vendor: Update golang.org/x/net/...

2016-09-13 21:47:00 +02:00
parent 6af09c61be
commit 897cca0a82
69 changed files with 1994 additions and 434 deletions
@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
@@ -0,0 +1,37 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package netreflect implements run-time reflection for the
+// facilities of net package.
+package netreflect
+
+import (
+	"errors"
+	"net"
+)
+
+var (
+	errInvalidType = errors.New("invalid type")
+	errOpNoSupport = errors.New("operation not supported")
+)
+
+// SocketOf returns the socket descriptor of c.
+func SocketOf(c net.Conn) (uintptr, error) {
+	switch c.(type) {
+	case *net.TCPConn, *net.UDPConn, *net.IPConn, *net.UnixConn:
+		return socketOf(c)
+	default:
+		return 0, errInvalidType
+	}
+}
+
+// PacketSocketOf returns the socket descriptor of c.
+func PacketSocketOf(c net.PacketConn) (uintptr, error) {
+	switch c.(type) {
+	case *net.UDPConn, *net.IPConn, *net.UnixConn:
+		return socketOf(c.(net.Conn))
+	default:
+		return 0, errInvalidType
+	}
+}
@@ -0,0 +1,30 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris windows
+
+package netreflect
+
+import (
+	"net"
+	"reflect"
+	"runtime"
+)
+
+func socketOf(c net.Conn) (uintptr, error) {
+	v := reflect.ValueOf(c)
+	switch e := v.Elem(); e.Kind() {
+	case reflect.Struct:
+		fd := e.FieldByName("conn").FieldByName("fd")
+		switch e := fd.Elem(); e.Kind() {
+		case reflect.Struct:
+			sysfd := e.FieldByName("sysfd")
+			if runtime.GOOS == "windows" {
+				return uintptr(sysfd.Uint()), nil
+			}
+			return uintptr(sysfd.Int()), nil
+		}
+	}
+	return 0, errInvalidType
+}
@@ -0,0 +1,11 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris,!windows
+
+package netreflect
+
+import "net"
+
+func socketOf(c net.Conn) (uintptr, error) { return 0, errOpNoSupport }
@@ -0,0 +1,31 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris windows
+
+package nettest
+
+import (
+	"os"
+	"syscall"
+)
+
+func protocolNotSupported(err error) bool {
+	switch err := err.(type) {
+	case syscall.Errno:
+		switch err {
+		case syscall.EPROTONOSUPPORT, syscall.ENOPROTOOPT:
+			return true
+		}
+	case *os.SyscallError:
+		switch err := err.Err.(type) {
+		case syscall.Errno:
+			switch err {
+			case syscall.EPROTONOSUPPORT, syscall.ENOPROTOOPT:
+				return true
+			}
+		}
+	}
+	return false
+}
@@ -0,0 +1,11 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build nacl plan9
+
+package nettest
+
+func protocolNotSupported(err error) bool {
+	return false
+}
@@ -0,0 +1,94 @@
+// Copyright 2012 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package nettest
+
+import "net"
+
+// IsMulticastCapable reports whether ifi is an IP multicast-capable
+// network interface. Network must be "ip", "ip4" or "ip6".
+func IsMulticastCapable(network string, ifi *net.Interface) (net.IP, bool) {
+	switch network {
+	case "ip", "ip4", "ip6":
+	default:
+		return nil, false
+	}
+	if ifi == nil || ifi.Flags&net.FlagUp == 0 || ifi.Flags&net.FlagMulticast == 0 {
+		return nil, false
+	}
+	return hasRoutableIP(network, ifi)
+}
+
+// RoutedInterface returns a network interface that can route IP
+// traffic and satisfies flags. It returns nil when an appropriate
+// network interface is not found. Network must be "ip", "ip4" or
+// "ip6".
