1 files changed, 158 insertions, 0 deletions
diff --git a/include/core/SkPixelRef.h b/include/core/SkPixelRef.h
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+++ b/include/core/SkPixelRef.h
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+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SkPixelRef_DEFINED
+#define SkPixelRef_DEFINED
+
+#include "SkRefCnt.h"
+#include "SkString.h"
+
+class SkColorTable;
+class SkMutex;
+class SkFlattenableReadBuffer;
+class SkFlattenableWriteBuffer;
+
+/** \class SkPixelRef
+
+    This class is the smart container for pixel memory, and is used with
+    SkBitmap. A pixelref is installed into a bitmap, and then the bitmap can
+    access the actual pixel memory by calling lockPixels/unlockPixels.
+
+    This class can be shared/accessed between multiple threads.
+*/
+class SkPixelRef : public SkRefCnt {
+public:
+    explicit SkPixelRef(SkMutex* mutex = NULL);
+    
+    /** Return the pixel memory returned from lockPixels, or null if the
+        lockCount is 0.
+    */
+    void* pixels() const { return fPixels; }
+
+    /** Return the current colorTable (if any) if pixels are locked, or null.
+    */
+    SkColorTable* colorTable() const { return fColorTable; }
+
+    /** Return the current lockcount (defaults to 0)
+    */
+    int getLockCount() const { return fLockCount; }
+
+    /** Call to access the pixel memory, which is returned. Balance with a call
+        to unlockPixels().
+    */
+    void lockPixels();
+    /** Call to balanace a previous call to lockPixels(). Returns the pixels
+        (or null) after the unlock. NOTE: lock calls can be nested, but the
+        matching number of unlock calls must be made in order to free the
+        memory (if the subclass implements caching/deferred-decoding.)
+    */
+    void unlockPixels();
+    
+    /** Returns a non-zero, unique value corresponding to the pixels in this
+        pixelref. Each time the pixels are changed (and notifyPixelsChanged is
+        called), a different generation ID will be returned.
+    */
+    uint32_t getGenerationID() const;
+    
+    /** Call this if you have changed the contents of the pixels. This will in-
+        turn cause a different generation ID value to be returned from
+        getGenerationID().
+    */
+    void notifyPixelsChanged();
+
+    /** Returns true if this pixelref is marked as immutable, meaning that the
+        contents of its pixels will not change for the lifetime of the pixelref.
+    */
+    bool isImmutable() const { return fIsImmutable; }
+    
+    /** Marks this pixelref is immutable, meaning that the contents of its
+        pixels will not change for the lifetime of the pixelref. This state can
+        be set on a pixelref, but it cannot be cleared once it is set.
+    */
+    void setImmutable();
+
+    /** Return the optional URI string associated with this pixelref. May be
+        null.
+    */
+    const char* getURI() const { return fURI.size() ? fURI.c_str() : NULL; }
+
+    /** Copy a URI string to this pixelref, or clear the URI if the uri is null
+     */
+    void setURI(const char uri[]) {
+        fURI.set(uri);
+    }
+    
+    /** Copy a URI string to this pixelref
+     */
+    void setURI(const char uri[], size_t len) {
+        fURI.set(uri, len);
+    }
+    
+    /** Assign a URI string to this pixelref.
+    */
+    void setURI(const SkString& uri) { fURI = uri; }
+
+    // serialization
+
+    typedef SkPixelRef* (*Factory)(SkFlattenableReadBuffer&);
+
+    virtual Factory getFactory() const { return NULL; }
+    virtual void flatten(SkFlattenableWriteBuffer&) const;
+
+    static Factory NameToFactory(const char name[]);
+    static const char* FactoryToName(Factory);
+    static void Register(const char name[], Factory);
+    
+    class Registrar {
+    public:
+        Registrar(const char name[], Factory factory) {
+            SkPixelRef::Register(name, factory);
+        }
+    };
+
+protected:
+    /** Called when the lockCount goes from 0 to 1. The caller will have already
+        acquire a mutex for thread safety, so this method need not do that.
+    */
+    virtual void* onLockPixels(SkColorTable**) = 0;
+    /** Called when the lock count goes from 1 to 0. The caller will have
+        already acquire a mutex for thread safety, so this method need not do
+        that.
+    */
+    virtual void onUnlockPixels() = 0;
+
+    /** Return the mutex associated with this pixelref. This value is assigned
+        in the constructor, and cannot change during the lifetime of the object.
+    */
+    SkMutex* mutex() const { return fMutex; }
+
+    SkPixelRef(SkFlattenableReadBuffer&, SkMutex*);
+
+private:
+    SkMutex*        fMutex; // must remain in scope for the life of this object
+    void*           fPixels;
+    SkColorTable*   fColorTable;    // we do not track ownership, subclass does
+    int             fLockCount;
+    
+    mutable uint32_t fGenerationID;
+    
+    SkString    fURI;
+
+    // can go from false to true, but never from true to false
+    bool    fIsImmutable;
+};
+
+#endif