Split net/spdy into core and chromium subdirectories.

net/spdy/spdy_header_block.h

-// Copyright (c) 2012 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_SPDY_SPDY_HEADER_BLOCK_H_
-#define NET_SPDY_SPDY_HEADER_BLOCK_H_
-
-#include <stddef.h>
-
-#include <list>
-#include <map>
-#include <memory>
-#include <utility>
-#include <vector>
-
-#include "base/macros.h"
-#include "net/base/linked_hash_map.h"
-#include "net/base/net_export.h"
-#include "net/log/net_log.h"
-#include "net/spdy/platform/api/spdy_string.h"
-#include "net/spdy/platform/api/spdy_string_piece.h"
-
-namespace base {
-class Value;
-}
-
-namespace net {
-
-class NetLogCaptureMode;
-
-namespace test {
-class SpdyHeaderBlockPeer;
-class ValueProxyPeer;
-}
-
-// This class provides a key-value map that can be used to store SPDY header
-// names and values. This data structure preserves insertion order.
-//
-// Under the hood, this data structure uses large, contiguous blocks of memory
-// to store names and values. Lookups may be performed with SpdyStringPiece
-// keys, and values are returned as SpdyStringPieces (via ValueProxy, below).
-// Value SpdyStringPieces are valid as long as the SpdyHeaderBlock exists;
-// allocated memory is never freed until SpdyHeaderBlock's destruction.
-//
-// This implementation does not make much of an effort to minimize wasted space.
-// It's expected that keys are rarely deleted from a SpdyHeaderBlock.
-class NET_EXPORT SpdyHeaderBlock {
- private:
-  class Storage;
-
-  // Stores a list of value fragments that can be joined later with a
-  // key-dependent separator.
-  class NET_EXPORT HeaderValue {
-   public:
-    HeaderValue(Storage* storage,
-                SpdyStringPiece key,
-                SpdyStringPiece initial_value);
-
-    // Moves are allowed.
-    HeaderValue(HeaderValue&& other);
-    HeaderValue& operator=(HeaderValue&& other);
-
-    // Copies are not.
-    HeaderValue(const HeaderValue& other) = delete;
-    HeaderValue& operator=(const HeaderValue& other) = delete;
-
-    ~HeaderValue();
-
-    // Consumes at most |fragment.size()| bytes of memory.
-    void Append(SpdyStringPiece fragment);
-
-    SpdyStringPiece value() const { return as_pair().second; }
-    const std::pair<SpdyStringPiece, SpdyStringPiece>& as_pair() const;
-
-   private:
-    // May allocate a large contiguous region of memory to hold the concatenated
-    // fragments and separators.
-    SpdyStringPiece ConsolidatedValue() const;
-
-    mutable Storage* storage_;
-    mutable std::vector<SpdyStringPiece> fragments_;
-    // The first element is the key; the second is the consolidated value.
-    mutable std::pair<SpdyStringPiece, SpdyStringPiece> pair_;
-  };
-
-  typedef linked_hash_map<SpdyStringPiece, HeaderValue, base::StringPieceHash>
-      MapType;
-
- public:
-  typedef std::pair<SpdyStringPiece, SpdyStringPiece> value_type;
-
-  // Provides iteration over a sequence of std::pair<SpdyStringPiece,
-  // SpdyStringPiece>, even though the underlying MapType::value_type is
-  // different. Dereferencing the iterator will result in memory allocation for
-  // multi-value headers.
-  class NET_EXPORT iterator {
-   public:
-    // The following type definitions fulfill the requirements for iterator
-    // implementations.
-    typedef std::pair<SpdyStringPiece, SpdyStringPiece> value_type;
-    typedef value_type& reference;
-    typedef value_type* pointer;
-    typedef std::forward_iterator_tag iterator_category;
-    typedef MapType::iterator::difference_type difference_type;
-
-    // In practice, this iterator only offers access to const value_type.
-    typedef const value_type& const_reference;
-    typedef const value_type* const_pointer;
-
-    explicit iterator(MapType::const_iterator it);
-    iterator(const iterator& other);
-    ~iterator();
-
-    // This will result in memory allocation if the value consists of multiple
-    // fragments.
-    const_reference operator*() const { return it_->second.as_pair(); }
-
-    const_pointer operator->() const { return &(this->operator*()); }
-    bool operator==(const iterator& it) const { return it_ == it.it_; }
-    bool operator!=(const iterator& it) const { return !(*this == it); }
-
-    iterator& operator++() {
-      it_++;
-      return *this;
-    }
-
-    iterator operator++(int) {
-      auto ret = *this;
-      this->operator++();
-      return ret;
-    }
-
-   private:
-    MapType::const_iterator it_;
-  };
-  typedef iterator const_iterator;
-
-  class ValueProxy;
-
-  SpdyHeaderBlock();
-  SpdyHeaderBlock(const SpdyHeaderBlock& other) = delete;
-  SpdyHeaderBlock(SpdyHeaderBlock&& other);
-  ~SpdyHeaderBlock();
-
-  SpdyHeaderBlock& operator=(const SpdyHeaderBlock& other) = delete;
-  SpdyHeaderBlock& operator=(SpdyHeaderBlock&& other);
-  SpdyHeaderBlock Clone() const;
-
-  bool operator==(const SpdyHeaderBlock& other) const;
-  bool operator!=(const SpdyHeaderBlock& other) const;
-
-  // Provides a human readable multi-line representation of the stored header
-  // keys and values.
