Adds a hy-phen-ator.

content/renderer/hyphenator/hyphenator.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 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"
+
+namespace file_util {
+class MemoryMappedFile;
+}
+
+typedef struct _HyphenDict HyphenDict;
+
+namespace content {
+
+// 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:
+  explicit Hyphenator(base::PlatformFile file);
+  ~Hyphenator();
+
+  // Initializes the hyphen library and allocates resources needed for
+  // hyphenation.
+  bool Initialize();
+
+  // 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);
+
+ private:
+  // 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.)
+  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_