Change GrCFResource to sk_cf_obj and move to include/ports.

This makes GrCFResource a template class with similar semantics to sk_sp.

Change-Id: I9ae9988dac6b39477b16d65591ef6fff44903c36
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/218376
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Mike Reed <reed@google.com>

include/gpu/mtl/GrMtlTypes.h

@@ -9,8 +9,7 @@
 #define GrMtlTypes_DEFINED
 
 #include "include/gpu/GrTypes.h"
-
-#import <CoreFoundation/CoreFoundation.h>
+#include "include/ports/SkCFObject.h"
 
 /**
  * Declares typedefs for Metal types used in Ganesh cpp code
@@ -19,72 +18,6 @@ typedef unsigned int GrMTLPixelFormat;
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/**
- * Wrapper class for managing lifetime of CoreFoundation objects. It will call
- * CFRetain and CFRelease appropriately on creation, assignment, and deletion.
- */
-class GrCFResource {
-public:
-    GrCFResource() : fCFObject(nullptr) {}
-    explicit GrCFResource(const void* resource) {
-        fCFObject = resource;
-        if (fCFObject) {
-            CFRetain(fCFObject);
-        }
-    }
-    GrCFResource(const GrCFResource& that) {
-        fCFObject = that.fCFObject;
-        if (fCFObject) {
-            CFRetain(fCFObject);
-        }
-    }
-    ~GrCFResource() {
-        if (fCFObject) {
-            CFRelease(fCFObject);
-        }
-        fCFObject = nullptr;
-    }
-
-    GrCFResource& operator=(const void* resource) {
-        this->assign(resource);
-        return *this;
-    }
-    GrCFResource& operator=(const GrCFResource& that) {
-        this->assign(that.fCFObject);
-        return *this;
-    }
-
-    const void* get() const { return fCFObject; }
-
-    /* Explicitly retains ownership of the object rather than transferring it.
-     * For translating from other shared_ptr/unique_ptr classes that wish to
-     * maintain their own ownership.
-     */
-    void retain(const void* resource) {
-        this->assign(resource);
-    }
-
-    bool operator==(const GrCFResource& that) const {
-        return this->fCFObject == that.fCFObject;
-    }
-    bool operator!=(const GrCFResource& that) const {
-        return this->fCFObject != that.fCFObject;
-    }
-
-private:
-    void assign(const void* resource) {
-        if (resource) {
-            CFRetain(resource);
-        }
-        if (fCFObject) {
-            CFRelease(fCFObject);
-        }
-        fCFObject = resource;
-    }
-
-    const void* fCFObject;
-};
-
 /**
  * Types for interacting with Metal resources created externally to Skia.
  * This is used by GrBackendObjects.
@@ -93,7 +26,7 @@ struct GrMtlTextureInfo {
 public:
     GrMtlTextureInfo() {}
 
-    GrCFResource fTexture;
+    sk_cf_obj<const void*> fTexture;
 
     bool operator==(const GrMtlTextureInfo& that) const {
         return fTexture == that.fTexture;

