Generate path names on the client side

src/gpu/gl/GrGLNameAllocator.h

+
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGLNameAllocator_DEFINED
+#define GrGLNameAllocator_DEFINED
+
+#include "SkRefCnt.h"
+#include "gl/GrGLFunctions.h"
+
+/**

[bsalomon, 2014/06/09 13:52:21]

Nice dox in this class, thanks!

+ * This class assumes ownership of an explicit range of OpenGL object names and
+ * manages allocations within that range. This allows the app to generate new
+ * objects on the client side without making round trips to the GL server.
+ */
+class GrGLNameAllocator {
+public:
+    /**
+     * Constructs a name allocator that produces names within the explicit
+     * half-open range [firstName, end). Note that the caller will most likely
+     * need to call glGen* beforehand to reserve a range within the GL driver,
+     * and then invoke this constructor with that range.
+     *
+     * @param firstName The first name in the range owned by this class. Must be
+                        greater than zero.
+     * @param endName   The first past-the-end name beyond the range owned by
+                        this class. Must be >= firstName.
+     */
+    GrGLNameAllocator(GrGLuint firstName, GrGLuint endName);
+
+    /**
+     * Destructs the name allocator. The caller is responsible for calling the
+     * appropriate glDelete* on the range if necessary.
+     */
+    ~GrGLNameAllocator();
+
+    /**
+     * Return the beginning of this class's range.
+     *
+     * @return The first name in the range owned by this class.
+     */
+    GrGLuint firstName() const { return fFirstName; }
+
+    /**
+     * Return the end of this class's range. Note that endName() is not owned by
+     * this class.
+     *
+     * @return One plus the final name in the range owned by this class.
+     */
+    GrGLuint endName() const { return fEndName; }
+
+    /**
+     * Allocate an OpenGL object name from within this class's range.
+     *
+     * @return The name if one was available,
+               0 if all the names in the range were already in use.
+     */
+    GrGLuint allocateName();
+
+    /**
+     * Free an OpenGL object name, allowing it to be returned by a future call
+     * to allocateName(). Note that the caller should most likely redefine the
+     * object as empty to deallocate any underlying GPU memory before calling
+     * this method (but not call glDelete*, since that would free up the name
+     * within the driver itself).
+     *
+     * @param name The object name to free. Not-allocated names are silently
+     *             ignored the same way they are in the OpenGL spec.
+     */
+    void free(GrGLuint name);
+
+private:
+    class SparseNameRange;
+    class SparseNameTree;
+    class ContiguousNameRange;
+
+    const GrGLuint fFirstName;
+    const GrGLuint fEndName;
+    SkAutoTUnref<SparseNameRange> fAllocatedNames;
+};
+
+#endif