Landing the open source version of the FLIP server.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/463009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@33766 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 1306 insertions, 0 deletions

diff --git a/net/tools/flip_server/balsa_headers.h b/net/tools/flip_server/balsa_headers.h
new file mode 100644
index 0000000..8685ac5
--- /dev/null
+++ b/net/tools/flip_server/balsa_headers.h
@@ -0,0 +1,1306 @@
+// Copyright (c) 2009 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.
+
+#ifndef NET_TOOLS_FLIP_SERVER_BALSA_HEADERS_H_
+#define NET_TOOLS_FLIP_SERVER_BALSA_HEADERS_H_
+
+#include <iostream>
+#include <iterator>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/port.h"
+#include "net/tools/flip_server/balsa_enums.h"
+#ifdef CHROMIUM
+#include "base/string_piece.h"
+
+void SplitStringPieceToVector(StringPiece, char*, vector<StringPiece>*, bool) {
+  ...
+}
+
+struct StringPieceCaseHash {
+  size_t operator()(const StringPiece& sp) const {
+    // based on __stl_string_hash in http://www.sgi.com/tech/stl/string
+    unsigned long hash_val = 0;
+    for (StringPiece::const_iterator it = sp.begin();
+         it != sp.end(); ++it) {
+      hash_val = 5 * hash_val + ascii_tolower(*it);
+    }
+    return static_cast<size_t>(hash_val);
+  }
+};
+
+struct StringPieceCaseEqual {
+  bool operator()(const StringPiece& piece1, const StringPiece& piece2) const {
+    return StringPieceUtils::EqualIgnoreCase(piece1, piece2);
+  }
+};
+
+#else
+#include "strings/stringpiece.h"
+#include "strings/stringpiece_utils.h"
+#endif
+
+namespace gfe2 {
+
+// WARNING:
+// 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 {
+ public:
+  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;
+
+  // 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 {
+   public:
+    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 vector<BufferBlock> Blocks;
+
+  ~BalsaBuffer() {
+    CleanupBlocksStartingFrom(0);
+  }
+
+  // Returns the total amount of memory used by the buffer blocks.
+  size_t GetTotalBufferBlockSize() const {
+    size_t buffer_size = 0;
+    for (Blocks::const_iterator iter = blocks_.begin();
+         iter != blocks_.end();
+         ++iter) {
+      buffer_size += iter->buffer_size;
+    }
+    return buffer_size;
+  }
+
+  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 StringPiece& sp) {
+    if (sp.empty()) {
+      return;
+    }
+    CHECK(can_write_to_contiguous_buffer_);
+    DCHECK_GE(blocks_.size(), 1);
+    if (blocks_[0].buffer == NULL && sp.size() <= blocksize_) {
+      blocks_[0] = AllocBlock();
+      memcpy(blocks_[0].start_of_unused_bytes(), sp.data(), sp.size());
+    } else if (blocks_[0].bytes_free < sp.size()) {
+      // the first block isn't big enough, resize it.
+      const size_t old_storage_size_used = blocks_[0].bytes_used();
+      const size_t new_storage_size = old_storage_size_used + sp.size();
+      char* new_storage = new char[new_storage_size];
+      char* old_storage = blocks_[0].buffer;
+      if (old_storage_size_used) {
+        memcpy(new_storage, old_storage, old_storage_size_used);
+      }
+      memcpy(new_storage + old_storage_size_used, sp.data(), sp.size());
+      blocks_[0].buffer = new_storage;
+      blocks_[0].bytes_free = sp.size();
+      blocks_[0].buffer_size = new_storage_size;
+      delete[] old_storage;
+    } else {
+      memcpy(blocks_[0].start_of_unused_bytes(), sp.data(), sp.size());
+    }
+    blocks_[0].bytes_free -= sp.size();
+  }
+
+  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.
+  StringPiece Write(const StringPiece& sp,
+                    Blocks::size_type* block_buffer_idx) {
+    if (sp.empty()) {
+      return sp;
+    }
+    char* storage = Reserve(sp.size(), block_buffer_idx);
+    memcpy(storage, sp.data(), sp.size());
+    return StringPiece(storage, sp.size());
+  }
+
+  // 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) {
+    // There should always be a 'first_block', even if it
+    // contains nothing.
