Add GrProgramElement base class for GrEffect with deferred exec ref.
BUG=skia:2889
R=robertphillips@google.com
Author: bsalomon@google.com
Review URL: https://codereview.chromium.org/537773004
diff --git a/include/gpu/GrProgramElement.h b/include/gpu/GrProgramElement.h
new file mode 100644
index 0000000..67135a3
--- /dev/null
+++ b/include/gpu/GrProgramElement.h
@@ -0,0 +1,94 @@
+/*
+ * 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 GrProgramElement_DEFINED
+#define GrProgramElement_DEFINED
+
+#include "SkRefCnt.h"
+#include "SkTArray.h"
+
+class GrProgramResource;
+
+/**
+ * Base class for GrEffect (and future GrGeometryProcessor). GrDrawState uses this to manage
+ * transitioning a GrEffect from being owned by a client to being scheduled for execution. It
+ * converts resources owned by the effect from being ref'ed to having pending reads/writes.
+ *
+ * All GrGpuResource objects owned by a GrProgramElement or derived classes (either directly or
+ * indirectly) must be wrapped in a GrProgramResource and registered with the GrProgramElement using
+ * addGrProgramResource(). This allows the regular refs to be converted to pending IO events
+ * when the program element is scheduled for deferred execution.
+ */
+class GrProgramElement : public SkNoncopyable {
+public:
+ SK_DECLARE_INST_COUNT_ROOT(GrProgramElement)
+
+ virtual ~GrProgramElement() {
+ // fRefCnt can be one when an effect is created statically using GR_CREATE_STATIC_EFFECT
+ SkASSERT((0 == fRefCnt || 1 == fRefCnt) && 0 == fPendingExecutions);
+ // Set to invalid values.
+ SkDEBUGCODE(fRefCnt = fPendingExecutions = -10;)
+ }
+
+ void ref() const {
+ // Once the ref cnt reaches zero it should never be ref'ed again.
+ SkASSERT(fRefCnt > 0);
+ this->validate();
+ ++fRefCnt;
+ }
+
+ void unref() const {
+ this->validate();
+ --fRefCnt;
+ if (0 == fRefCnt && 0 == fPendingExecutions) {
+ SkDELETE(this);
+ }
+ }
+
+ void validate() const {
+#ifdef SK_DEBUG
+ SkASSERT(fRefCnt >= 0);
+ SkASSERT(fPendingExecutions >= 0);
+ SkASSERT(fRefCnt + fPendingExecutions > 0);
+#endif
+ }
+
+protected:
+ GrProgramElement() : fRefCnt(1), fPendingExecutions(0) {}
+
+ /** Subclasses registers their resources using this function. It is assumed the GrProgramResouce
+ is and will remain owned by the subclass and this function will retain a raw ptr. Once a
+ GrProgramResource is registered its setResource must not be called.
+ */
+ void addProgramResource(const GrProgramResource* res) {
+ fProgramResources.push_back(res);
+ }
+
+private:
+ void convertRefToPendingExecution() const;
+
+ void completedExecution() const {
+ this->validate();
+ --fPendingExecutions;
+ if (0 == fRefCnt && 0 == fPendingExecutions) {
+ SkDELETE(this);
+ }
+ }
+
+ mutable int32_t fRefCnt;
+ // Count of deferred executions not yet issued to the 3D API.
+ mutable int32_t fPendingExecutions;
+
+ SkSTArray<4, const GrProgramResource*, true> fProgramResources;
+
+ // Only this class can access convertRefToPendingExecution() and completedExecution().
+ template <typename T> friend class GrProgramElementRef;
+
+ typedef SkNoncopyable INHERITED;
+};
+
+#endif