		return true
 	}
+	if start != nil && bytes.Compare(start, key) < 0 {
+		return false
+	}
+	if end != nil && bytes.Compare(key, end) <= 0 {
+		return false
+	}
+	return true
 }

db/util_test.go

@@ -7,7 +7,7 @@ import (
 
 // Empty iterator for empty db.
 func TestPrefixIteratorNoMatchNil(t *testing.T) {
-	for backend, _ := range backends {
+	for backend := range backends {
 		t.Run(fmt.Sprintf("Prefix w/ backend %s", backend), func(t *testing.T) {
 			db := newTempDB(t, backend)
 			itr := IteratePrefix(db, []byte("2"))
@@ -19,7 +19,7 @@ func TestPrefixIteratorNoMatchNil(t *testing.T) {
 
 // Empty iterator for db populated after iterator created.
 func TestPrefixIteratorNoMatch1(t *testing.T) {
-	for backend, _ := range backends {
+	for backend := range backends {
 		t.Run(fmt.Sprintf("Prefix w/ backend %s", backend), func(t *testing.T) {
 			db := newTempDB(t, backend)
 			itr := IteratePrefix(db, []byte("2"))
@@ -32,7 +32,7 @@ func TestPrefixIteratorNoMatch1(t *testing.T) {
 
 // Empty iterator for prefix starting after db entry.
 func TestPrefixIteratorNoMatch2(t *testing.T) {
-	for backend, _ := range backends {
+	for backend := range backends {
 		t.Run(fmt.Sprintf("Prefix w/ backend %s", backend), func(t *testing.T) {
 			db := newTempDB(t, backend)
 			db.SetSync(bz("3"), bz("value_3"))
@@ -45,7 +45,7 @@ func TestPrefixIteratorNoMatch2(t *testing.T) {
 
 // Iterator with single val for db with single val, starting from that val.
 func TestPrefixIteratorMatch1(t *testing.T) {
-	for backend, _ := range backends {
+	for backend := range backends {
 		t.Run(fmt.Sprintf("Prefix w/ backend %s", backend), func(t *testing.T) {
 			db := newTempDB(t, backend)
 			db.SetSync(bz("2"), bz("value_2"))
@@ -63,7 +63,7 @@ func TestPrefixIteratorMatch1(t *testing.T) {
 
 // Iterator with prefix iterates over everything with same prefix.
 func TestPrefixIteratorMatches1N(t *testing.T) {
-	for backend, _ := range backends {
+	for backend := range backends {
 		t.Run(fmt.Sprintf("Prefix w/ backend %s", backend), func(t *testing.T) {
 			db := newTempDB(t, backend)
 

