blob: a67e7435133c14eee30d8b23f8f2607e1e6bc288 [file] [log] [blame]
// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stddef.h>
#include <algorithm>
#include <iosfwd>
#include <iterator>
#include <string>
#include <utility>
#include <vector>
#include "base/logging.h"
#include "base/strings/string_piece.h"
#include "net/tools/balsa/balsa_enums.h"
#include "net/tools/balsa/string_piece_utils.h"
namespace net {
// Note that -no- char* returned by any function in this
// file is null-terminated.
// This class exists to service the specific needs of BalsaHeaders.
// Functional goals:
// 1) provide a backing-store for all of the StringPieces that BalsaHeaders
// returns. Every StringPiece returned from BalsaHeaders should remain
// valid until the BalsaHeader's object is cleared, or the header-line is
// erased.
// 2) provide a backing-store for BalsaFrame, which requires contiguous memory
// for its fast-path parsing functions. Note that the cost of copying is
// less than the cost of requiring the parser to do slow-path parsing, as
// it would have to check for bounds every byte, instead of every 16 bytes.
// This class is optimized for the case where headers are stored in one of two
// buffers. It doesn't make a lot of effort to densely pack memory-- in fact,
// it -may- be somewhat memory inefficient. This possible inefficiency allows a
// certain simplicity of implementation and speed which makes it worthwhile.
// If, in the future, better memory density is required, it should be possible
// to reuse the abstraction presented by this object to achieve those goals.
// In the most common use-case, this memory inefficiency should be relatively
// small.
// Alternate implementations of BalsaBuffer may include:
// - vector of strings, one per header line (similar to HTTPHeaders)
// - densely packed strings:
// - keep a sorted array/map of free-space linked lists or numbers.
// - use the entry that most closely first your needs.
// - at this point, perhaps just use a vector of strings, and let
// the allocator do the right thing.
class BalsaBuffer {
static const size_t kDefaultBlocksize = 4096;
// We have two friends here. These exist as friends as we
// want to allow access to the constructors for the test
// class and the Balsa* classes. We put this into the
// header file as we want this class to be inlined into the
// BalsaHeaders implementation, yet be testable.
friend class BalsaBufferTestSpouse;
friend class BalsaHeaders;
friend class BalsaBufferTest;
// The BufferBlock is a structure used internally by the
// BalsaBuffer class to store the base buffer pointers to
// each block, as well as the important metadata for buffer
// sizes and bytes free.
struct BufferBlock {
char* buffer;
size_t buffer_size;
size_t bytes_free;
size_t bytes_used() const {
return buffer_size - bytes_free;
char* start_of_unused_bytes() const {
return buffer + bytes_used();
BufferBlock() : buffer(NULL), buffer_size(0), bytes_free(0) {}
~BufferBlock() {}
BufferBlock(char* buf, size_t size, size_t free) :
buffer(buf), buffer_size(size), bytes_free(free) {}
// Yes we want this to be copyable (it gets stuck into vectors).
// For this reason, we don't use scoped ptrs, etc. here-- it
// is more efficient to manage this memory externally to this
// object.
typedef std::vector<BufferBlock> Blocks;
// Returns the total amount of memory used by the buffer blocks.
size_t GetTotalBufferBlockSize() const;
const char* GetPtr(Blocks::size_type block_idx) const {
DCHECK_LT(block_idx, blocks_.size())
<< block_idx << ", " << blocks_.size();
return blocks_[block_idx].buffer;
char* GetPtr(Blocks::size_type block_idx) {
DCHECK_LT(block_idx, blocks_.size())
<< block_idx << ", " << blocks_.size();
return blocks_[block_idx].buffer;
// This function is different from Write(), as it ensures that the data
// stored via subsequent calls to this function are all contiguous (and in
// the order in which these writes happened). This is essentially the same
// as a string append.
// You may call this function at any time between object
// construction/Clear(), and the calling of the
// NoMoreWriteToContiguousBuffer() function.
// You must not call this function after the NoMoreWriteToContiguousBuffer()
// function is called, unless a Clear() has been called since.
// If you do, the program will abort().
// This condition is placed upon this code so that calls to Write() can
// append to the buffer in the first block safely, and without invaliding
// the StringPiece which it returns.
// This function's main intended user is the BalsaFrame class, which,
// for reasons of efficiency, requires that the buffer from which it parses
// the headers be contiguous.
void WriteToContiguousBuffer(const base::StringPiece& sp);
void NoMoreWriteToContiguousBuffer() {
can_write_to_contiguous_buffer_ = false;
// Takes a StringPiece and writes it to "permanent" storage, then returns a
// StringPiece which points to that data. If block_idx != NULL, it will be
// assigned the index of the block into which the data was stored.