+    DCHECK_GE(blocks_.size(), 1);
+    BufferBlock* block = NULL;
+    Blocks::size_type block_idx = can_write_to_contiguous_buffer_ ? 1 : 0;
+    for (; block_idx < blocks_.size(); ++block_idx) {
+      if (blocks_[block_idx].bytes_free >= size) {
+        block = &blocks_[block_idx];
+        break;
+      }
+    }
+    if (block == NULL) {
+      if (blocksize_ < size) {
+        blocks_.push_back(AllocCustomBlock(size));
+      } else {
+        blocks_.push_back(AllocBlock());
+      }
+      block = &blocks_.back();
+    }
+
+    char* storage = block->start_of_unused_bytes();
+    block->bytes_free -= size;
+    if (block_buffer_idx) {
+      *block_buffer_idx = block_idx;
+    }
+    return storage;
+  }
+
+  void Clear() {
+    CHECK(!blocks_.empty());
+    if (blocksize_ == blocks_[0].buffer_size) {
+      CleanupBlocksStartingFrom(1);
+      blocks_[0].bytes_free = blocks_[0].buffer_size;
+    } else {
+      CleanupBlocksStartingFrom(0);
+      blocks_.push_back(AllocBlock());
+    }
+    DCHECK_GE(blocks_.size(), 1);
+    can_write_to_contiguous_buffer_ = true;
+  }
+
+  void Swap(BalsaBuffer* b) {
+    blocks_.swap(b->blocks_);
+    swap(can_write_to_contiguous_buffer_, b->can_write_to_contiguous_buffer_);
+    swap(blocksize_, b->blocksize_);
+  }
+
+  void CopyFrom(const BalsaBuffer& b) {
+    CleanupBlocksStartingFrom(0);
+    blocks_.resize(b.blocks_.size());
+    for (Blocks::size_type i = 0; i < blocks_.size(); ++i) {
+      blocks_[i] = CopyBlock(b.blocks_[i]);
+    }
+    blocksize_ = b.blocksize_;
+    can_write_to_contiguous_buffer_ = b.can_write_to_contiguous_buffer_;
+  }
+
+  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(); }
+
+ protected:
+  BalsaBuffer() :
+      blocksize_(kDefaultBlocksize), can_write_to_contiguous_buffer_(true) {
+    blocks_.push_back(AllocBlock());
+  }
+
+  explicit BalsaBuffer(size_t blocksize) :
+      blocksize_(blocksize), can_write_to_contiguous_buffer_(true) {
+    blocks_.push_back(AllocBlock());
+  }
+
+  BufferBlock AllocBlock() {
+    return AllocCustomBlock(blocksize_);
+  }
+
+  BufferBlock AllocCustomBlock(size_t blocksize) {
+    return BufferBlock(new char[blocksize], blocksize, blocksize);
+  }
+
+  BufferBlock CopyBlock(const BufferBlock& b) {
+    BufferBlock block = b;
+    if (b.buffer == NULL) {
+      return block;
+    }
+
+    block.buffer = new char[b.buffer_size];
+    memcpy(block.buffer, b.buffer, b.bytes_used());
+    return block;
+  }
+
+  // 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) {
+    for (Blocks::size_type i = start_idx; i < blocks_.size(); ++i) {
+      delete[] blocks_[i].buffer;
+    }
+    blocks_.resize(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 {
+ public:
+  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) :
+        first_char_idx(first_character_index),
+        key_end_idx(key_end_index),
+        value_begin_idx(value_begin_index),
+        last_char_idx(last_character_index),
+        buffer_base_idx(buffer_base_index),
+        skip(false) {}
+
+    HeaderLineDescription() :
+        first_char_idx(0),
+        key_end_idx(0),
+        value_begin_idx(0),
+        last_char_idx(0),
+        buffer_base_idx(0),
+        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 vector<StringPiece> HeaderTokenList;
+  friend bool gfe2::ParseHTTPFirstLine(const char* begin,
+                                       const char* end,
+                                       bool is_request,
+                                       size_t max_request_uri_length,
+                                       BalsaHeaders* headers,
+                                       BalsaFrameEnums::ErrorCode* error_code);
+
+ protected:
+  typedef 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 {
+   public:
+    friend class BalsaHeaders;
+    friend class reverse_iterator_base;
+    typedef pair<StringPiece, 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.
+    iterator_base() : headers_(NULL), idx_(0) { }
+
+    // copy constructor.
+    iterator_base(const iterator_base& it)
+      : headers_(it.headers_),
+        idx_(it.idx_) {}
+
+    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.