events/README.md

@@ -95,7 +95,7 @@ type EventCallback func(data EventData)
 type EventData interface {
 }
 ```
-Generic event data can be typed and registered with tendermint/go-wire
+Generic event data can be typed and registered with tendermint/go-amino
 via concrete implementation of this interface
 
 

events/events.go

@@ -6,10 +6,10 @@ package events
 import (
 	"sync"
 
-	. "github.com/tendermint/tmlibs/common"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
-// Generic event data can be typed and registered with tendermint/go-wire
+// Generic event data can be typed and registered with tendermint/go-amino
 // via concrete implementation of this interface
 type EventData interface {
 	//AssertIsEventData()
@@ -27,7 +27,7 @@ type Fireable interface {
 }
 
 type EventSwitch interface {
-	Service
+	cmn.Service
 	Fireable
 
 	AddListenerForEvent(listenerID, event string, cb EventCallback)
@@ -36,7 +36,7 @@ type EventSwitch interface {
 }
 
 type eventSwitch struct {
-	BaseService
+	cmn.BaseService
 
 	mtx        sync.RWMutex
 	eventCells map[string]*eventCell
@@ -45,7 +45,7 @@ type eventSwitch struct {
 
 func NewEventSwitch() EventSwitch {
 	evsw := &eventSwitch{}
-	evsw.BaseService = *NewBaseService(nil, "EventSwitch", evsw)
+	evsw.BaseService = *cmn.NewBaseService(nil, "EventSwitch", evsw)
 	return evsw
 }
 

events/events_test.go

@@ -221,11 +221,11 @@ func TestRemoveListener(t *testing.T) {
 	// add some listeners and make sure they work
 	evsw.AddListenerForEvent("listener", "event1",
 		func(data EventData) {
-			sum1 += 1
+			sum1++
 		})
 	evsw.AddListenerForEvent("listener", "event2",
 		func(data EventData) {
-			sum2 += 1
+			sum2++
 		})
 	for i := 0; i < count; i++ {
 		evsw.FireEvent("event1", true)

flowrate/io_test.go

@@ -121,7 +121,15 @@ func TestWriter(t *testing.T) {
 	w.SetBlocking(true)
 	if n, err := w.Write(b[20:]); n != 80 || err != nil {
 		t.Fatalf("w.Write(b[20:]) expected 80 (<nil>); got %v (%v)", n, err)
-	} else if rt := time.Since(start); rt < _400ms {
+	} else if rt := time.Since(start); rt < _300ms {
+		// Explanation for `rt < _300ms` (as opposed to `< _400ms`)
+		//
+		//                 |<-- start        |        |
+		// epochs: -----0ms|---100ms|---200ms|---300ms|---400ms
+		// sends:        20|20      |20      |20      |20#
+		//
+		// NOTE: The '#' symbol can thus happen before 400ms is up.
+		// Thus, we can only panic if rt < _300ms.
 		t.Fatalf("w.Write(b[20:]) returned ahead of time (%v)", rt)
 	}
 

merkle/simple_map_test.go

@@ -17,37 +17,37 @@ func TestSimpleMap(t *testing.T) {
 	{
 		db := NewSimpleMap()
 		db.Set("key1", strHasher("value1"))
-		assert.Equal(t, "19618304d1ad2635c4238bce87f72331b22a11a1", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		assert.Equal(t, "acdb4f121bc6f25041eb263ab463f1cd79236a32", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
 		db.Set("key1", strHasher("value2"))
-		assert.Equal(t, "51cb96d3d41e1714def72eb4bacc211de9ddf284", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		assert.Equal(t, "b8cbf5adee8c524e14f531da9b49adbbbd66fffa", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
 		db.Set("key1", strHasher("value1"))
 		db.Set("key2", strHasher("value2"))
-		assert.Equal(t, "58a0a99d5019fdcad4bcf55942e833b2dfab9421", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		assert.Equal(t, "1708aabc85bbe00242d3db8c299516aa54e48c38", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
 		db.Set("key2", strHasher("value2")) // NOTE: out of order
 		db.Set("key1", strHasher("value1"))
-		assert.Equal(t, "58a0a99d5019fdcad4bcf55942e833b2dfab9421", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		assert.Equal(t, "1708aabc85bbe00242d3db8c299516aa54e48c38", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
 		db.Set("key1", strHasher("value1"))
 		db.Set("key2", strHasher("value2"))
 		db.Set("key3", strHasher("value3"))
