Add an nsIGfxInfo for describing active crash guards. (bug 1270894 part 1, r=milan)

gfx/src/DriverCrashGuard.cpp

@@ -23,11 +23,24 @@ namespace mozilla {
 namespace gfx {
 
 static const size_t NUM_CRASH_GUARD_TYPES = size_t(CrashGuardType::NUM_TYPES);
-static const char* sCrashGuardNames[NUM_CRASH_GUARD_TYPES] = {
+static const char* sCrashGuardNames[] = {
   "d3d11layers",
   "d3d9video",
   "glcontext",
+  "d3d11video",
 };
+static_assert(MOZ_ARRAY_LENGTH(sCrashGuardNames) == NUM_CRASH_GUARD_TYPES,
+              "CrashGuardType updated without a name string");
+
+static inline void
+BuildCrashGuardPrefName(CrashGuardType aType, nsCString& aOutPrefName)
+{
+  MOZ_ASSERT(aType < CrashGuardType::NUM_TYPES);
+  MOZ_ASSERT(sCrashGuardNames[size_t(aType)]);
+
+  aOutPrefName.Assign("gfx.crash-guard.status.");
+  aOutPrefName.Append(sCrashGuardNames[size_t(aType)]);
+}
 
 DriverCrashGuard::DriverCrashGuard(CrashGuardType aType, dom::ContentParent* aContentParent)
  : mType(aType)
@@ -36,10 +49,7 @@ DriverCrashGuard::DriverCrashGuard(CrashGuardType aType, dom::ContentParent* aCo
  , mGuardActivated(false)
  , mCrashDetected(false)
 {
-  MOZ_ASSERT(mType < CrashGuardType::NUM_TYPES);
-
-  mStatusPref.Assign("gfx.crash-guard.status.");
-  mStatusPref.Append(sCrashGuardNames[size_t(mType)]);
+  BuildCrashGuardPrefName(aType, mStatusPref);
 }
 
 void
@@ -53,15 +63,29 @@ DriverCrashGuard::InitializeIfNeeded()
   Initialize();
 }
 
-void
-DriverCrashGuard::Initialize()
+static inline bool
+AreCrashGuardsEnabled()
 {
 #ifdef NIGHTLY_BUILD
   // We only use the crash guard on non-nightly channels, since the nightly
   // channel is for development and having graphics features perma-disabled
   // is rather annoying.
-  return;
+  return false;
+#else
+  // Check to see if all guards have been disabled through the environment.
+  if (gfxEnv::DisableCrashGuard()) {
+    return false;
+  }
+  return true;
 #endif
+}
+
+void
+DriverCrashGuard::Initialize()
+{
+  if (!AreCrashGuardsEnabled()) {
+    return;
+  }
 
   // Using DriverCrashGuard off the main thread currently does not work. Under
   // e10s it could conceivably work by dispatching the IPC calls via the main
@@ -71,11 +95,6 @@ DriverCrashGuard::Initialize()
     return;
   }
 
-  // Check to see if all guards have been disabled through the environment.
-  if (gfxEnv::DisableCrashGuard()) {
-    return;
-  }
-
   mGfxInfo = services::GetGfxInfo();
 
   if (XRE_IsContentProcess()) {
@@ -366,6 +385,31 @@ DriverCrashGuard::FlushPreferences()
   }
 }
 
+void
+DriverCrashGuard::ForEachActiveCrashGuard(const CrashGuardCallback& aCallback)
+{
+  if (!AreCrashGuardsEnabled()) {
+    // Even if guards look active (via prefs), they can be ignored if globally
+    // disabled.
+    return;
+  }
+
+  for (size_t i = 0; i < NUM_CRASH_GUARD_TYPES; i++) {
+    CrashGuardType type = static_cast<CrashGuardType>(i);
+
+    nsCString prefName;
+    BuildCrashGuardPrefName(type, prefName);
+
+    auto status =
+      static_cast<DriverInitStatus>(Preferences::GetInt(prefName.get(), 0));
+    if (status != DriverInitStatus::Crashed) {
+      continue;
+    }
+
+    aCallback(sCrashGuardNames[i], prefName.get());
+  }
+}
+
 D3D11LayersCrashGuard::D3D11LayersCrashGuard(dom::ContentParent* aContentParent)
  : DriverCrashGuard(CrashGuardType::D3D11Layers, aContentParent)
 {