+func RoutedInterface(network string, flags net.Flags) *net.Interface {
+	switch network {
+	case "ip", "ip4", "ip6":
+	default:
+		return nil
+	}
+	ift, err := net.Interfaces()
+	if err != nil {
+		return nil
+	}
+	for _, ifi := range ift {
+		if ifi.Flags&flags != flags {
+			continue
+		}
+		if _, ok := hasRoutableIP(network, &ifi); !ok {
+			continue
+		}
+		return &ifi
+	}
+	return nil
+}
+
+func hasRoutableIP(network string, ifi *net.Interface) (net.IP, bool) {
+	ifat, err := ifi.Addrs()
+	if err != nil {
+		return nil, false
+	}
+	for _, ifa := range ifat {
+		switch ifa := ifa.(type) {
+		case *net.IPAddr:
+			if ip := routableIP(network, ifa.IP); ip != nil {
+				return ip, true
+			}
+		case *net.IPNet:
+			if ip := routableIP(network, ifa.IP); ip != nil {
+				return ip, true
+			}
+		}
+	}
+	return nil, false
+}
+
+func routableIP(network string, ip net.IP) net.IP {
+	if !ip.IsLoopback() && !ip.IsLinkLocalUnicast() && !ip.IsGlobalUnicast() {
+		return nil
+	}
+	switch network {
+	case "ip4":
+		if ip := ip.To4(); ip != nil {
+			return ip
+		}
+	case "ip6":
+		if ip.IsLoopback() { // addressing scope of the loopback address depends on each implementation
+			return nil
+		}
+		if ip := ip.To16(); ip != nil && ip.To4() == nil {
+			return ip
+		}
+	default:
+		if ip := ip.To4(); ip != nil {
+			return ip
+		}
+		if ip := ip.To16(); ip != nil {
+			return ip
+		}
+	}
+	return nil
+}
@@ -0,0 +1,11 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package nettest
+
+const defaultMaxOpenFiles = 256
+
+// MaxOpenFiles returns the maximum number of open files for the
+// caller's process.
+func MaxOpenFiles() int { return maxOpenFiles() }
@@ -0,0 +1,9 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build nacl plan9
+
+package nettest
+
+func maxOpenFiles() int { return defaultMaxOpenFiles }
@@ -0,0 +1,17 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package nettest
+
+import "syscall"
+
+func maxOpenFiles() int {
+	var rlim syscall.Rlimit
+	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlim); err != nil {
+		return defaultMaxOpenFiles
+	}
+	return int(rlim.Cur)
+}
@@ -0,0 +1,7 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package nettest
+
+func maxOpenFiles() int { return 4 * defaultMaxOpenFiles /* actually it's 16581375 */ }
@@ -0,0 +1,36 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package nettest provides utilities for IP testing.
+package nettest // import "golang.org/x/net/internal/nettest"
+
+import "net"
+
+// SupportsIPv4 reports whether the platform supports IPv4 networking
+// functionality.
+func SupportsIPv4() bool {
+	ln, err := net.Listen("tcp4", "127.0.0.1:0")
+	if err != nil {
+		return false
+	}
+	ln.Close()
+	return true
+}
+
+// SupportsIPv6 reports whether the platform supports IPv6 networking
+// functionality.
+func SupportsIPv6() bool {
+	ln, err := net.Listen("tcp6", "[::1]:0")
+	if err != nil {
+		return false
+	}
+	ln.Close()
+	return true
+}
+
+// ProtocolNotSupported reports whether err is a protocol not
+// supported error.
+func ProtocolNotSupported(err error) bool {
+	return protocolNotSupported(err)
+}
@@ -0,0 +1,18 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build nacl plan9
+
+package nettest
+
+import (
+	"fmt"
+	"runtime"
+)
+
+// SupportsRawIPSocket reports whether the platform supports raw IP
+// sockets.
+func SupportsRawIPSocket() (string, bool) {
+	return fmt.Sprintf("not supported on %s", runtime.GOOS), false
+}
@@ -0,0 +1,22 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package nettest
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+)
+
+// SupportsRawIPSocket reports whether the platform supports raw IP
+// sockets.
+func SupportsRawIPSocket() (string, bool) {
+	if os.Getuid() != 0 {
+		return fmt.Sprintf("must be root on %s", runtime.GOOS), false
+	}
+	return "", true
+}
@@ -0,0 +1,32 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package nettest
+
+import (
+	"fmt"
+	"runtime"
+	"syscall"
+)
+
+// SupportsRawIPSocket reports whether the platform supports raw IP
+// sockets.
+func SupportsRawIPSocket() (string, bool) {
+	// From http://msdn.microsoft.com/en-us/library/windows/desktop/ms740548.aspx:
+	// Note: To use a socket of type SOCK_RAW requires administrative privileges.
+	// Users running Winsock applications that use raw sockets must be a member of
+	// the Administrators group on the local computer, otherwise raw socket calls
+	// will fail with an error code of WSAEACCES. On Windows Vista and later, access
+	// for raw sockets is enforced at socket creation. In earlier versions of Windows,
+	// access for raw sockets is enforced during other socket operations.