// Note that the 'permanent' storage in which it stores data may be in
// the first block IFF the NoMoreWriteToContiguousBuffer function has
// been called since the last Clear/Construction.
base::StringPiece Write(const base::StringPiece& sp,
Blocks::size_type* block_buffer_idx);
// Reserves "permanent" storage of the size indicated. Returns a pointer to
// the beginning of that storage, and assigns the index of the block used to
// block_buffer_idx. This function uses the first block IFF the
// NoMoreWriteToContiguousBuffer function has been called since the last
// Clear/Construction.
char* Reserve(size_t size, Blocks::size_type* block_buffer_idx);
void Clear();
void Swap(BalsaBuffer* b);
void CopyFrom(const BalsaBuffer& b);
const char* StartOfFirstBlock() const {
return blocks_[0].buffer;
const char* EndOfFirstBlock() const {
return blocks_[0].buffer + blocks_[0].bytes_used();
bool can_write_to_contiguous_buffer() const {
return can_write_to_contiguous_buffer_;
size_t blocksize() const { return blocksize_; }
Blocks::size_type num_blocks() const { return blocks_.size(); }
size_t buffer_size(size_t idx) const { return blocks_[idx].buffer_size; }
size_t bytes_used(size_t idx) const { return blocks_[idx].bytes_used(); }
explicit BalsaBuffer(size_t blocksize);
BufferBlock AllocBlock();
BufferBlock AllocCustomBlock(size_t blocksize);
BufferBlock CopyBlock(const BufferBlock& b);
// Cleans up the object.
// The block at start_idx, and all subsequent blocks
// will be cleared and have associated memory deleted.
void CleanupBlocksStartingFrom(Blocks::size_type start_idx);
// A container of BufferBlocks
Blocks blocks_;
// The default allocation size for a block.
// In general, blocksize_ bytes will be allocated for
// each buffer.
size_t blocksize_;
// If set to true, then the first block cannot be used for Write() calls as
// the WriteToContiguous... function will modify the base pointer for this
// block, and the Write() calls need to be sure that the base pointer will
// not be changing in order to provide the user with StringPieces which
// continue to be valid.
bool can_write_to_contiguous_buffer_;
// All of the functions in the BalsaHeaders class use string pieces, by either
// using the StringPiece class, or giving an explicit size and char* (as these
// are the native representation for these string pieces).
// This is done for several reasons.
// 1) This minimizes copying/allocation/deallocation as compared to using
// string parameters
// 2) This reduces the number of strlen() calls done (as the length of any
// string passed in is relatively likely to be known at compile time, and for
// those strings passed back we obviate the need for a strlen() to determine
// the size of new storage allocations if a new allocation is required.
// 3) This class attempts to store all of its data in two linear buffers in
// order to enhance the speed of parsing and writing out to a buffer. As a
// result, many string pieces are -not- terminated by '\0', and are not
// c-strings. Since this is the case, we must delineate the length of the
// string explicitly via a length.
// WARNING: The side effect of using StringPiece is that if the underlying
// buffer changes (due to modifying the headers) the StringPieces which point
// to the data which was modified, may now contain "garbage", and should not
// be dereferenced.
// For example, If you fetch some component of the first-line, (request or
// response), and then you modify the first line, the StringPieces you
// originally received from the original first-line may no longer be valid).
// StringPieces pointing to pieces of header lines which have not been
// erased() or modified should be valid until the object is cleared or
// destroyed.
class BalsaHeaders {
struct HeaderLineDescription {
HeaderLineDescription(size_t first_character_index,
size_t key_end_index,
size_t value_begin_index,
size_t last_character_index,
size_t buffer_base_index) :
skip(false) {}
HeaderLineDescription() :
skip(false) {}
size_t first_char_idx;
size_t key_end_idx;
size_t value_begin_idx;
size_t last_char_idx;
BalsaBuffer::Blocks::size_type buffer_base_idx;
bool skip;
typedef std::vector<base::StringPiece> HeaderTokenList;
friend bool ParseHTTPFirstLine(const char* begin,
const char* end,
bool is_request,
size_t max_request_uri_length,
BalsaHeaders* headers,
BalsaFrameEnums::ErrorCode* error_code);
typedef std::vector<HeaderLineDescription> HeaderLines;
// Why these base classes (iterator_base, reverse_iterator_base)? Well, if
// we do want to export both iterator and const_iterator types (currently we
// only have const_iterator), then this is useful to avoid code duplication.
