lib: Update v.io/x/lib/timing to a single implementation

The initial implementation of the timing package had two
implementations: a FullTimer with full timing info, and a
CompactTimer that is smaller and faster, but doesn't have full
timing info.  This is annoying for the user since they have to
make a choice, and adds complexity, and it bugged me.

This change consolidates things down to a single implementation,
and gets rid of the interfaces.  This is simpler to use for the
user.  The main point of CompactTimer was to avoid multiple small
allocations in the interval tree; the new Timer does the same
thing, while retaining full timing info.

As a bonus, the printing logic is faster, since we simply loop
through the intervals in the slice.  The printing logic for
CompactTimer was quite inefficient since it caused new
allocations for each list of children in compactInterval.

MultiPart: 2/2

Change-Id: I2fea725ccb9cd3ec0107d2d33bf1d8c32b07b452

Author: Todd Wang

cmdline/.api

@@ -25,7 +25,7 @@ pkg cmdline, type Env struct
 pkg cmdline, type Env struct, Stderr io.Writer
 pkg cmdline, type Env struct, Stdin io.Reader
 pkg cmdline, type Env struct, Stdout io.Writer
-pkg cmdline, type Env struct, Timer timing.Timer
+pkg cmdline, type Env struct, Timer *timing.Timer
 pkg cmdline, type Env struct, Usage func(*Env, io.Writer)
 pkg cmdline, type Env struct, Vars map[string]string
 pkg cmdline, type ErrExitCode int

cmdline/cmdline.go

@@ -125,7 +125,13 @@ func Main(root *Command) {
 	code := ExitCode(err, env.Stderr)
 	if *flagTime && env.Timer != nil {
 		env.Timer.Finish()
-		timing.IntervalPrinter{}.Print(env.Stderr, env.Timer.Root())
+		p := timing.IntervalPrinter{Zero: env.Timer.Zero}
+		if err := p.Print(env.Stderr, env.Timer.Intervals, env.Timer.Now()); err != nil {
+			code2 := ExitCode(err, env.Stderr)
+			if code == 0 {
+				code = code2
+			}
+		}
 	}
 	os.Exit(code)
 }

cmdline/env.go

@@ -23,7 +23,7 @@ func EnvFromOS() *Env {
 		Stdout: os.Stdout,
 		Stderr: os.Stderr,
 		Vars:   envvar.SliceToMap(os.Environ()),
-		Timer:  timing.NewFullTimer("root"),
+		Timer:  timing.NewTimer("root"),
 	}
 }
 
@@ -35,7 +35,7 @@ type Env struct {
 	Stdout io.Writer
 	Stderr io.Writer
 	Vars   map[string]string // Environment variables
-	Timer  timing.Timer
+	Timer  *timing.Timer
 
 	// Usage is a function that prints usage information to w.  Typically set by
 	// calls to Main or Parse to print usage of the leaf command.

timing/.api

@@ -1,45 +1,21 @@
-pkg timing, func IntervalDuration(Interval, time.Time) time.Duration
-pkg timing, func NewCompactTimer(string) *CompactTimer
-pkg timing, func NewFullTimer(string) *FullTimer
-pkg timing, method (*CompactTimer) Finish()
-pkg timing, method (*CompactTimer) Pop()
-pkg timing, method (*CompactTimer) Push(string)
-pkg timing, method (*CompactTimer) Root() Interval
-pkg timing, method (*CompactTimer) String() string
-pkg timing, method (*FullTimer) Finish()
-pkg timing, method (*FullTimer) Pop()
-pkg timing, method (*FullTimer) Push(string)
-pkg timing, method (*FullTimer) Root() Interval
-pkg timing, method (*FullTimer) String() string
-pkg timing, method (FullInterval) Child(int) Interval
-pkg timing, method (FullInterval) End() time.Time
-pkg timing, method (FullInterval) Name() string
-pkg timing, method (FullInterval) NumChild() int
-pkg timing, method (FullInterval) Start() time.Time
-pkg timing, method (FullInterval) String() string
-pkg timing, method (IntervalPrinter) Print(io.Writer, Interval) error
-pkg timing, type CompactTimer struct
-pkg timing, type FullInterval struct
-pkg timing, type FullInterval struct, Children []FullInterval
-pkg timing, type FullInterval struct, EndTime time.Time
-pkg timing, type FullInterval struct, Label string
-pkg timing, type FullInterval struct, StartTime time.Time
-pkg timing, type FullTimer struct
-pkg timing, type FullTimer struct, FullRoot FullInterval
-pkg timing, type Interval interface { Child, End, Name, NumChild, Start, String }
-pkg timing, type Interval interface, Child(int) Interval
-pkg timing, type Interval interface, End() time.Time
-pkg timing, type Interval interface, Name() string
-pkg timing, type Interval interface, NumChild() int
-pkg timing, type Interval interface, Start() time.Time
-pkg timing, type Interval interface, String() string
+pkg timing, const InvalidDuration time.Duration
+pkg timing, func NewTimer(string) *Timer
+pkg timing, method (*Timer) Finish()
+pkg timing, method (*Timer) Now() time.Duration
+pkg timing, method (*Timer) Pop()
+pkg timing, method (*Timer) Push(string)
+pkg timing, method (*Timer) String() string
+pkg timing, method (IntervalPrinter) Print(io.Writer, []Interval, time.Duration) error
+pkg timing, type Interval struct
+pkg timing, type Interval struct, Depth int
+pkg timing, type Interval struct, End time.Duration
+pkg timing, type Interval struct, Name string
+pkg timing, type Interval struct, Start time.Duration
 pkg timing, type IntervalPrinter struct
 pkg timing, type IntervalPrinter struct, Indent int
 pkg timing, type IntervalPrinter struct, MinGap time.Duration
 pkg timing, type IntervalPrinter struct, TimeFormat string
-pkg timing, type Timer interface { Finish, Pop, Push, Root, String }
-pkg timing, type Timer interface, Finish()
-pkg timing, type Timer interface, Pop()
-pkg timing, type Timer interface, Push(string)
-pkg timing, type Timer interface, Root() Interval
-pkg timing, type Timer interface, String() string
+pkg timing, type IntervalPrinter struct, Zero time.Time
+pkg timing, type Timer struct
+pkg timing, type Timer struct, Intervals []Interval
+pkg timing, type Timer struct, Zero time.Time