+	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_RAW, 0)
+	if err == syscall.WSAEACCES {
+		return fmt.Sprintf("no access to raw socket allowed on %s", runtime.GOOS), false
+	}
+	if err != nil {
+		return err.Error(), false
+	}
+	syscall.Closesocket(s)
+	return "", true
+}
@@ -0,0 +1,525 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package timeseries implements a time series structure for stats collection.
+package timeseries // import "golang.org/x/net/internal/timeseries"
+
+import (
+	"fmt"
+	"log"
+	"time"
+)
+
+const (
+	timeSeriesNumBuckets       = 64
+	minuteHourSeriesNumBuckets = 60
+)
+
+var timeSeriesResolutions = []time.Duration{
+	1 * time.Second,
+	10 * time.Second,
+	1 * time.Minute,
+	10 * time.Minute,
+	1 * time.Hour,
+	6 * time.Hour,
+	24 * time.Hour,          // 1 day
+	7 * 24 * time.Hour,      // 1 week
+	4 * 7 * 24 * time.Hour,  // 4 weeks
+	16 * 7 * 24 * time.Hour, // 16 weeks
+}
+
+var minuteHourSeriesResolutions = []time.Duration{
+	1 * time.Second,
+	1 * time.Minute,
+}
+
+// An Observable is a kind of data that can be aggregated in a time series.
+type Observable interface {
+	Multiply(ratio float64)    // Multiplies the data in self by a given ratio
+	Add(other Observable)      // Adds the data from a different observation to self
+	Clear()                    // Clears the observation so it can be reused.
+	CopyFrom(other Observable) // Copies the contents of a given observation to self
+}
+
+// Float attaches the methods of Observable to a float64.
+type Float float64
+
+// NewFloat returns a Float.
+func NewFloat() Observable {
+	f := Float(0)
+	return &f
+}
+
+// String returns the float as a string.
+func (f *Float) String() string { return fmt.Sprintf("%g", f.Value()) }
+
+// Value returns the float's value.
+func (f *Float) Value() float64 { return float64(*f) }
+
+func (f *Float) Multiply(ratio float64) { *f *= Float(ratio) }
+
+func (f *Float) Add(other Observable) {
+	o := other.(*Float)
+	*f += *o
+}
+
+func (f *Float) Clear() { *f = 0 }
+
+func (f *Float) CopyFrom(other Observable) {
+	o := other.(*Float)
+	*f = *o
+}
+
+// A Clock tells the current time.
+type Clock interface {
+	Time() time.Time
+}
+
+type defaultClock int
+
+var defaultClockInstance defaultClock
+
+func (defaultClock) Time() time.Time { return time.Now() }
+
+// Information kept per level. Each level consists of a circular list of
+// observations. The start of the level may be derived from end and the
+// len(buckets) * sizeInMillis.
+type tsLevel struct {
+	oldest   int               // index to oldest bucketed Observable
+	newest   int               // index to newest bucketed Observable
+	end      time.Time         // end timestamp for this level
+	size     time.Duration     // duration of the bucketed Observable
+	buckets  []Observable      // collections of observations
+	provider func() Observable // used for creating new Observable
+}
+
+func (l *tsLevel) Clear() {
+	l.oldest = 0
+	l.newest = len(l.buckets) - 1
+	l.end = time.Time{}
+	for i := range l.buckets {
+		if l.buckets[i] != nil {
+			l.buckets[i].Clear()
+			l.buckets[i] = nil
+		}
+	}
+}
+
+func (l *tsLevel) InitLevel(size time.Duration, numBuckets int, f func() Observable) {
+	l.size = size
+	l.provider = f
+	l.buckets = make([]Observable, numBuckets)
+}
+
+// Keeps a sequence of levels. Each level is responsible for storing data at
+// a given resolution. For example, the first level stores data at a one
+// minute resolution while the second level stores data at a one hour
+// resolution.
+
+// Each level is represented by a sequence of buckets. Each bucket spans an
+// interval equal to the resolution of the level. New observations are added
+// to the last bucket.
+type timeSeries struct {
+	provider    func() Observable // make more Observable
+	numBuckets  int               // number of buckets in each level
+	levels      []*tsLevel        // levels of bucketed Observable
+	lastAdd     time.Time         // time of last Observable tracked
+	total       Observable        // convenient aggregation of all Observable
+	clock       Clock             // Clock for getting current time
+	pending     Observable        // observations not yet bucketed
+	pendingTime time.Time         // what time are we keeping in pending
+	dirty       bool              // if there are pending observations
+}
+
+// init initializes a level according to the supplied criteria.