-		assert.Equal(t, "cb56db3c7993e977f4c2789559ae3e5e468a6e9b", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		assert.Equal(t, "e728afe72ce351eed6aca65c5f78da19b9a6e214", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 	{
 		db := NewSimpleMap()
 		db.Set("key2", strHasher("value2")) // NOTE: out of order
 		db.Set("key1", strHasher("value1"))
 		db.Set("key3", strHasher("value3"))
-		assert.Equal(t, "cb56db3c7993e977f4c2789559ae3e5e468a6e9b", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
+		assert.Equal(t, "e728afe72ce351eed6aca65c5f78da19b9a6e214", fmt.Sprintf("%x", db.Hash()), "Hash didn't match")
 	}
 }

merkle/simple_proof.go

@@ -43,9 +43,9 @@ func (sp *SimpleProof) StringIndented(indent string) string {
 
 // Use the leafHash and innerHashes to get the root merkle hash.
 // If the length of the innerHashes slice isn't exactly correct, the result is nil.
+// Recursive impl.
 func computeHashFromAunts(index int, total int, leafHash []byte, innerHashes [][]byte) []byte {
-	// Recursive impl.
-	if index >= total {
+	if index >= total || index < 0 || total <= 0 {
 		return nil
 	}
 	switch total {
@@ -67,13 +67,12 @@ func computeHashFromAunts(index int, total int, leafHash []byte, innerHashes [][
 				return nil
 			}
 			return SimpleHashFromTwoHashes(leftHash, innerHashes[len(innerHashes)-1])
-		} else {
-			rightHash := computeHashFromAunts(index-numLeft, total-numLeft, leafHash, innerHashes[:len(innerHashes)-1])
-			if rightHash == nil {
-				return nil
-			}
-			return SimpleHashFromTwoHashes(innerHashes[len(innerHashes)-1], rightHash)
 		}
+		rightHash := computeHashFromAunts(index-numLeft, total-numLeft, leafHash, innerHashes[:len(innerHashes)-1])
+		if rightHash == nil {
+			return nil
+		}
+		return SimpleHashFromTwoHashes(innerHashes[len(innerHashes)-1], rightHash)
 	}
 }
 
@@ -81,7 +80,7 @@ func computeHashFromAunts(index int, total int, leafHash []byte, innerHashes [][
 // The node and the tree is thrown away afterwards.
 // Exactly one of node.Left and node.Right is nil, unless node is the root, in which case both are nil.
 // node.Parent.Hash = hash(node.Hash, node.Right.Hash) or
-// 									  hash(node.Left.Hash, node.Hash), depending on whether node is a left/right child.
+// hash(node.Left.Hash, node.Hash), depending on whether node is a left/right child.
 type SimpleProofNode struct {
 	Hash   []byte
 	Parent *SimpleProofNode

merkle/simple_tree.go

@@ -31,6 +31,9 @@ import (
 func SimpleHashFromTwoHashes(left []byte, right []byte) []byte {
 	var hasher = ripemd160.New()
 	err := encodeByteSlice(hasher, left)
+	if err != nil {
+		panic(err)
+	}
 	err = encodeByteSlice(hasher, right)
 	if err != nil {
 		panic(err)

merkle/types.go

@@ -28,10 +28,10 @@ type Hasher interface {
 }
 
 //-----------------------------------------------------------------------
-// NOTE: these are duplicated from go-wire so we dont need go-wire as a dep
+// NOTE: these are duplicated from go-amino so we dont need go-amino as a dep
 
 func encodeByteSlice(w io.Writer, bz []byte) (err error) {
-	err = encodeVarint(w, int64(len(bz)))
+	err = encodeUvarint(w, uint64(len(bz)))
 	if err != nil {
 		return
 	}
@@ -39,9 +39,9 @@ func encodeByteSlice(w io.Writer, bz []byte) (err error) {
 	return
 }
 
-func encodeVarint(w io.Writer, i int64) (err error) {
+func encodeUvarint(w io.Writer, i uint64) (err error) {
 	var buf [10]byte
-	n := binary.PutVarint(buf[:], i)
+	n := binary.PutUvarint(buf[:], i)
 	_, err = w.Write(buf[0:n])
 	return
 }

pubsub/pubsub.go

@@ -28,6 +28,16 @@ const (
 	shutdown
 )
 
+var (
+	// ErrSubscriptionNotFound is returned when a client tries to unsubscribe
+	// from not existing subscription.
+	ErrSubscriptionNotFound = errors.New("subscription not found")
+
+	// ErrAlreadySubscribed is returned when a client tries to subscribe twice or
+	// more using the same query.
+	ErrAlreadySubscribed = errors.New("already subscribed")
+)
+
 type cmd struct {
 	op       operation
 	query    Query
@@ -52,7 +62,7 @@ type Server struct {
 	cmdsCap int
 