-  SpdyString DebugString() const;
-
-  iterator begin() { return iterator(block_.begin()); }
-  iterator end() { return iterator(block_.end()); }
-  const_iterator begin() const { return const_iterator(block_.begin()); }
-  const_iterator end() const { return const_iterator(block_.end()); }
-  bool empty() const { return block_.empty(); }
-  size_t size() const { return block_.size(); }
-  iterator find(SpdyStringPiece key) { return iterator(block_.find(key)); }
-  const_iterator find(SpdyStringPiece key) const {
-    return const_iterator(block_.find(key));
-  }
-  void erase(SpdyStringPiece key) { block_.erase(key); }
-
-  // Clears both our MapType member and the memory used to hold headers.
-  void clear();
-
-  // The next few methods copy data into our backing storage.
-
-  // If key already exists in the block, replaces the value of that key. Else
-  // adds a new header to the end of the block.
-  void insert(const value_type& value);
-
-  // If a header with the key is already present, then append the value to the
-  // existing header value, NUL ("\0") separated unless the key is cookie, in
-  // which case the separator is "; ".
-  // If there is no such key, a new header with the key and value is added.
-  void AppendValueOrAddHeader(const SpdyStringPiece key,
-                              const SpdyStringPiece value);
-
-  // Allows either lookup or mutation of the value associated with a key.
-  ValueProxy operator[](const SpdyStringPiece key);
-
-  // This object provides automatic conversions that allow SpdyHeaderBlock to be
-  // nearly a drop-in replacement for linked_hash_map<SpdyString, SpdyString>.
-  // It reads data from or writes data to a SpdyHeaderBlock::Storage.
-  class NET_EXPORT ValueProxy {
-   public:
-    ~ValueProxy();
-
-    // Moves are allowed.
-    ValueProxy(ValueProxy&& other);
-    ValueProxy& operator=(ValueProxy&& other);
-
-    // Copies are not.
-    ValueProxy(const ValueProxy& other) = delete;
-    ValueProxy& operator=(const ValueProxy& other) = delete;
-
-    // Assignment modifies the underlying SpdyHeaderBlock.
-    ValueProxy& operator=(const SpdyStringPiece other);
-
-    SpdyString as_string() const;
-
-   private:
-    friend class SpdyHeaderBlock;
-    friend class test::ValueProxyPeer;
-
-    ValueProxy(SpdyHeaderBlock::MapType* block,
-               SpdyHeaderBlock::Storage* storage,
-               SpdyHeaderBlock::MapType::iterator lookup_result,
-               const SpdyStringPiece key);
-
-    SpdyHeaderBlock::MapType* block_;
-    SpdyHeaderBlock::Storage* storage_;
-    SpdyHeaderBlock::MapType::iterator lookup_result_;
-    SpdyStringPiece key_;
-    bool valid_;
-  };
-
-  // Returns the estimate of dynamically allocated memory in bytes.
-  size_t EstimateMemoryUsage() const;
-
- private:
-  friend class test::SpdyHeaderBlockPeer;
-
-  void AppendHeader(const SpdyStringPiece key, const SpdyStringPiece value);
-  Storage* GetStorage();
-  size_t bytes_allocated() const;
-
-  // SpdyStringPieces held by |block_| point to memory owned by |*storage_|.
-  // |storage_| might be nullptr as long as |block_| is empty.
-  MapType block_;
-  std::unique_ptr<Storage> storage_;
-};
-
-// Writes |fragments| to |dst|, joined by |separator|. |dst| must be large
-// enough to hold the result. Returns the number of bytes written.
-NET_EXPORT size_t Join(char* dst,
-                       const std::vector<SpdyStringPiece>& fragments,
-                       SpdyStringPiece separator);
-
-// Converts a SpdyHeaderBlock into NetLog event parameters.
-NET_EXPORT std::unique_ptr<base::Value> SpdyHeaderBlockNetLogCallback(
-    const SpdyHeaderBlock* headers,
-    NetLogCaptureMode capture_mode);
-
-// Converts NetLog event parameters into a SPDY header block and writes them
-// to |headers|.  |event_param| must have been created by
-// SpdyHeaderBlockNetLogCallback.  On failure, returns false and clears
-// |headers|.
-NET_EXPORT bool SpdyHeaderBlockFromNetLogParam(
-    const base::Value* event_param,
-    SpdyHeaderBlock* headers);
-
-}  // namespace net
-
-#endif  // NET_SPDY_SPDY_HEADER_BLOCK_H_