+    friend ostream& operator<<(ostream& os, const iterator_base& it) {
+      os << "[" << it.headers_ << ", " << it.idx_ << "]";
+      return os;
+    }
+
+   protected:
+    iterator_base(const BalsaHeaders* headers, HeaderLines::size_type index) :
+        headers_(headers),
+        idx_(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 {
+        ++idx_;
+      } 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 {
+        --idx_;
+      } while (idx_ >= 0 &&
+              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_ < 0 || 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(
+          StringPiece(stream_begin + line.first_char_idx,
+                      line.key_end_idx - line.first_char_idx),
+          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 {
+   public:
+    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) { }
+
+   protected:
+    void increment() {
+      --idx_;
+      iterator_base::decrement();
+      ++idx_;
+    }
+
+    void decrement() {
+      ++idx_;
+      iterator_base::increment();
+      --idx_;
+    }
+
+    reverse_iterator_base(const BalsaHeaders* headers,
+                          HeaderLines::size_type index) :
+        iterator_base(headers, index) {}
+  };
+
+ public:
+  class const_header_lines_iterator : public iterator_base {
+    friend class BalsaHeaders;
+   public:
+    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++() {
+      iterator_base::increment();
+      return *this;
+    }
+
+    self& operator--() {
+      iterator_base::decrement();
+      return *this;
+    }
+   protected:
+    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 {
+   public:
+    typedef const_reverse_header_lines_iterator self;
+    const_reverse_header_lines_iterator() : reverse_iterator_base() {}
+
+    const_reverse_header_lines_iterator(
+      const const_header_lines_iterator& it) :
+        reverse_iterator_base(it.headers_, it.idx_) {}
+
+    const_reverse_header_lines_iterator(
+      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++() {
+      reverse_iterator_base::increment();
+      return *this;
+    }
+
+    self& operator--() {
+      reverse_iterator_base::decrement();
+      return *this;
+    }
+   protected:
+    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;
+   public:
+    typedef const_header_lines_key_iterator self;
+
+    self& operator++() {
+      do {
+        iterator_base::increment();
+      } while (!AtEnd() &&
+               !StringPieceUtils::EqualIgnoreCase(key_, (**this).first));
+      return *this;
+    }
+
+    void operator++(int ignore) {
+      ++(*this);
+    }
+
+    // Only forward-iteration makes sense, so no operator-- defined.
+
+   private:
+    const_header_lines_key_iterator(const BalsaHeaders* headers,
+                                    HeaderLines::size_type index,
+                                    const StringPiece& key)
+        : iterator_base(headers, index),
+          key_(key) {
+    }
+
+    // Should only be used for creating an end iterator.
+    const_header_lines_key_iterator(const BalsaHeaders* headers,
+                                    HeaderLines::size_type index)
+        : iterator_base(headers, index) {
+    }
+
+    bool AtEnd() const {
+      return *this >= headers_->header_lines_end();
+    }
+
+    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.)
+  BalsaHeaders() :
+      balsa_buffer_(4096),
+      content_length_(0),
+      content_length_status_(BalsaHeadersEnums::NO_CONTENT_LENGTH),
+      parsed_response_code_(0),
+      firstline_buffer_base_idx_(0),
+      whitespace_1_idx_(0),
+      non_whitespace_1_idx_(0),
+      whitespace_2_idx_(0),
+      non_whitespace_2_idx_(0),
+      whitespace_3_idx_(0),
+      non_whitespace_3_idx_(0),
+      whitespace_4_idx_(0),
+      end_of_firstline_idx_(0),
+      transfer_encoding_is_chunked_(false) { }
+
+  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_, 0);
+    header_lines_[it.idx_].skip = true;
+  }
+
+  void Clear();
+
+  void Swap(BalsaHeaders* other);
+
+  void CopyFrom(const BalsaHeaders& other);
+
+  // Exists until it is allowable to turn on header-order
+  // computation in the X-Google-GFE-Frontline-Info header, instead
+  // of requiring GFEv2 to output in the same header order in
+  // which it has received data.
+  // TODO(fenix): remove this function and rename all occurances
+  // of it in the code to AppendHeader when the condition above
+  // has been satisified.
+  void HackHeader(const StringPiece& key, const 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 StringPiece& key, const 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 StringPiece& key, const 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 StringPiece& key, const 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 StringPiece& key, const 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 StringPiece& key, const StringPiece& value);
+
+  const StringPiece GetHeader(const 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 StringPiece& key, vector<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 StringPiece& key, string* out) const;
+
+  // Returns true if RFC 2616 Section 14 indicates that header can
+  // have multiple values.
+  static bool IsMultivaluedHeader(const StringPiece& header);
+
+  // Determine if a given header is present.
+  inline bool HasHeader(const StringPiece& key) const {
+    return (GetConstHeaderLinesIterator(key, header_lines_.begin()) !=
+            header_lines_.end());
+  }
+
+  // Returns true iff any header 'key' exists with non-empty value.
