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Port SkLazyFnPtr users to SkOncePtr.

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First baby step on road to replacing SkLazyFnPtr, SkLazyPtr, and SkOnce.

One of those very unusual times you get to use a function type,
not a function pointer type!

BUG=skia:

Review URL: https://codereview.chromium.org/1317263007
This commit is contained in:
mtklein 2015-09-08 08:19:33 -07:00 committed by Commit bot
parent a5f46e1821
commit bbd40183ae
2 changed files with 15 additions and 88 deletions
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66
src/core/SkLazyFnPtr.h
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@ -1,66 +0,0 @@
/*
* 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 SkLazyFnPtr_DEFINED
#define SkLazyFnPtr_DEFINED
/** Declare a lazily-chosen static function pointer of type F.
*
* Example usage:
*
* typedef int (*FooImpl)(int, int);
*
* static FooImpl choose_foo() { return ... };
*
* int Foo(int a, int b) {
* SK_DECLARE_STATIC_LAZY_FN_PTR(FooImpl, foo, choose_foo);
* return foo.get()(a, b);
* }
*
* You can think of SK_DECLARE_STATIC_LAZY_FN_PTR as a cheaper specialization of SkOnce.
* There is no mutex, and in the fast path, no memory barriers are issued.
*
* This must be used in a global or function scope, not as a class member.
*/
#define SK_DECLARE_STATIC_LAZY_FN_PTR(F, name, Choose) static Private::SkLazyFnPtr<F, Choose> name
// Everything below here is private implementation details. Don't touch, don't even look.
#include "SkAtomics.h"
namespace Private {
// This has no constructor and must be zero-initialized (the macro above does this).
template <typename F, F (*Choose)()>
class SkLazyFnPtr {
public:
F get() {
// First, try reading to see if it's already set.
F fn = (F)sk_atomic_load(&fPtr, sk_memory_order_relaxed);
if (fn != nullptr) {
return fn;
}
// We think it's not already set.
fn = Choose();
// No particular memory barriers needed; we're not guarding anything but the pointer itself.
F prev = (F)sk_atomic_cas(&fPtr, nullptr, (void*)fn);
// If prev != nullptr, someone snuck in and set fPtr concurrently.
// If prev == nullptr, we did write fn to fPtr.
return prev != nullptr ? prev : fn;
}
private:
void* fPtr;
};
} // namespace Private
#endif//SkLazyFnPtr_DEFINED

37
src/ports/SkFontHost_mac.cpp
View File

@ -28,7 +28,6 @@
#include "SkFontDescriptor.h"
#include "SkFontMgr.h"
#include "SkGlyph.h"
#include "SkLazyFnPtr.h"
#include "SkMaskGamma.h"
#include "SkMutex.h"
#include "SkOTTable_glyf.h"
@ -36,6 +35,7 @@
#include "SkOTTable_hhea.h"
#include "SkOTTable_loca.h"
#include "SkOTUtils.h"
#include "SkOncePtr.h"
#include "SkPaint.h"
#include "SkPath.h"
#include "SkSFNTHeader.h"
@ -770,34 +770,27 @@ SkScalerContext_Mac::SkScalerContext_Mac(SkTypeface_Mac* typeface,
fFUnitMatrix.preScale(emPerFUnit, -emPerFUnit);
}
extern "C" {
/** CTFontDrawGlyphs was introduced in 10.7. */
typedef void (*CTFontDrawGlyphsProc)(CTFontRef, const CGGlyph[], const CGPoint[],
size_t, CGContextRef);
/** This is an implementation of CTFontDrawGlyphs for 10.6. */
static void sk_legacy_CTFontDrawGlyphs(CTFontRef, const CGGlyph glyphs[], const CGPoint points[],
size_t count, CGContextRef cg)
{
/** This is an implementation of CTFontDrawGlyphs for 10.6; it was introduced in 10.7. */
static void legacy_CTFontDrawGlyphs(CTFontRef, const CGGlyph glyphs[], const CGPoint points[],
size_t count, CGContextRef cg) {
CGContextShowGlyphsAtPositions(cg, glyphs, points, count);
}
typedef decltype(legacy_CTFontDrawGlyphs) CTFontDrawGlyphsProc;
static CTFontDrawGlyphsProc* choose_CTFontDrawGlyphs() {
if (void* real = dlsym(RTLD_DEFAULT, "CTFontDrawGlyphs")) {
return (CTFontDrawGlyphsProc*)real;
}
return &legacy_CTFontDrawGlyphs;
}
CTFontDrawGlyphsProc SkChooseCTFontDrawGlyphs() {
CTFontDrawGlyphsProc realCTFontDrawGlyphs;
*reinterpret_cast<void**>(&realCTFontDrawGlyphs) = dlsym(RTLD_DEFAULT, "CTFontDrawGlyphs");
return realCTFontDrawGlyphs ? realCTFontDrawGlyphs : sk_legacy_CTFontDrawGlyphs;
};
SK_DECLARE_STATIC_LAZY_FN_PTR(CTFontDrawGlyphsProc, gCTFontDrawGlyphs, SkChooseCTFontDrawGlyphs);
SK_DECLARE_STATIC_ONCE_PTR(CTFontDrawGlyphsProc, gCTFontDrawGlyphs);
CGRGBPixel* Offscreen::getCG(const SkScalerContext_Mac& context, const SkGlyph& glyph,
CGGlyph glyphID, size_t* rowBytesPtr,
bool generateA8FromLCD)
{
CTFontDrawGlyphsProc ctFontDrawGlyphs = gCTFontDrawGlyphs.get();
bool generateA8FromLCD) {
auto ctFontDrawGlyphs = gCTFontDrawGlyphs.get(choose_CTFontDrawGlyphs);
if (!fRGBSpace) {
//It doesn't appear to matter what color space is specified.
@ -867,7 +860,7 @@ CGRGBPixel* Offscreen::getCG(const SkScalerContext_Mac& context, const SkGlyph&
fDoAA = !doAA;
fDoLCD = !doLCD;
if (sk_legacy_CTFontDrawGlyphs == ctFontDrawGlyphs) {
if (legacy_CTFontDrawGlyphs == ctFontDrawGlyphs) {
// CTFontDrawGlyphs will apply the font, font size, and font matrix to the CGContext.
// Our 'fake' one does not, so set up the CGContext here.
CGContextSetFont(fCG, context.fCGFont);