DM::NullSink

dm/DMSrcSink.h

 #ifndef DMSrcSink_DEFINED
 #define DMSrcSink_DEFINED
 
 #include "DMGpuSupport.h"
 #include "SkBBHFactory.h"
 #include "SkBBoxHierarchy.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkData.h"
 #include "SkGPipe.h"
+#include "SkNullCanvas.h"
 #include "SkPicture.h"
 #include "gm.h"
 
 namespace DM {
 
 // This is just convenience.  It lets you use either return "foo" or return SkStringPrintf(...).
 struct ImplicitString : public SkString {
     template <typename T>
     ImplicitString(const T& s) : SkString(s) {}
 };
@@ skipping 147 matching lines @@
 
     Error draw(const Src&, SkBitmap*, SkWStream*) const SK_OVERRIDE;
     int enclave() const SK_OVERRIDE { return fSink->enclave(); }
     const char* fileExtension() const SK_OVERRIDE { return fSink->fileExtension(); }
 private:
     const int                   fW, fH;
     SkAutoTDelete<SkBBHFactory> fFactory;
     SkAutoTDelete<Sink>         fSink;
 };
 
+class NullSink : public Sink {
+public:
+    Error draw(const Src& src, SkBitmap*, SkWStream* out) const SK_OVERRIDE {
+        (void)out->writeText("0\n");

[mtklein, 2015/01/29 20:00:12]

Is this so we don't try to encode an empty bitmap?

Sounds like we want the check to go from:

if (stream.len() > 0) {
  writeStream
} else {
  writeBitmap
}

to

if (stream.len() > 0) {
  writeStream
}
if (bitmap.sensible()) {
  writeBitmap
}

We don't really want to write any file for NullSink, do we?

[hal.canary, 2015/01/30 18:43:24]

Done.

+        return src.draw(SkCreateNullCanvas());
+    }
+    int enclave() const SK_OVERRIDE { return kAnyThread_Enclave; }
+    const char* fileExtension() const SK_OVERRIDE { return "null"; }

[mtklein, 2015/01/29 20:00:12]

or even, ""?

[hal.canary, 2015/01/30 18:43:24]

Done.

+};
+
 }  // namespace DM
 
 #endif//DMSrcSink_DEFINED