// Additionally, having this base class makes comparisons of iterators of
// different types (they're different types to ensure that operator= and
// constructors do not work in the places where they're expected to not work)
// work properly. There could be as many as 4 iterator types, all based on
// the same data as iterator_base... so it makes sense to simply have some
// base classes.
class iterator_base {
friend class BalsaHeaders;
friend class reverse_iterator_base;
typedef std::pair<base::StringPiece, base::StringPiece> StringPiecePair;
typedef StringPiecePair value_type;
typedef value_type& reference;
typedef value_type* pointer;
typedef std::forward_iterator_tag iterator_category;
typedef ptrdiff_t difference_type;
typedef iterator_base self;
// default constructor.
// copy constructor.
iterator_base(const iterator_base& it);
reference operator*() const {
return Lookup(idx_);
pointer operator->() const {
return &(this->operator*());
bool operator==(const self& it) const {
return idx_ == it.idx_;
bool operator<(const self& it) const {
return idx_ < it.idx_;
bool operator<=(const self& it) const {
return idx_ <= it.idx_;
bool operator!=(const self& it) const {
return !(*this == it);
bool operator>(const self& it) const {
return it < *this;
bool operator>=(const self& it) const {
return it <= *this;
// This mainly exists so that we can have interesting output for
// unittesting. The EXPECT_EQ, EXPECT_NE functions require that
// operator<< work for the classes it sees. It would be better if there
// was an additional traits-like system for the gUnit output... but oh
// well.
std::ostream& operator<<(std::ostream& os) const;
iterator_base(const BalsaHeaders* headers, HeaderLines::size_type index);
void increment() {
const HeaderLines& header_lines = headers_->header_lines_;
const HeaderLines::size_type header_lines_size = header_lines.size();
const HeaderLines::size_type original_idx = idx_;
do {
} while (idx_ < header_lines_size && header_lines[idx_].skip == true);
// The condition below exists so that ++(end() - 1) == end(), even
// if there are only 'skip == true' elements between the end() iterator
// and the end of the vector of HeaderLineDescriptions.
// TODO(fenix): refactor this list so that we don't have to do
// linear scanning through skipped headers (and this condition is
// then unnecessary)
if (idx_ == header_lines_size) {
idx_ = original_idx + 1;
void decrement() {
const HeaderLines& header_lines = headers_->header_lines_;
const HeaderLines::size_type header_lines_size = header_lines.size();
const HeaderLines::size_type original_idx = idx_;
do {
} while (idx_ < header_lines_size && header_lines[idx_].skip == true);
// The condition below exists so that --(rbegin() + 1) == rbegin(), even
// if there are only 'skip == true' elements between the rbegin() iterator
// and the beginning of the vector of HeaderLineDescriptions.
// TODO(fenix): refactor this list so that we don't have to do
// linear scanning through skipped headers (and this condition is
// then unnecessary)
if (idx_ > header_lines_size) {
idx_ = original_idx - 1;
reference Lookup(HeaderLines::size_type index) const {
DCHECK_LT(index, headers_->header_lines_.size());
const HeaderLineDescription& line = headers_->header_lines_[index];
const char* stream_begin = headers_->GetPtr(line.buffer_base_idx);
value_ = value_type(
base::StringPiece(stream_begin + line.first_char_idx,
line.key_end_idx - line.first_char_idx),
base::StringPiece(stream_begin + line.value_begin_idx,
line.last_char_idx - line.value_begin_idx));
DCHECK_GE(line.key_end_idx, line.first_char_idx);
DCHECK_GE(line.last_char_idx, line.value_begin_idx);
return value_;
const BalsaHeaders* headers_;
HeaderLines::size_type idx_;
mutable StringPiecePair value_;
class reverse_iterator_base : public iterator_base {
typedef reverse_iterator_base self;
typedef iterator_base::reference reference;
typedef iterator_base::pointer pointer;
using iterator_base::headers_;
using iterator_base::idx_;
reverse_iterator_base() : iterator_base() {}
// This constructor is no explicit purposely.