+func (ts *timeSeries) init(resolutions []time.Duration, f func() Observable, numBuckets int, clock Clock) {
+	ts.provider = f
+	ts.numBuckets = numBuckets
+	ts.clock = clock
+	ts.levels = make([]*tsLevel, len(resolutions))
+
+	for i := range resolutions {
+		if i > 0 && resolutions[i-1] >= resolutions[i] {
+			log.Print("timeseries: resolutions must be monotonically increasing")
+			break
+		}
+		newLevel := new(tsLevel)
+		newLevel.InitLevel(resolutions[i], ts.numBuckets, ts.provider)
+		ts.levels[i] = newLevel
+	}
+
+	ts.Clear()
+}
+
+// Clear removes all observations from the time series.
+func (ts *timeSeries) Clear() {
+	ts.lastAdd = time.Time{}
+	ts.total = ts.resetObservation(ts.total)
+	ts.pending = ts.resetObservation(ts.pending)
+	ts.pendingTime = time.Time{}
+	ts.dirty = false
+
+	for i := range ts.levels {
+		ts.levels[i].Clear()
+	}
+}
+
+// Add records an observation at the current time.
+func (ts *timeSeries) Add(observation Observable) {
+	ts.AddWithTime(observation, ts.clock.Time())
+}
+
+// AddWithTime records an observation at the specified time.
+func (ts *timeSeries) AddWithTime(observation Observable, t time.Time) {
+
+	smallBucketDuration := ts.levels[0].size
+
+	if t.After(ts.lastAdd) {
+		ts.lastAdd = t
+	}
+
+	if t.After(ts.pendingTime) {
+		ts.advance(t)
+		ts.mergePendingUpdates()
+		ts.pendingTime = ts.levels[0].end
+		ts.pending.CopyFrom(observation)
+		ts.dirty = true
+	} else if t.After(ts.pendingTime.Add(-1 * smallBucketDuration)) {
+		// The observation is close enough to go into the pending bucket.
+		// This compensates for clock skewing and small scheduling delays
+		// by letting the update stay in the fast path.
+		ts.pending.Add(observation)
+		ts.dirty = true
+	} else {
+		ts.mergeValue(observation, t)
+	}
+}
+
+// mergeValue inserts the observation at the specified time in the past into all levels.
+func (ts *timeSeries) mergeValue(observation Observable, t time.Time) {
+	for _, level := range ts.levels {
+		index := (ts.numBuckets - 1) - int(level.end.Sub(t)/level.size)
+		if 0 <= index && index < ts.numBuckets {
+			bucketNumber := (level.oldest + index) % ts.numBuckets
+			if level.buckets[bucketNumber] == nil {
+				level.buckets[bucketNumber] = level.provider()
+			}
+			level.buckets[bucketNumber].Add(observation)
+		}
+	}
+	ts.total.Add(observation)
+}
+
+// mergePendingUpdates applies the pending updates into all levels.
+func (ts *timeSeries) mergePendingUpdates() {
+	if ts.dirty {
+		ts.mergeValue(ts.pending, ts.pendingTime)
+		ts.pending = ts.resetObservation(ts.pending)
+		ts.dirty = false
+	}
+}
+
+// advance cycles the buckets at each level until the latest bucket in
+// each level can hold the time specified.
+func (ts *timeSeries) advance(t time.Time) {
+	if !t.After(ts.levels[0].end) {
+		return
+	}
+	for i := 0; i < len(ts.levels); i++ {
+		level := ts.levels[i]
+		if !level.end.Before(t) {
+			break
+		}
+
+		// If the time is sufficiently far, just clear the level and advance
+		// directly.
+		if !t.Before(level.end.Add(level.size * time.Duration(ts.numBuckets))) {
+			for _, b := range level.buckets {
+				ts.resetObservation(b)
+			}
+			level.end = time.Unix(0, (t.UnixNano()/level.size.Nanoseconds())*level.size.Nanoseconds())
+		}
+
+		for t.After(level.end) {
+			level.end = level.end.Add(level.size)
+			level.newest = level.oldest
+			level.oldest = (level.oldest + 1) % ts.numBuckets
+			ts.resetObservation(level.buckets[level.newest])
+		}
+
+		t = level.end
+	}
+}
+
+// Latest returns the sum of the num latest buckets from the level.
