document io

R=rsc
DELTA=44  (30 added, 4 deleted, 10 changed)
OCL=25819
CL=25835

src/lib/io/bytebuffer.go

@@ -4,15 +4,13 @@
 
 package io
 
-// Byte buffer for marshaling nested messages.
+// Simple byte buffer for marshaling data.
 
 import (
 	"io";
 	"os";
 )
 
-// A simple implementation of the io.Read and io.Write interfaces.
-// A newly allocated ByteBuffer is ready to use.
 
 // TODO(r): Do better memory management.
 
@@ -24,6 +22,9 @@ func bytecopy(dst []byte, doff int, src []byte, soff int, count int) {
 	}
 }
 
+// A ByteBuffer is a simple implementation of the io.Read and io.Write interfaces
+// connected to a buffer of bytes.
+// The zero value for ByteBuffer is an empty buffer ready to use.
 type ByteBuffer struct {
 	buf	[]byte;
 	off	int;	// Read from here
@@ -31,11 +32,14 @@ type ByteBuffer struct {
 	cap	int;
 }
 
+// Reset resets the buffer so it has no content.
 func (b *ByteBuffer) Reset() {
 	b.off = 0;
 	b.len = 0;
 }
 
+// Write appends the contents of p to the buffer.  The return
+// value is the length of p; err is always nil.
 func (b *ByteBuffer) Write(p []byte) (n int, err *os.Error) {
 	plen := len(p);
 	if len(b.buf) == 0 {
@@ -54,6 +58,8 @@ func (b *ByteBuffer) Write(p []byte) (n int, err *os.Error) {
 	return plen, nil;
 }
 
+// Read reads the next len(p) bytes from the buffer or until the buffer
+// is drained.  The return value is the number of bytes read; err is always nil.
 func (b *ByteBuffer) Read(p []byte) (n int, err *os.Error) {
 	plen := len(p);
 	if len(b.buf) == 0 {
@@ -71,22 +77,23 @@ func (b *ByteBuffer) Read(p []byte) (n int, err *os.Error) {
 	return plen, nil;
 }
 
+// Len returns the length of the underlying buffer.
 func (b *ByteBuffer) Len() int {
 	return b.len
 }
 
+// Off returns the location within the buffer of the next byte to be read.
 func (b *ByteBuffer) Off() int {
 	return b.off
 }
 
+// Data returns the contents of the unread portion of the buffer.
 func (b *ByteBuffer) Data() []byte {
 	return b.buf[b.off:b.len]
 }
 
-func (b *ByteBuffer) AllData() []byte {
-	return b.buf[0:b.len]
-}
-
+// NewByteBufferFromArray creates and initializes a new ByteBuffer
+// with buf as its initial contents.
 func NewByteBufferFromArray(buf []byte) *ByteBuffer {
 	b := new(ByteBuffer);
 	b.buf = buf;

src/lib/io/io.go

@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// This package provides basic interfaces to I/O primitives.
+// Its primary job is to wrap existing implementations of such primitives,
+// such as those in package os, into shared public interfaces that
+// abstract the functionality.
+// It also provides buffering primitives and some other basic operations.
 package io
 
 import (
@@ -9,35 +14,43 @@ import (
 	"syscall";
 )
 
+// ErrEOF is the error returned by Readn and Copyn when they encounter EOF.
 var ErrEOF = os.NewError("EOF")
 
+// Read is the interface that wraps the basic Read method.
 type Read interface {
 	Read(p []byte) (n int, err *os.Error);
 }
 
+// Write is the interface that wraps the basic Write method.
 type Write interface {
 	Write(p []byte) (n int, err *os.Error);
 }
 
+// Close is the interface that wraps the basic Close method.
 type Close interface {
 	Close() *os.Error;
 }
 
+// ReadWrite is the interface that groups the basic Read and Write methods.
 type ReadWrite interface {
 	Read;
 	Write;
 }
 
+// ReadClose is the interface that groups the basic Read and Close methods.
 type ReadClose interface {
 	Read;
 	Close;
 }
 
+// WriteClose is the interface that groups the basic Write and Close methods.
 type WriteClose interface {
 	Write;
 	Close;
 }
 
+// ReadWriteClose is the interface that groups the basic Read, Write and Close methods.
 type ReadWriteClose interface {
 	Read;
 	Write;
@@ -53,11 +66,12 @@ func StringBytes(s string) []byte {
 	return b;
 }
 
+// WriteString writes the contents of the string s to w, which accepts an array of bytes.
 func WriteString(w Write, s string) (n int, err *os.Error) {
 	return w.Write(StringBytes(s))
 }
 
-// Read until buffer is full, EOF, or error
+// Readn reads r until the buffer buf is full, or until EOF or error.
 func Readn(r Read, buf []byte) (n int, err *os.Error) {
 	n = 0;
 	for n < len(buf) {
@@ -86,6 +100,8 @@ func (fr *fullRead) Read(p []byte) (n int, err *os.Error) {
 	return n, err
 }
 
+// MakeFullReader takes r, an implementation of Read, and returns an object
+// that still implements Read but always calls Readn underneath.
 func MakeFullReader(r Read) Read {
 	if fr, ok := r.(*fullRead); ok {
 		// already a fullRead
@@ -94,8 +110,8 @@ func MakeFullReader(r Read) Read {
 	return &fullRead{r}
 }
 
-// Copies n bytes (or until EOF is reached) from src to dst.
-// Returns the number of bytes copied and the error, if any.
+// Copy n copies n bytes (or until EOF is reached) from src to dst.
+// It returns the number of bytes copied and the error, if any.
 func Copyn(src Read, dst Write, n int64) (written int64, err *os.Error) {
 	buf := make([]byte, 32*1024);
 	for written < n {
@@ -130,8 +146,8 @@ func Copyn(src Read, dst Write, n int64) (written int64, err *os.Error) {
 	return written, err
 }
 
-// Copies from src to dst until EOF is reached.
-// Returns the number of bytes copied and the error, if any.
+// Copy copies from src to dst until EOF is reached.
+// It returns the number of bytes copied and the error, if any.
 func Copy(src Read, dst Write) (written int64, err *os.Error) {
 	buf := make([]byte, 32*1024);
 	for {

src/lib/io/pipe.go

@@ -169,7 +169,10 @@ func (w *pipeWrite) finish() {
 	w.Close();
 }
 
-// Create a synchronous in-memory pipe.
+// Pipe creates a synchronous in-memory pipe.
+// Used to connect code expecting an io.Read
+// with code expecting an io.Write.
+//
 // Reads on one end are matched by writes on the other.
 // Writes don't complete until all the data has been
 // written or the read end is closed.  Reads return