reverse_iterator_base(const iterator_base& it) : // NOLINT
iterator_base(it) {
self& operator=(const iterator_base& it) {
idx_ = it.idx_;
headers_ = it.headers_;
return *this;
self& operator=(const reverse_iterator_base& it) {
idx_ = it.idx_;
headers_ = it.headers_;
return *this;
reference operator*() const {
return Lookup(idx_ - 1);
pointer operator->() const {
return &(this->operator*());
reverse_iterator_base(const reverse_iterator_base& it) :
iterator_base(it) { }
void increment() {
void decrement() {
reverse_iterator_base(const BalsaHeaders* headers,
HeaderLines::size_type index) :
iterator_base(headers, index) {}
class const_header_lines_iterator : public iterator_base {
friend class BalsaHeaders;
typedef const_header_lines_iterator self;
const_header_lines_iterator() : iterator_base() {}
const_header_lines_iterator(const const_header_lines_iterator& it) :
iterator_base(it.headers_, it.idx_) {}
self& operator++() {
return *this;
self& operator--() {
return *this;
const_header_lines_iterator(const BalsaHeaders* headers,
HeaderLines::size_type index) :
iterator_base(headers, index) {}
class const_reverse_header_lines_iterator : public reverse_iterator_base {
typedef const_reverse_header_lines_iterator self;
const_reverse_header_lines_iterator() : reverse_iterator_base() {}
const const_header_lines_iterator& it) :
reverse_iterator_base(it.headers_, it.idx_) {}
const const_reverse_header_lines_iterator& it) :
reverse_iterator_base(it.headers_, it.idx_) {}
const_header_lines_iterator base() {
return const_header_lines_iterator(headers_, idx_);
self& operator++() {
return *this;
self& operator--() {
return *this;
const_reverse_header_lines_iterator(const BalsaHeaders* headers,
HeaderLines::size_type index) :
reverse_iterator_base(headers, index) {}
friend class BalsaHeaders;
// An iterator that only stops at lines with a particular key.
// See also GetIteratorForKey.
// Check against header_lines_key_end() to determine when iteration is
// finished. header_lines_end() will also work.
class const_header_lines_key_iterator : public iterator_base {
friend class BalsaHeaders;
typedef const_header_lines_key_iterator self;
const_header_lines_key_iterator(const const_header_lines_key_iterator&);
self& operator++() {
do {
} while (!AtEnd() &&
!base::EqualsCaseInsensitiveASCII(key_, (**this).first));
return *this;
void operator++(int ignore) {
// Only forward-iteration makes sense, so no operator-- defined.
const_header_lines_key_iterator(const BalsaHeaders* headers,
HeaderLines::size_type index,
const base::StringPiece& key);
// Should only be used for creating an end iterator.
const_header_lines_key_iterator(const BalsaHeaders* headers,
HeaderLines::size_type index);
bool AtEnd() const {
return *this >= headers_->header_lines_end();
base::StringPiece key_;
// TODO(fenix): Revisit the amount of bytes initially allocated to the second
// block of the balsa_buffer_. It may make sense to pre-allocate some amount
// (roughly the amount we'd append in new headers such as X-User-Ip, etc.)
const_header_lines_iterator header_lines_begin() {
return HeaderLinesBeginHelper<const_header_lines_iterator>();
const_header_lines_iterator header_lines_begin() const {
return HeaderLinesBeginHelper<const_header_lines_iterator>();
const_header_lines_iterator header_lines_end() {
return HeaderLinesEndHelper<const_header_lines_iterator>();
const_header_lines_iterator header_lines_end() const {
return HeaderLinesEndHelper<const_header_lines_iterator>();
const_reverse_header_lines_iterator header_lines_rbegin() {
return const_reverse_header_lines_iterator(header_lines_end());
const_reverse_header_lines_iterator header_lines_rbegin() const {
return const_reverse_header_lines_iterator(header_lines_end());
const_reverse_header_lines_iterator header_lines_rend() {
return const_reverse_header_lines_iterator(header_lines_begin());
const_reverse_header_lines_iterator header_lines_rend() const {
return const_reverse_header_lines_iterator(header_lines_begin());
const_header_lines_key_iterator header_lines_key_end() const {
return HeaderLinesEndHelper<const_header_lines_key_iterator>();
void erase(const const_header_lines_iterator& it) {
DCHECK_EQ(it.headers_, this);
DCHECK_LT(it.idx_, header_lines_.size());
DCHECK_GE(it.idx_, 0u);
header_lines_[it.idx_].skip = true;
void Clear();
void Swap(BalsaHeaders* other);
void CopyFrom(const BalsaHeaders& other);
void HackHeader(const base::StringPiece& key, const base::StringPiece& value);
// Same as AppendToHeader, except that it will attempt to preserve
// header ordering.
// Note that this will always append to an existing header, if available,
// without moving the header around, or collapsing multiple header lines
// with the same key together. For this reason, it only 'attempts' to
// preserve header ordering.
// TODO(fenix): remove this function and rename all occurances
// of it in the code to AppendToHeader when the condition above
// has been satisified.
void HackAppendToHeader(const base::StringPiece& key,
const base::StringPiece& value);
// Replaces header entries with key 'key' if they exist, or appends
// a new header if none exist. See 'AppendHeader' below for additional
// comments about ContentLength and TransferEncoding headers. Note that this
// will allocate new storage every time that it is called.