 	mtx           sync.RWMutex
-	subscriptions map[string]map[string]struct{} // subscriber -> query -> struct{}
+	subscriptions map[string]map[string]Query // subscriber -> query (string) -> Query
 }
 
 // Option sets a parameter for the server.
@@ -63,7 +73,7 @@ type Option func(*Server)
 // provided, the resulting server's queue is unbuffered.
 func NewServer(options ...Option) *Server {
 	s := &Server{
-		subscriptions: make(map[string]map[string]struct{}),
+		subscriptions: make(map[string]map[string]Query),
 	}
 	s.BaseService = *cmn.NewBaseService(nil, "PubSub", s)
 
@@ -106,16 +116,16 @@ func (s *Server) Subscribe(ctx context.Context, clientID string, query Query, ou
 	}
 	s.mtx.RUnlock()
 	if ok {
-		return errors.New("already subscribed")
+		return ErrAlreadySubscribed
 	}
 
 	select {
 	case s.cmds <- cmd{op: sub, clientID: clientID, query: query, ch: out}:
 		s.mtx.Lock()
 		if _, ok = s.subscriptions[clientID]; !ok {
-			s.subscriptions[clientID] = make(map[string]struct{})
+			s.subscriptions[clientID] = make(map[string]Query)
 		}
-		s.subscriptions[clientID][query.String()] = struct{}{}
+		s.subscriptions[clientID][query.String()] = query
 		s.mtx.Unlock()
 		return nil
 	case <-ctx.Done():
@@ -127,18 +137,20 @@ func (s *Server) Subscribe(ctx context.Context, clientID string, query Query, ou
 // returned to the caller if the context is canceled or if subscription does
 // not exist.
 func (s *Server) Unsubscribe(ctx context.Context, clientID string, query Query) error {
+	var origQuery Query
 	s.mtx.RLock()
 	clientSubscriptions, ok := s.subscriptions[clientID]
 	if ok {
-		_, ok = clientSubscriptions[query.String()]
+		origQuery, ok = clientSubscriptions[query.String()]
 	}
 	s.mtx.RUnlock()
 	if !ok {
-		return errors.New("subscription not found")
+		return ErrSubscriptionNotFound
 	}
 
+	// original query is used here because we're using pointers as map keys
 	select {
-	case s.cmds <- cmd{op: unsub, clientID: clientID, query: query}:
+	case s.cmds <- cmd{op: unsub, clientID: clientID, query: origQuery}:
 		s.mtx.Lock()
 		delete(clientSubscriptions, query.String())
 		s.mtx.Unlock()
@@ -155,7 +167,7 @@ func (s *Server) UnsubscribeAll(ctx context.Context, clientID string) error {
 	_, ok := s.subscriptions[clientID]
 	s.mtx.RUnlock()
 	if !ok {
-		return errors.New("subscription not found")
+		return ErrSubscriptionNotFound
 	}
 
 	select {
@@ -209,6 +221,11 @@ func (s *Server) OnStart() error {
 	return nil
 }
 
+// OnReset implements Service.OnReset
+func (s *Server) OnReset() error {
+	return nil
+}
+
 func (s *Server) loop(state state) {
 loop:
 	for cmd := range s.cmds {

pubsub/pubsub_test.go

@@ -101,9 +101,9 @@ func TestUnsubscribe(t *testing.T) {
 
 	ctx := context.Background()
 	ch := make(chan interface{})
-	err := s.Subscribe(ctx, clientID, query.Empty{}, ch)
+	err := s.Subscribe(ctx, clientID, query.MustParse("tm.events.type='NewBlock'"), ch)
 	require.NoError(t, err)
-	err = s.Unsubscribe(ctx, clientID, query.Empty{})
+	err = s.Unsubscribe(ctx, clientID, query.MustParse("tm.events.type='NewBlock'"))
 	require.NoError(t, err)
 
 	err = s.Publish(ctx, "Nick Fury")

test/mutate.go

@@ -1,7 +1,7 @@
 package test
 
 import (
-	. "github.com/tendermint/tmlibs/common"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 // Contract: !bytes.Equal(input, output) && len(input) >= len(output)
@@ -17,11 +17,11 @@ func MutateByteSlice(bytez []byte) []byte {
 	bytez = mBytez
 
 	// Try a random mutation
-	switch RandInt() % 2 {
+	switch cmn.RandInt() % 2 {
 	case 0: // Mutate a single byte
-		bytez[RandInt()%len(bytez)] += byte(RandInt()%255 + 1)
+		bytez[cmn.RandInt()%len(bytez)] += byte(cmn.RandInt()%255 + 1)
 	case 1: // Remove an arbitrary byte
-		pos := RandInt() % len(bytez)
+		pos := cmn.RandInt() % len(bytez)
 		bytez = append(bytez[:pos], bytez[pos+1:]...)
 	}
 	return bytez

version/version.go

@@ -1,3 +1,3 @@
 package version
 
-const Version = "0.7.1"
+const Version = "0.8.1"