include/ports/SkCFObject.h

@@ -0,0 +1,138 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkCFObject_DEFINED
+#define SkCFObject_DEFINED
+
+#if defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
+
+#import <CoreFoundation/CoreFoundation.h>
+
+/**
+ * Wrapper class for managing lifetime of CoreFoundation objects. It will call
+ * CFRetain and CFRelease appropriately on creation, assignment, and deletion.
+ * Based on sk_sp<>.
+ */
+template <typename T> static inline T SkCFSafeRetain(T obj) {
+    if (obj) {
+        CFRetain(obj);
+    }
+    return obj;
+}
+
+template <typename T> static inline void SkCFSafeRelease(T obj) {
+    if (obj) {
+        CFRelease(obj);
+    }
+}
+
+template <typename T> class sk_cf_obj {
+public:
+    using element_type = T;
+
+    constexpr sk_cf_obj() : fObject(nullptr) {}
+
+    /**
+     *  Shares the underlying object by calling CFRetain(), so that both the argument and the newly
+     *  created sk_cf_obj both have a reference to it.
+     */
+    sk_cf_obj(const sk_cf_obj<T>& that) : fObject(SkCFSafeRetain(that.get())) {}
+
+    /**
+     *  Move the underlying object from the argument to the newly created sk_cf_obj. Afterwards only
+     *  the new sk_cf_obj will have a reference to the object, and the argument will point to null.
+     *  No call to CFRetain() or CFRelease() will be made.
+     */
+    sk_cf_obj(sk_cf_obj<T>&& that) : fObject(that.release()) {}
+
+    /**
+     *  Adopt the bare object into the newly created sk_cf_obj.
+     *  No call to CFRetain() or CFRelease() will be made.
+     */
+    explicit sk_cf_obj(T obj) {
+        fObject = obj;
+    }
+
+    /**
+     *  Calls CFRelease() on the underlying object pointer.
+     */
+    ~sk_cf_obj() {
+        SkCFSafeRelease(fObject);
+        SkDEBUGCODE(fObject = nullptr);
+    }
+
+    /**
+     *  Shares the underlying object referenced by the argument by calling CFRetain() on it. If this
+     *  sk_cf_obj previously had a reference to an object (i.e. not null) it will call CFRelease()
+     *  on that object.
+     */
+    sk_cf_obj<T>& operator=(const sk_cf_obj<T>& that) {
+        if (this != &that) {
+            this->reset(SkCFSafeRetain(that.get()));
+        }
+        return *this;
+    }
+
+    /**
+     *  Move the underlying object from the argument to the sk_cf_obj. If the sk_cf_obj
+     * previously held a reference to another object, CFRelease() will be called on that object.
+     * No call to CFRetain() will be made.
+     */
+    sk_cf_obj<T>& operator=(sk_cf_obj<T>&& that) {
+        this->reset(that.release());
+        return *this;
+    }
+
+    T get() const { return fObject; }
+
+    /**
+     *  Adopt the new object, and call CFRelease() on any previously held object (if not null).
+     *  No call to CFRetain() will be made.
+     */
+    void reset(T object = nullptr) {
+        T oldObject = fObject;
+        fObject = object;
+        SkCFSafeRelease(oldObject);
+    }
+
+    /**
+     *  Shares the new object by calling CFRetain() on it. If this sk_cf_obj previously had a
+     *  reference to an object (i.e. not null) it will call CFRelease() on that object.
+     */
+    void retain(T object) {
+        if (this->fObject != object) {
+            this->reset(SkCFSafeRetain(object));
+        }
+    }
+
+    /**
+     *  Return the original object, and set the internal object to nullptr.
+     *  The caller must assume ownership of the object, and manage its reference count directly.
+     *  No call to CFRelease() will be made.
+     */
+    T SK_WARN_UNUSED_RESULT release() {
+        T obj = fObject;
+        fObject = nullptr;
+        return obj;
+    }
+
+private:
+    T fObject;
+};
+
+template <typename T> inline bool operator==(const sk_cf_obj<T>& a,
+                                             const sk_cf_obj<T>& b) {
+    return a.get() == b.get();
+}
+
+template <typename T> inline bool operator!=(const sk_cf_obj<T>& a,
+                                             const sk_cf_obj<T>& b) {
+    return a.get() != b.get();
+}
+
+#endif  // SK_BUILD_FOR_MAC || SK_BUILD_FOR_IOS
+#endif  // SkCFOBject_DEFINED

src/gpu/mtl/GrMtlGpu.mm

@@ -690,7 +690,7 @@ bool GrMtlGpu::createTestingOnlyMtlTextureInfo(GrPixelConfig config, MTLPixelFor
     [cmdBuffer waitUntilCompleted];
     transferBuffer = nil;
 
-    info->fTexture = GrGetPtrFromId(testTexture);
+    info->fTexture.reset(GrRetainPtrFromId(testTexture));
 
     return true;
 }

src/gpu/mtl/GrMtlRenderTarget.mm

@@ -54,7 +54,7 @@ GrMtlRenderTarget::~GrMtlRenderTarget() {
 
 GrBackendRenderTarget GrMtlRenderTarget::getBackendRenderTarget() const {
     GrMtlTextureInfo info;
-    info.fTexture = GrGetPtrFromId(fRenderTexture);
+    info.fTexture.reset(GrRetainPtrFromId(fRenderTexture));
     return GrBackendRenderTarget(this->width(), this->height(), fRenderTexture.sampleCount, info);
 }
 

src/gpu/mtl/GrMtlTexture.mm

@@ -98,7 +98,7 @@ GrBackendTexture GrMtlTexture::getBackendTexture() const {
     GrMipMapped mipMapped = fTexture.mipmapLevelCount > 1 ? GrMipMapped::kYes
                                                           : GrMipMapped::kNo;
     GrMtlTextureInfo info;
-    info.fTexture = GrGetPtrFromId(fTexture);
+    info.fTexture.reset(GrRetainPtrFromId(fTexture));
     return GrBackendTexture(this->width(), this->height(), mipMapped, info);
 }
 

src/gpu/mtl/GrMtlUtil.h

@@ -53,6 +53,15 @@ SK_ALWAYS_INLINE const void* GrGetPtrFromId(id idObject) {
     return (__bridge const void*)idObject;
 }
 
+/**
+ * Returns a const void* to whatever the id object is pointing to.
+ * Will call CFRetain on the object.
+ */
+SK_ALWAYS_INLINE const void* GrRetainPtrFromId(id idObject) {
+    return (__bridge_retained const void*)idObject;
+}
+
+
 /**
  * Returns a MTLTextureDescriptor which describes the MTLTexture. Useful when creating a duplicate
  * MTLTexture without the same storage allocation.

tools/sk_app/MetalWindowContext.mm

@@ -84,7 +84,7 @@ sk_sp<SkSurface> MetalWindowContext::getBackbufferSurface() {
         fCurrentDrawable = [fMetalLayer nextDrawable];
 
         GrMtlTextureInfo fbInfo;
-        fbInfo.fTexture = fCurrentDrawable.texture;
+        fbInfo.fTexture.reset(CFRetain((__bridge const void*)(fCurrentDrawable.texture)));
 
         GrBackendRenderTarget backendRT(fWidth,
                                         fHeight,