src/core/SkTypefaceCache.h

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */



#ifndef SkTypefaceCache_DEFINED
#define SkTypefaceCache_DEFINED

#include "SkTypeface.h"
#include "SkTDArray.h"

/*  TODO
 *  Provide std way to cache name+requestedStyle aliases to the same typeface.
 *
 *  The current mechanism ends up create a diff typeface for each one, even if
 *  they map to the same internal obj (e.g. CTFontRef on the mac)
 */

class SkTypefaceCache {
public:
    typedef bool (*FindProc)(SkTypeface*, SkTypeface::Style, void* context);

    /**
     *  Helper: returns a unique fontID to pass to the constructor of
     *  your subclass of SkTypeface
     */
    static SkFontID NewFontID();

    /**
     *  Add a typeface to the cache. This ref()s the typeface, so that the
     *  cache is also an owner. Later, if we need to purge the cache, it will
     *  unref() typefaces whose refcnt is 1 (meaning only the cache is an owner).
     */
    static void Add(SkTypeface*, SkTypeface::Style requested);

    /**
     *  Search the cache for a typeface with the specified fontID (uniqueID).
     *  If one is found, return it (its reference count is unmodified). If none
     *  is found, return NULL.
     */
    static SkTypeface* FindByID(SkFontID fontID);

    /**
     *  Iterate through the cache, calling proc(typeface, ctx) with each
     *  typeface. If proc returns true, then we return that typeface (its
     *  reference count is unmodified). If it never returns true, we return NULL.
     */
    static SkTypeface* FindByProc(FindProc proc, void* ctx);

    /**
     *  Debugging only: dumps the status of the typefaces in the cache
     */
    static void Dump();

private:
    static SkTypefaceCache& Get();

    void add(SkTypeface*, SkTypeface::Style requested);
    SkTypeface* findByID(SkFontID findID) const;
    SkTypeface* findByProc(FindProc proc, void* ctx) const;
    void purge(int count);

    struct Rec {
        SkTypeface*         fFace;
        SkTypeface::Style   fRequestedStyle;
    };
    SkTDArray<Rec> fArray;
};

#endif