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// 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 CONTENT_RENDERER_HYPHENATOR_HYPHENATOR_H_
#define CONTENT_RENDERER_HYPHENATOR_HYPHENATOR_H_
#include <vector>
#include "base/memory/scoped_ptr.h"
#include "base/platform_file.h"
#include "base/string16.h"
#include "content/common/content_export.h"
#include "content/public/renderer/render_process_observer.h"
#include "ipc/ipc_platform_file.h"
namespace file_util {
class MemoryMappedFile;
}
typedef struct _HyphenDict HyphenDict;
namespace content {
class RenderThread;
// A class that hyphenates a word. This class encapsulates the hyphen library
// and manages resources used by the library. When this class uses a huge
// dictionary, it takes lots of memory (~1.3MB for English). A renderer should
// create this object only when it renders a page that needs hyphenation and
// deletes it when it moves to a page that does not need hyphenation.
class CONTENT_EXPORT Hyphenator : public RenderProcessObserver {
public:
explicit Hyphenator(base::PlatformFile file);
virtual ~Hyphenator();
// Initializes the hyphen library and allocates resources needed for
// hyphenation.
bool Initialize();
bool Attach(RenderThread* thread, const string16& locale);
// Returns whether this object can hyphenate words. When this object does not
// have a dictionary file attached, this function sends an IPC request to open
// the file.
bool CanHyphenate(const string16& locale);
// Returns the last hyphenation point, the position where we can insert a
// hyphen, before the given position. If there are not any hyphenation points,
// this function returns 0.
size_t ComputeLastHyphenLocation(const string16& word, size_t before_index);
// RenderProcessObserver implementation.
virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
private:
void OnSetDictionary(IPC::PlatformFileForTransit rule_file);
// The dictionary used by the hyphen library.
HyphenDict* dictionary_;
// The dictionary file and its memory-mapping object. (Our copy of the hyphen
// library uses a memory-mapped file opened by a browser so renderers can use
// it without opening the file.)
string16 locale_;
base::PlatformFile rule_file_;
scoped_ptr<file_util::MemoryMappedFile> rule_map_;
// A cached result. WebKit often calls ComputeLastHyphenLocation with the same
// word multiple times to find the best hyphenation point when it finds a line
// break. On the other hand, the hyphen library returns all hyphenation points
// for a word. This class caches the hyphenation points returned by the hyphen
// library to avoid calling the library multiple times.
string16 word_;
bool result_;
std::vector<int> hyphen_offsets_;
DISALLOW_COPY_AND_ASSIGN(Hyphenator);
};
} // namespace content
#endif // CONTENT_RENDERER_HYPHENATOR_HYPHENATOR_H_
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