+  bool HasNonEmptyHeader(const StringPiece& key) const;
+
+  const_header_lines_iterator GetHeaderPosition(const 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 StringPiece& key) const;
+
+  void RemoveAllOfHeader(const StringPiece& key);
+
+  // Removes all headers starting with 'key' [case insensitive]
+  void RemoveAllHeadersWithPrefix(const 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 {
+    WriteToBuffer(buffer);
+    WriteHeaderEndingToBuffer(buffer);
+  }
+
+  // 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) {
+        continue;
+      }
+      const char* line_ptr = GetPtr(line.buffer_base_idx);
+      WriteHeaderLineToBuffer(
+          buffer,
+          StringPiece(line_ptr + line.first_char_idx,
+                      line.key_end_idx - line.first_char_idx),
+          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 StringPiece& key,
+                                      const 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.size() > 0) {
+      buffer->Write(key.data(), key.size());
+      buffer->Write(": ", 2);
+      buffer->Write(value.data(), 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. 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.
+  // The header content is appended to the string; the original content is not
+  // cleared.
+  void DumpToString(string* str) const;
+
+  const StringPiece first_line() const {
+    DCHECK_GE(whitespace_4_idx_, non_whitespace_1_idx_);
+    return 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 StringPiece request_method() const {
+    DCHECK_GE(whitespace_2_idx_, non_whitespace_1_idx_);
+    return StringPiece(BeginningOfFirstLine() + non_whitespace_1_idx_,
+                       whitespace_2_idx_ - non_whitespace_1_idx_);
+  }
+
+  const 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 StringPiece request_uri() const {
+    DCHECK_GE(whitespace_3_idx_, non_whitespace_2_idx_);
+    return StringPiece(BeginningOfFirstLine() + non_whitespace_2_idx_,
+                       whitespace_3_idx_ - non_whitespace_2_idx_);
+  }
+
+  const 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 StringPiece request_version() const {
+    DCHECK_GE(whitespace_4_idx_, non_whitespace_3_idx_);
+    return StringPiece(BeginningOfFirstLine() + non_whitespace_3_idx_,
+                       whitespace_4_idx_ - non_whitespace_3_idx_);
+  }
+
+  const 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 StringPiece& firstline_a,
+                                    const StringPiece& firstline_b,
+                                    const StringPiece& firstline_c);
+
+  void SetRequestFirstlineFromStringPieces(const StringPiece& method,
+                                           const StringPiece& uri,
+                                           const StringPiece& version) {
+    SetFirstlineFromStringPieces(method, uri, version);
+  }
+
+  void SetResponseFirstlineFromStringPieces(const StringPiece& version,
+                                            const StringPiece& code,
+                                            const 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 StringPiece& method);
+  void SetResponseVersion(const StringPiece& version);
+
+  void SetRequestUri(const StringPiece& uri);
+  void SetResponseCode(const 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 StringPiece& version);
+  void SetResponseReasonPhrase(const 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 StringPiece& line);
+
+  // Simple accessors to some of the internal state
+  bool transfer_encoding_is_chunked() const {
+    return transfer_encoding_is_chunked_;
+  }
+
+  static bool ResponseCodeImpliesNoBody(int 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_ &&
+        !ResponseCodeImpliesNoBody(parsed_response_code_);
+  }
+
+  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);
+
+ protected:
+  friend class BalsaFrame;
+  friend class FlipFrame;
+  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(StringPiece(ptr, size));
+  }
+
+  void DoneWritingFromFramer() {
+    balsa_buffer_.NoMoreWriteToContiguousBuffer();
+  }
+
+  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();
+  }
+
+  StringPiece GetValueFromHeaderLineDescription(
+      const HeaderLineDescription& line) const;
+
+  void AddAndMakeDescription(const StringPiece& key,
+                             const StringPiece& value,
+                             HeaderLineDescription* d);
+
+  void AppendOrPrependAndMakeDescription(const StringPiece& key,
+                                         const StringPiece& value,
+                                         bool append,
+                                         HeaderLineDescription* d);
+
+  // Removes all header lines with the given key starting at start.
+  void RemoveAllOfHeaderStartingAt(const 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 StringPiece& key,
+                               const StringPiece& value,
+                               bool append);
+
+  HeaderLines::const_iterator GetConstHeaderLinesIterator(
+      const StringPiece& key,
+      HeaderLines::const_iterator start) const;
+
+  HeaderLines::iterator GetHeaderLinesIteratorNoSkip(
+      const StringPiece& key,
+      HeaderLines::iterator start);
+
+  HeaderLines::iterator GetHeaderLinesIterator(
+      const 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 {
+      --i;
+      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.
+  StringPiece OriginalHeadersForDebugging() const {
+    return 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:
+  //  LWS         NONWS  LWS    NONWS   LWS    NONWS   NOTCRLF  CRLF
+  //  [\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 gfe2
+
+#endif  // NET_TOOLS_FLIP_SERVER_BALSA_HEADERS_H_
+