// TODO(fenix): modify this function to reuse existing storage
// if it is available.
void ReplaceOrAppendHeader(const base::StringPiece& key,
const base::StringPiece& value);
// Append a new header entry to the header object. Clients who wish to append
// Content-Length header should use SetContentLength() method instead of
// adding the content length header using AppendHeader (manually adding the
// content length header will not update the content_length_ and
// content_length_status_ values).
// Similarly, clients who wish to add or remove the transfer encoding header
// in order to apply or remove chunked encoding should use SetChunkEncoding()
// instead.
void AppendHeader(const base::StringPiece& key,
const base::StringPiece& value);
// Appends ',value' to an existing header named 'key'. If no header with the
// correct key exists, it will call AppendHeader(key, value). Calling this
// function on a key which exists several times in the headers will produce
// unpredictable results.
void AppendToHeader(const base::StringPiece& key,
const base::StringPiece& value);
// Prepends 'value,' to an existing header named 'key'. If no header with the
// correct key exists, it will call AppendHeader(key, value). Calling this
// function on a key which exists several times in the headers will produce
// unpredictable results.
void PrependToHeader(const base::StringPiece& key,
const base::StringPiece& value);
const base::StringPiece GetHeader(const base::StringPiece& key) const;
// Iterates over all currently valid header lines, appending their
// values into the vector 'out', in top-to-bottom order.
// Header-lines which have been erased are not currently valid, and
// will not have their values appended. Empty values will be
// represented as empty string. If 'key' doesn't exist in the headers at
// all, out will not be changed. We do not clear the vector out
// before adding new entries. If there are header lines with matching
// key but empty value then they are also added to the vector out.
// (Basically empty values are not treated in any special manner).
// Example:
// Input header:
// "GET / HTTP/1.0\r\n"
// "key1: v1\r\n"
// "key1: \r\n"
// "key1:\r\n"
// "key1: v1\r\n"
// "key1:v2\r\n"
// vector out is initially: ["foo"]
// vector out after GetAllOfHeader("key1", &out) is:
// ["foo", "v1", "", "", "v2", "v1", "v2"]
void GetAllOfHeader(const base::StringPiece& key,
std::vector<base::StringPiece>* out) const;
// Joins all values for key into a comma-separated string in out.
// More efficient than calling JoinStrings on result of GetAllOfHeader if
// you don't need the intermediate vector<StringPiece>.
void GetAllOfHeaderAsString(const base::StringPiece& key,
std::string* out) const;
// Returns true if RFC 2616 Section 14 indicates that header can
// have multiple values.
static bool IsMultivaluedHeader(const base::StringPiece& header);
// Determine if a given header is present.
inline bool HasHeader(const base::StringPiece& key) const {
return (GetConstHeaderLinesIterator(key, header_lines_.begin()) !=
// Returns true iff any header 'key' exists with non-empty value.
bool HasNonEmptyHeader(const base::StringPiece& key) const;
const_header_lines_iterator GetHeaderPosition(
const base::StringPiece& key) const;
// Returns a forward-only iterator that only stops at lines matching key.
// String backing 'key' must remain valid for lifetime of iterator.
// Check returned iterator against header_lines_key_end() to determine when
// iteration is finished.
const_header_lines_key_iterator GetIteratorForKey(
const base::StringPiece& key) const;
void RemoveAllOfHeader(const base::StringPiece& key);
// Removes all headers starting with 'key' [case insensitive]
void RemoveAllHeadersWithPrefix(const base::StringPiece& key);
// Returns the lower bound of memory used by this header object, including
// all internal buffers and data structure. Some of the memory used cannot be
// directly measure. For example, memory used for bookkeeping by standard
// containers.
size_t GetMemoryUsedLowerBound() const;
// Returns the upper bound on the required buffer space to fully write out
// the header object (this include the first line, all header lines, and the
// final CRLF that marks the ending of the header).
size_t GetSizeForWriteBuffer() const;
// The following WriteHeader* methods are template member functions that
// place one requirement on the Buffer class: it must implement a Write
// method that takes a pointer and a length. The buffer passed in is not
// required to be stretchable. For non-stretchable buffers, the user must
// call GetSizeForWriteBuffer() to find out the upper bound on the output
// buffer space required to make sure that the entire header is serialized.
// BalsaHeaders will not check that there is adequate space in the buffer
// object during the write.
// Writes the entire header and the final CRLF that marks the end of the HTTP
// header section to the buffer. After this method returns, no more header
// data should be written to the buffer.
template <typename Buffer>
void WriteHeaderAndEndingToBuffer(Buffer* buffer) const {
// Writes the final CRLF to the buffer to terminate the HTTP header section.
