include/graphics/SkGlobals.h

/* include/graphics/SkGlobals.h
**
** Copyright 2006, Google Inc.
**
** 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 SkGlobals_DEFINED
#define SkGlobals_DEFINED

#include "SkThread.h"

class SkGlobals {
public:
    class Rec {
    public:
        virtual ~Rec();
    private:
        Rec*    fNext;
        U32     fTag;

        friend class SkGlobals;
    };

    /** Look for a matching Rec for the specified tag. If one is found, return it.
        If one is not found, if create_proc is nil, return nil, else
        call the proc, and if it returns a Rec, add it to the global list
        and return it.

        create_proc can NOT call back into SkGlobals::Find (it would deadlock)
    */
    static Rec* Find(U32 tag, Rec* (*create_proc)());
    /** Helper for Find, when you want to assert that the Rec is already in the list
    */
    static Rec* Get(U32 tag)
    {
        Rec* rec = SkGlobals::Find(tag, nil);
        SkASSERT(rec);
        return rec;
    }

    // used by porting layer
    struct BootStrap {
        SkMutex fMutex;
        Rec*    fHead;
    };

private:
    static void Init();
    static void Term();
    friend class SkGraphics;

    //  This last function is implemented in the porting layer
    static BootStrap& GetBootStrap();
};

#endif