+func (ts *timeSeries) Latest(level, num int) Observable {
+	now := ts.clock.Time()
+	if ts.levels[0].end.Before(now) {
+		ts.advance(now)
+	}
+
+	ts.mergePendingUpdates()
+
+	result := ts.provider()
+	l := ts.levels[level]
+	index := l.newest
+
+	for i := 0; i < num; i++ {
+		if l.buckets[index] != nil {
+			result.Add(l.buckets[index])
+		}
+		if index == 0 {
+			index = ts.numBuckets
+		}
+		index--
+	}
+
+	return result
+}
+
+// LatestBuckets returns a copy of the num latest buckets from level.
+func (ts *timeSeries) LatestBuckets(level, num int) []Observable {
+	if level < 0 || level > len(ts.levels) {
+		log.Print("timeseries: bad level argument: ", level)
+		return nil
+	}
+	if num < 0 || num >= ts.numBuckets {
+		log.Print("timeseries: bad num argument: ", num)
+		return nil
+	}
+
+	results := make([]Observable, num)
+	now := ts.clock.Time()
+	if ts.levels[0].end.Before(now) {
+		ts.advance(now)
+	}
+
+	ts.mergePendingUpdates()
+
+	l := ts.levels[level]
+	index := l.newest
+
+	for i := 0; i < num; i++ {
+		result := ts.provider()
+		results[i] = result
+		if l.buckets[index] != nil {
+			result.CopyFrom(l.buckets[index])
+		}
+
+		if index == 0 {
+			index = ts.numBuckets
+		}
+		index -= 1
+	}
+	return results
+}
+
+// ScaleBy updates observations by scaling by factor.
+func (ts *timeSeries) ScaleBy(factor float64) {
+	for _, l := range ts.levels {
+		for i := 0; i < ts.numBuckets; i++ {
+			l.buckets[i].Multiply(factor)
+		}
+	}
+
+	ts.total.Multiply(factor)
+	ts.pending.Multiply(factor)
+}
+
+// Range returns the sum of observations added over the specified time range.
+// If start or finish times don't fall on bucket boundaries of the same
+// level, then return values are approximate answers.
+func (ts *timeSeries) Range(start, finish time.Time) Observable {
+	return ts.ComputeRange(start, finish, 1)[0]
+}
+
+// Recent returns the sum of observations from the last delta.
+func (ts *timeSeries) Recent(delta time.Duration) Observable {
+	now := ts.clock.Time()
+	return ts.Range(now.Add(-delta), now)
+}
+
+// Total returns the total of all observations.
+func (ts *timeSeries) Total() Observable {
+	ts.mergePendingUpdates()
+	return ts.total
+}
+
+// ComputeRange computes a specified number of values into a slice using
+// the observations recorded over the specified time period. The return
+// values are approximate if the start or finish times don't fall on the
+// bucket boundaries at the same level or if the number of buckets spanning
+// the range is not an integral multiple of num.
+func (ts *timeSeries) ComputeRange(start, finish time.Time, num int) []Observable {
+	if start.After(finish) {
+		log.Printf("timeseries: start > finish, %v>%v", start, finish)
+		return nil
+	}
+
+	if num < 0 {
+		log.Printf("timeseries: num < 0, %v", num)
+		return nil
+	}
+
+	results := make([]Observable, num)
+
+	for _, l := range ts.levels {
+		if !start.Before(l.end.Add(-l.size * time.Duration(ts.numBuckets))) {
+			ts.extract(l, start, finish, num, results)
+			return results
+		}
+	}
+
+	// Failed to find a level that covers the desired range.  So just
+	// extract from the last level, even if it doesn't cover the entire
+	// desired range.
+	ts.extract(ts.levels[len(ts.levels)-1], start, finish, num, results)
+
+	return results
+}
+
+// RecentList returns the specified number of values in slice over the most
+// recent time period of the specified range.
+func (ts *timeSeries) RecentList(delta time.Duration, num int) []Observable {
+	if delta < 0 {
+		return nil
+	}
+	now := ts.clock.Time()
+	return ts.ComputeRange(now.Add(-delta), now, num)
+}
+
+// extract returns a slice of specified number of observations from a given
+// level over a given range.
+func (ts *timeSeries) extract(l *tsLevel, start, finish time.Time, num int, results []Observable) {
+	ts.mergePendingUpdates()
+
+	srcInterval := l.size
+	dstInterval := finish.Sub(start) / time.Duration(num)
+	dstStart := start
+	srcStart := l.end.Add(-srcInterval * time.Duration(ts.numBuckets))
+
+	srcIndex := 0
+
+	// Where should scanning start?