// After this method returns, no more header data should be written to the
// buffer.
template <typename Buffer>
static void WriteHeaderEndingToBuffer(Buffer* buffer) {
buffer->Write("\r\n", 2);
// Writes the entire header to the buffer without the CRLF that terminates
// the HTTP header. This lets users append additional header lines using
// WriteHeaderLineToBuffer and then terminate the header with
// WriteHeaderEndingToBuffer as the header is serialized to the
// buffer, without having to first copy the header.
template <typename Buffer>
void WriteToBuffer(Buffer* buffer) const {
// write the first line.
const size_t firstline_len = whitespace_4_idx_ - non_whitespace_1_idx_;
const char* stream_begin = GetPtr(firstline_buffer_base_idx_);
buffer->Write(stream_begin + non_whitespace_1_idx_, firstline_len);
buffer->Write("\r\n", 2);
const HeaderLines::size_type end = header_lines_.size();
for (HeaderLines::size_type i = 0; i < end; ++i) {
const HeaderLineDescription& line = header_lines_[i];
if (line.skip) {
const char* line_ptr = GetPtr(line.buffer_base_idx);
base::StringPiece(line_ptr + line.first_char_idx,
line.key_end_idx - line.first_char_idx),
base::StringPiece(line_ptr + line.value_begin_idx,
line.last_char_idx - line.value_begin_idx));
// Takes a header line in the form of a key/value pair and append it to the
// buffer. This function should be called after WriteToBuffer to
// append additional header lines to the header without copying the header.
// When the user is done with appending to the buffer,
// WriteHeaderEndingToBuffer must be used to terminate the HTTP
// header in the buffer. This method is a no-op if key is empty.
template <typename Buffer>
static void WriteHeaderLineToBuffer(Buffer* buffer,
const base::StringPiece& key,
const base::StringPiece& value) {
// if the key is empty, we don't want to write the rest because it
// will not be a well-formed header line.
if (!key.empty()) {
buffer->Write(, key.size());
buffer->Write(": ", 2);
buffer->Write(, value.size());
buffer->Write("\r\n", 2);
// Dump the textural representation of the header object to a string, which
// is suitable for writing out to logs. All CRLF will be printed out as \n.
// This function can be called on a header object in any state. The header
// content is appended to the string; the original content is not cleared.
void DumpHeadersToString(std::string* str) const;
// Calls DumpHeadersToString to dump the textural representation of the header
// object to a string. Raw header data will be printed out if the header
// object is not completely parsed, e.g., when there was an error in the
// middle of parsing.
void DumpToString(std::string* str) const;
const base::StringPiece first_line() const {
DCHECK_GE(whitespace_4_idx_, non_whitespace_1_idx_);
return base::StringPiece(BeginningOfFirstLine() + non_whitespace_1_idx_,
whitespace_4_idx_ - non_whitespace_1_idx_);
// Returns the parsed value of the response code if it has been parsed.
// Guaranteed to return 0 when unparsed (though it is a much better idea to
// verify that the BalsaFrame had no errors while parsing).
// This may return response codes which are outside the normal bounds of
// HTTP response codes-- it is up to the user of this class to ensure that
// the response code is one which is interpretable.
size_t parsed_response_code() const { return parsed_response_code_; }
const base::StringPiece request_method() const {
DCHECK_GE(whitespace_2_idx_, non_whitespace_1_idx_);
return base::StringPiece(BeginningOfFirstLine() + non_whitespace_1_idx_,
whitespace_2_idx_ - non_whitespace_1_idx_);
const base::StringPiece response_version() const {
// Note: There is no difference between request_method() and
// response_version(). They both could be called
// GetFirstTokenFromFirstline()... but that wouldn't be anywhere near as
// descriptive.
return request_method();
const base::StringPiece request_uri() const {
DCHECK_GE(whitespace_3_idx_, non_whitespace_2_idx_);
return base::StringPiece(BeginningOfFirstLine() + non_whitespace_2_idx_,
whitespace_3_idx_ - non_whitespace_2_idx_);
const base::StringPiece response_code() const {
// Note: There is no difference between request_uri() and response_code().
// They both could be called GetSecondtTokenFromFirstline(), but, as noted
// in an earlier comment, that wouldn't be as descriptive.
return request_uri();
const base::StringPiece request_version() const {
DCHECK_GE(whitespace_4_idx_, non_whitespace_3_idx_);
return base::StringPiece(BeginningOfFirstLine() + non_whitespace_3_idx_,
whitespace_4_idx_ - non_whitespace_3_idx_);
const base::StringPiece response_reason_phrase() const {
// Note: There is no difference between request_version() and
// response_reason_phrase(). They both could be called
// GetThirdTokenFromFirstline(), but, as noted in an earlier comment, that
// wouldn't be as descriptive.
return request_version();
// Note that SetFirstLine will not update the internal indices for the
// various bits of the first-line (and may set them all to zero).
