command_buffer: Implement path rendering functions for CHROMIUM_path_rendering

gpu/command_buffer/service/path_manager.h

Index: gpu/command_buffer/service/path_manager.h
diff --git a/gpu/command_buffer/service/path_manager.h b/gpu/command_buffer/service/path_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..78a53b7e203f463ce45da0f46afcdd786cc24207
--- /dev/null
+++ b/gpu/command_buffer/service/path_manager.h
@@ -0,0 +1,68 @@
+// Copyright (c) 2015 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 GPU_COMMAND_BUFFER_SERVICE_PATH_MANAGER_H_
+#define GPU_COMMAND_BUFFER_SERVICE_PATH_MANAGER_H_
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "gpu/command_buffer/service/gl_utils.h"
+#include "gpu/gpu_export.h"
+
+namespace gpu {
+namespace gles2 {
+
+// This class keeps track of paths and their client and service ids
+// so we can correctly clear them.
+class GPU_EXPORT PathManager {
+ public:
+  PathManager();
+  ~PathManager();
+
+  // Must call before destruction.
+  void Destroy(bool have_context);
+
+  // Creates a path mapping between closed intervals
+  // [first_client_id, last_client_id] -> [first_service_id, ...].
+  void CreatePathRange(GLuint first_client_id,
+                       GLuint last_client_id,
+                       GLuint first_service_id);
+
+  // Returns true if any path exists in the closed interval
+  // [first_client_id, last_client_id].
+  bool HasPathsInRange(GLuint first_client_id, GLuint last_client_id) const;
+
+  // Gets the path id corresponding the client path id.
+  // Returns false if no such service path id was not found.
+  bool GetPath(GLuint client_id, GLuint* service_id) const;
+
+  // Removes a closed interval of paths [first_client_id, last_client_id].
+  void RemovePaths(GLuint first_client_id, GLuint last_client_id);
+
+  // Mapping between client id and service id.
+  // Should be used only by the implementation.
+  struct PathRangeDescription {
+    PathRangeDescription(GLuint last_client, GLuint first_service)
+        : last_client_id(last_client), first_service_id(first_service) {}
+    GLuint last_client_id;
+    GLuint first_service_id;
+    typedef GLuint ServiceIdType;
+  };
+  typedef std::map<GLuint, PathRangeDescription> PathRangeMap;
+
+ private:
+  // Checks for consistency inside the book-keeping structures. Used as
+  // DCHECK pre/post condition in mutating functions.
+  bool CheckConsistency();
+
+  PathRangeMap path_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(PathManager);
+};
+
+}  // namespace gles2
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_SERVICE_PATH_MANAGER_H_