Add support for Semaphores (gpu waiting on gpu) in Ganesh

BUG=skia:

Change-Id: I4324b65bc50a3dfd90372459899870d5f1952fdc
Reviewed-on: https://skia-review.googlesource.com/9120
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/src/gpu/GrSemaphore.h b/src/gpu/GrSemaphore.h
new file mode 100644
index 0000000000..bdeff09ec2
--- /dev/null
+++ b/src/gpu/GrSemaphore.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrSemaphore_DEFINED
+#define GrSemaphore_DEFINED
+
+#include "SkRefCnt.h"
+
+class GrGpu;
+
+class GrSemaphore : public SkRefCnt {
+public:
+    // This function should only be used in the case of exporting and importing a GrSemaphore object
+    // from one GrContext to another. When exporting, the GrSemaphore should be set to a null GrGpu,
+    // and when importing it should be set to the GrGpu of the current context. Once exported, a
+    // GrSemaphore should not be used with its old context.
+    void resetGpu(const GrGpu* gpu) { fGpu = gpu; }
+
+protected:
+    explicit GrSemaphore(const GrGpu* gpu) : fGpu(gpu) {}
+
+    const GrGpu* fGpu;
+};
+
+#endif