// If you'd like to use the accessors for the various bits of the firstline,
// then you should use the Set* functions, or SetFirstlineFromStringPieces,
// below, instead.
void SetFirstlineFromStringPieces(const base::StringPiece& firstline_a,
const base::StringPiece& firstline_b,
const base::StringPiece& firstline_c);
void SetRequestFirstlineFromStringPieces(const base::StringPiece& method,
const base::StringPiece& uri,
const base::StringPiece& version) {
SetFirstlineFromStringPieces(method, uri, version);
void SetResponseFirstlineFromStringPieces(
const base::StringPiece& version,
const base::StringPiece& code,
const base::StringPiece& reason_phrase) {
SetFirstlineFromStringPieces(version, code, reason_phrase);
// These functions are exactly the same, except that their names are
// different. This is done so that the code using this class is more
// expressive.
void SetRequestMethod(const base::StringPiece& method);
void SetResponseVersion(const base::StringPiece& version);
void SetRequestUri(const base::StringPiece& uri);
void SetResponseCode(const base::StringPiece& code);
void set_parsed_response_code(size_t parsed_response_code) {
parsed_response_code_ = parsed_response_code;
void SetParsedResponseCodeAndUpdateFirstline(size_t parsed_response_code);
// These functions are exactly the same, except that their names are
// different. This is done so that the code using this class is more
// expressive.
void SetRequestVersion(const base::StringPiece& version);
void SetResponseReasonPhrase(const base::StringPiece& reason_phrase);
// The biggest problem with SetFirstLine is that we don't want to use a
// separate buffer for it. The second biggest problem with it is that the
// first biggest problem requires that we store offsets into a buffer instead
// of pointers into a buffer. Cuteness aside, SetFirstLine doesn't parse
// the individual fields of the firstline, and so accessors to those fields
// will not work properly after calling SetFirstLine. If you want those
// accessors to work, use the Set* functions above this one.
// SetFirstLine is stuff useful, however, if all you care about is correct
// serialization with the rest of the header object.
void SetFirstLine(const base::StringPiece& line);
// Simple accessors to some of the internal state
bool transfer_encoding_is_chunked() const {
return transfer_encoding_is_chunked_;
static bool ResponseCodeImpliesNoBody(size_t code) {
// From HTTP spec section 6.1.1 all 1xx responses must not have a body,
// as well as 204 No Content and 304 Not Modified.
return ((code >= 100) && (code <= 199)) || (code == 204) || (code == 304);
// Note: never check this for requests. Nothing bad will happen if you do,
// but spec does not allow requests framed by connection close.
// TODO(vitaliyl): refactor.
bool is_framed_by_connection_close() const {
// We declare that response is framed by connection close if it has no
// content-length, no transfer encoding, and is allowed to have a body by
// the HTTP spec.
// parsed_response_code_ is 0 for requests, so ResponseCodeImpliesNoBody
// will return false.
return (content_length_status_ == BalsaHeadersEnums::NO_CONTENT_LENGTH) &&
!transfer_encoding_is_chunked_ &&
size_t content_length() const { return content_length_; }
BalsaHeadersEnums::ContentLengthStatus content_length_status() const {
return content_length_status_;
// SetContentLength and SetChunkEncoding modifies the header object to use
// content-length and transfer-encoding headers in a consistent manner. They
// set all internal flags and status so client can get a consistent view from
// various accessors.
void SetContentLength(size_t length);
void SetChunkEncoding(bool chunk_encode);
friend class BalsaFrame;
friend class SpdyFrame;
friend class HTTPMessage;
friend class BalsaHeadersTokenUtils;
const char* BeginningOfFirstLine() const {
return GetPtr(firstline_buffer_base_idx_);
char* GetPtr(BalsaBuffer::Blocks::size_type block_idx) {
return balsa_buffer_.GetPtr(block_idx);
const char* GetPtr(BalsaBuffer::Blocks::size_type block_idx) const {
return balsa_buffer_.GetPtr(block_idx);
void WriteFromFramer(const char* ptr, size_t size) {
balsa_buffer_.WriteToContiguousBuffer(base::StringPiece(ptr, size));
void DoneWritingFromFramer() {
const char* OriginalHeaderStreamBegin() const {
return balsa_buffer_.StartOfFirstBlock();
const char* OriginalHeaderStreamEnd() const {
return balsa_buffer_.EndOfFirstBlock();
size_t GetReadableBytesFromHeaderStream() const {
return OriginalHeaderStreamEnd() - OriginalHeaderStreamBegin();
void GetReadablePtrFromHeaderStream(const char** p, size_t* s) {
*p = OriginalHeaderStreamBegin();
*s = GetReadableBytesFromHeaderStream();
base::StringPiece GetValueFromHeaderLineDescription(
const HeaderLineDescription& line) const;
void AddAndMakeDescription(const base::StringPiece& key,
const base::StringPiece& value,
HeaderLineDescription* d);
void AppendOrPrependAndMakeDescription(const base::StringPiece& key,
const base::StringPiece& value,
bool append,
HeaderLineDescription* d);
// Removes all header lines with the given key starting at start.
