First pass at Comment API

https://codereview.chromium.org/13957009/



git-svn-id: http://skia.googlecode.com/svn/trunk@9310 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 39 insertions, 1 deletions

diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 2bf5a54a51..821f86b5ad 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -852,7 +852,24 @@ public:
         subclasses like SkPicture's recording canvas, that can store the data
         and then play it back later (via another call to drawData).
      */
-    virtual void drawData(const void* data, size_t length);
+    virtual void drawData(const void* data, size_t length) {
+        // do nothing. Subclasses may do something with the data
+    }
+
+    /** Add comments. beginCommentGroup/endCommentGroup open/close a new group. 
+        Each comment added via addComment is notionally attached to its 
+        enclosing group. Top-level comments simply belong to no group.
+     */
+    virtual void beginCommentGroup(const char* description) {
+        // do nothing. Subclasses may do something
+    }
+    virtual void addComment(const char* kywd, const char* value) {
+        // do nothing. Subclasses may do something
+    }
+    virtual void endCommentGroup() {
+        // do nothing. Subclasses may do something
+    }
+
 
     //////////////////////////////////////////////////////////////////////////
 
@@ -1138,4 +1155,25 @@ private:
     int         fSaveCount;
 };
 
+/** Stack helper class to automatically open and close a comment block
+ */
+class SkAutoCommentBlock : SkNoncopyable {
+public:
+    SkAutoCommentBlock(SkCanvas* canvas, const char* description) {
+        fCanvas = canvas;
+        if (NULL != fCanvas) {
+            fCanvas->beginCommentGroup(description);
+        }
+    }
+
+    ~SkAutoCommentBlock() {
+        if (NULL != fCanvas) {
+            fCanvas->endCommentGroup();
+        }
+    }
+
+private:
+    SkCanvas* fCanvas;
+};
+
 #endif