Add Platform methods for event tracing.

include/platform/Platform.h

@@ -20,8 +20,24 @@ class Platform
 {
   public:
 
+    // System --------------------------------------------------------------
+
+    // Monotonically increasing time in seconds from an arbitrary fixed point in the past.
+    // This function is expected to return at least millisecond-precision values. For this reason,
+    // it is recommended that the fixed point be no further in the past than the epoch.
+    virtual double monotonicallyIncreasingTime() { return 0; }
+
     // Tracing --------
 
+    // Get a pointer to the enabled state of the given trace category. The
+    // embedder can dynamically change the enabled state as trace event
+    // recording is started and stopped by the application. Only long-lived
+    // literal strings should be given as the category name. The implementation
+    // expects the returned pointer to be held permanently in a local static. If
+    // the unsigned char is non-zero, tracing is enabled. If tracing is enabled,
+    // addTraceEvent is expected to be called by the trace event macros.
+    virtual const unsigned char *getTraceCategoryEnabledFlag(const char *categoryName) { return 0; }
+
     typedef uint64_t TraceEventHandle;
 
     // Add a trace event to the platform tracing system. Depending on the actual
@@ -47,6 +63,7 @@ class Platform
     // - id optionally allows events of the same name to be distinguished from
     //   each other. For example, to trace the consutruction and destruction of
     //   objects, specify the pointer as the id parameter.
+    // - timestamp should be a time value returned from monotonicallyIncreasingTime.
     // - numArgs specifies the number of elements in argNames, argTypes, and
     //   argValues.
     // - argNames is the array of argument names. Use long-lived literal strings
@@ -84,15 +101,15 @@ class Platform
     }
 
     // Set the duration field of a COMPLETE trace event.
-    virtual void updateTraceEventDuration(const unsigned char* categoryEnabledFlag, const char* name, TraceEventHandle) { }
+    virtual void updateTraceEventDuration(const unsigned char *categoryEnabledFlag, const char *name, TraceEventHandle eventHandle) { }
 
     // Callbacks for reporting histogram data.
     // CustomCounts histogram has exponential bucket sizes, so that min=1, max=1000000, bucketCount=50 would do.
-    virtual void histogramCustomCounts(const char* name, int sample, int min, int max, int bucketCount) { }
+    virtual void histogramCustomCounts(const char *name, int sample, int min, int max, int bucketCount) { }
     // Enumeration histogram buckets are linear, boundaryValue should be larger than any possible sample value.
-    virtual void histogramEnumeration(const char* name, int sample, int boundaryValue) { }
+    virtual void histogramEnumeration(const char *name, int sample, int boundaryValue) { }
     // Unlike enumeration histograms, sparse histograms only allocate memory for non-empty buckets.
-    virtual void histogramSparse(const char* name, int sample) { }
+    virtual void histogramSparse(const char *name, int sample) { }
 
   protected:
     virtual ~Platform() { }

src/common/event_tracer.cpp

@@ -4,6 +4,9 @@
 
 #include "common/event_tracer.h"
 
+#include "common/debug.h"
+#include "platform/Platform.h"
+
 namespace gl
 {
 
@@ -15,8 +18,18 @@ AddTraceEventFunc g_addTraceEvent;
 namespace gl
 {
 
-const unsigned char* TraceGetTraceCategoryEnabledFlag(const char* name)
+const unsigned char *TraceGetTraceCategoryEnabledFlag(const char *name)
 {
+    angle::Platform *platform = ANGLEPlatformCurrent();
+    ASSERT(platform);
+
+    // TODO(jmadill): only use platform once it's working
+    const unsigned char *categoryEnabledFlag = platform->getTraceCategoryEnabledFlag(name);
+    if (categoryEnabledFlag != nullptr)
+    {
+        return categoryEnabledFlag;
+    }
+
     if (g_getCategoryEnabledFlag)
     {
         return g_getCategoryEnabledFlag(name);
@@ -29,7 +42,29 @@ void TraceAddTraceEvent(char phase, const unsigned char* categoryGroupEnabled, c
                         int numArgs, const char** argNames, const unsigned char* argTypes,
                         const unsigned long long* argValues, unsigned char flags)
 {
-    if (g_addTraceEvent)
+    angle::Platform *platform = ANGLEPlatformCurrent();
+    ASSERT(platform);
+
+    // TODO(jmadill): only use platform once it's working
+    double timestamp = platform->monotonicallyIncreasingTime();
+
+    if (timestamp != 0)
+    {
+        angle::Platform::TraceEventHandle handle =
+            platform->addTraceEvent(phase,
+                                    categoryGroupEnabled,
+                                    name,
+                                    id,
+                                    timestamp,
+                                    numArgs,
+                                    argNames,
+                                    argTypes,
+                                    argValues,
+                                    flags);
+        ASSERT(handle != 0);
+        UNUSED_ASSERTION_VARIABLE(handle);
+    }
+    else if (g_addTraceEvent)
     {
         g_addTraceEvent(phase, categoryGroupEnabled, name, id, numArgs, argNames, argTypes, argValues, flags);
     }