void RemoveAllOfHeaderStartingAt(const base::StringPiece& key,
HeaderLines::iterator start);
// If the 'key' does not exist in the headers, calls
// AppendHeader(key, value). Otherwise if append is true, appends ',value'
// to the first existing header with key 'key'. If append is false, prepends
// 'value,' to the first existing header with key 'key'.
void AppendOrPrependToHeader(const base::StringPiece& key,
const base::StringPiece& value,
bool append);
HeaderLines::const_iterator GetConstHeaderLinesIterator(
const base::StringPiece& key,
HeaderLines::const_iterator start) const;
HeaderLines::iterator GetHeaderLinesIteratorNoSkip(
const base::StringPiece& key,
HeaderLines::iterator start);
HeaderLines::iterator GetHeaderLinesIterator(
const base::StringPiece& key,
HeaderLines::iterator start);
template <typename IteratorType>
const IteratorType HeaderLinesBeginHelper() const {
if (header_lines_.empty()) {
return IteratorType(this, 0);
const HeaderLines::size_type header_lines_size = header_lines_.size();
for (HeaderLines::size_type i = 0; i < header_lines_size; ++i) {
if (header_lines_[i].skip == false) {
return IteratorType(this, i);
return IteratorType(this, 0);
template <typename IteratorType>
const IteratorType HeaderLinesEndHelper() const {
if (header_lines_.empty()) {
return IteratorType(this, 0);
const HeaderLines::size_type header_lines_size = header_lines_.size();
HeaderLines::size_type i = header_lines_size;
do {
if (header_lines_[i].skip == false) {
return IteratorType(this, i + 1);
} while (i != 0);
return IteratorType(this, 0);
// At the moment, this function will always return the original headers.
// In the future, it may not do so after erasing header lines, modifying
// header lines, or modifying the first line.
// For this reason, it is strongly suggested that use of this function is
// only acceptable for the purpose of debugging parse errors seen by the
// BalsaFrame class.
base::StringPiece OriginalHeadersForDebugging() const {
return base::StringPiece(OriginalHeaderStreamBegin(),
OriginalHeaderStreamEnd() - OriginalHeaderStreamBegin());
BalsaBuffer balsa_buffer_;
size_t content_length_;
BalsaHeadersEnums::ContentLengthStatus content_length_status_;
size_t parsed_response_code_;
// HTTP firstlines all have the following structure:
// [\t \r\n]+ [^\t ]+ [\t ]+ [^\t ]+ [\t ]+ [^\t ]+ [^\r\n]+ "\r\n"
// ws1 nws1 ws2 nws2 ws3 nws3 ws4
// | [-------) [-------) [----------------)
// REQ: method request_uri version
// RESP: version statuscode reason
// The first NONWS->LWS component we'll call firstline_a.
// The second firstline_b, and the third firstline_c.
// firstline_a goes from nws1 to (but not including) ws2
// firstline_b goes from nws2 to (but not including) ws3
// firstline_c goes from nws3 to (but not including) ws4
// In the code:
// ws1 == whitespace_1_idx_
// nws1 == non_whitespace_1_idx_
// ws2 == whitespace_2_idx_
// nws2 == non_whitespace_2_idx_
// ws3 == whitespace_3_idx_
// nws3 == non_whitespace_3_idx_
// ws4 == whitespace_4_idx_
BalsaBuffer::Blocks::size_type firstline_buffer_base_idx_;
size_t whitespace_1_idx_;
size_t non_whitespace_1_idx_;
size_t whitespace_2_idx_;
size_t non_whitespace_2_idx_;
size_t whitespace_3_idx_;
size_t non_whitespace_3_idx_;
size_t whitespace_4_idx_;
size_t end_of_firstline_idx_;
bool transfer_encoding_is_chunked_;
HeaderLines header_lines_;
} // namespace net