+	if dstStart.After(srcStart) {
+		advance := dstStart.Sub(srcStart) / srcInterval
+		srcIndex += int(advance)
+		srcStart = srcStart.Add(advance * srcInterval)
+	}
+
+	// The i'th value is computed as show below.
+	// interval = (finish/start)/num
+	// i'th value = sum of observation in range
+	//   [ start + i       * interval,
+	//     start + (i + 1) * interval )
+	for i := 0; i < num; i++ {
+		results[i] = ts.resetObservation(results[i])
+		dstEnd := dstStart.Add(dstInterval)
+		for srcIndex < ts.numBuckets && srcStart.Before(dstEnd) {
+			srcEnd := srcStart.Add(srcInterval)
+			if srcEnd.After(ts.lastAdd) {
+				srcEnd = ts.lastAdd
+			}
+
+			if !srcEnd.Before(dstStart) {
+				srcValue := l.buckets[(srcIndex+l.oldest)%ts.numBuckets]
+				if !srcStart.Before(dstStart) && !srcEnd.After(dstEnd) {
+					// dst completely contains src.
+					if srcValue != nil {
+						results[i].Add(srcValue)
+					}
+				} else {
+					// dst partially overlaps src.
+					overlapStart := maxTime(srcStart, dstStart)
+					overlapEnd := minTime(srcEnd, dstEnd)
+					base := srcEnd.Sub(srcStart)
+					fraction := overlapEnd.Sub(overlapStart).Seconds() / base.Seconds()
+
+					used := ts.provider()
+					if srcValue != nil {
+						used.CopyFrom(srcValue)
+					}
+					used.Multiply(fraction)
+					results[i].Add(used)
+				}
+
+				if srcEnd.After(dstEnd) {
+					break
+				}
+			}
+			srcIndex++
+			srcStart = srcStart.Add(srcInterval)
+		}
+		dstStart = dstStart.Add(dstInterval)
+	}
+}
+
+// resetObservation clears the content so the struct may be reused.
+func (ts *timeSeries) resetObservation(observation Observable) Observable {
+	if observation == nil {
+		observation = ts.provider()
+	} else {
+		observation.Clear()
+	}
+	return observation
+}
+
+// TimeSeries tracks data at granularities from 1 second to 16 weeks.
+type TimeSeries struct {
+	timeSeries
+}
+
+// NewTimeSeries creates a new TimeSeries using the function provided for creating new Observable.
+func NewTimeSeries(f func() Observable) *TimeSeries {
+	return NewTimeSeriesWithClock(f, defaultClockInstance)
+}
+
+// NewTimeSeriesWithClock creates a new TimeSeries using the function provided for creating new Observable and the clock for
+// assigning timestamps.
+func NewTimeSeriesWithClock(f func() Observable, clock Clock) *TimeSeries {
+	ts := new(TimeSeries)
+	ts.timeSeries.init(timeSeriesResolutions, f, timeSeriesNumBuckets, clock)
+	return ts
+}
+
+// MinuteHourSeries tracks data at granularities of 1 minute and 1 hour.
+type MinuteHourSeries struct {
+	timeSeries
+}
+
+// NewMinuteHourSeries creates a new MinuteHourSeries using the function provided for creating new Observable.
+func NewMinuteHourSeries(f func() Observable) *MinuteHourSeries {
+	return NewMinuteHourSeriesWithClock(f, defaultClockInstance)
+}
+
+// NewMinuteHourSeriesWithClock creates a new MinuteHourSeries using the function provided for creating new Observable and the clock for
+// assigning timestamps.
+func NewMinuteHourSeriesWithClock(f func() Observable, clock Clock) *MinuteHourSeries {
+	ts := new(MinuteHourSeries)
+	ts.timeSeries.init(minuteHourSeriesResolutions, f,
+		minuteHourSeriesNumBuckets, clock)
+	return ts
+}
+
+func (ts *MinuteHourSeries) Minute() Observable {
+	return ts.timeSeries.Latest(0, 60)
+}
+
+func (ts *MinuteHourSeries) Hour() Observable {
+	return ts.timeSeries.Latest(1, 60)
+}
+
+func minTime(a, b time.Time) time.Time {
+	if a.Before(b) {
+		return a
+	}
+	return b
+}
+
+func maxTime(a, b time.Time) time.Time {
+	if a.After(b) {
+		return a
+	}
+	return b
+}