gfx/src/DriverCrashGuard.h

@@ -9,6 +9,7 @@
 #include "nsIGfxInfo.h"
 #include "nsIFile.h"
 #include "nsString.h"
+#include "mozilla/Function.h"
 #include <string>
 
 namespace mozilla {
@@ -40,6 +41,10 @@ enum class CrashGuardType : uint32_t
   D3D9Video,
   GLContext,
   D3D11Video,
+  // Add new entries above this line, update the name array in
+  // DriverCrashGuard.cpp, and make sure to add an entry in
+  // ContentParent.cpp.
+
   NUM_TYPES
 };
 
@@ -78,6 +83,10 @@ public:
     Proxy
   };
 
+  typedef mozilla::function<void(const char* aName, const char* aPrefName)>
+    CrashGuardCallback;
+  static void ForEachActiveCrashGuard(const CrashGuardCallback& aCallback);
+
 protected:
   virtual void Initialize();
   virtual bool UpdateEnvironment() = 0;

widget/GfxInfoBase.cpp

@@ -34,6 +34,7 @@
 #include "gfxPrefs.h"
 #include "gfxPlatform.h"
 #include "gfxConfig.h"
+#include "DriverCrashGuard.h"
 
 #if defined(MOZ_CRASHREPORTER)
 #include "nsExceptionHandler.h"
@@ -1337,6 +1338,35 @@ GfxInfoBase::InitFeatureObject(JSContext* aCx,
   return true;
 }
 
+nsresult
+GfxInfoBase::GetActiveCrashGuards(JSContext* aCx, JS::MutableHandle<JS::Value> aOut)
+{
+  JS::Rooted<JSObject*> array(aCx, JS_NewArrayObject(aCx, 0));
+  if (!array) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  aOut.setObject(*array);
+
+  DriverCrashGuard::ForEachActiveCrashGuard([&](const char* aName,
+                                                const char* aPrefName) -> void {
+    JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+    if (!obj) {
+      return;
+    }
+    if (!SetJSPropertyString(aCx, obj, "type", aName)) {
+      return;
+    }
+    if (!SetJSPropertyString(aCx, obj, "prefName", aPrefName)) {
+      return;
+    }
+    if (!AppendJSElement(aCx, array, obj)) {
+      return;
+    }
+  });
+
+  return NS_OK;
+}
+
 GfxInfoCollectorBase::GfxInfoCollectorBase()
 {
   GfxInfoBase::AddCollector(this);

widget/GfxInfoBase.h

@@ -57,6 +57,7 @@ public:
   NS_IMETHOD GetInfo(JSContext*, JS::MutableHandle<JS::Value>) override;
   NS_IMETHOD GetFeatures(JSContext*, JS::MutableHandle<JS::Value>) override;
   NS_IMETHOD GetFeatureLog(JSContext*, JS::MutableHandle<JS::Value>) override;
+  NS_IMETHOD GetActiveCrashGuards(JSContext*, JS::MutableHandle<JS::Value>) override;
 
   // Initialization function. If you override this, you must call this class's
   // version of Init first.

widget/nsIGfxInfo.idl

@@ -224,5 +224,20 @@ interface nsIGfxInfo : nsISupports
   //   }
   [implicit_jscontext]
   jsval getFeatures();
+
+  // Returns an array listing any active crash guards.
+  //
+  //   [
+  //     {
+  //       // Type is one of "d3d11layers", "d3d9video", "glcontext",
+  //       // or "d3d11video".
+  //       "type":        "<identifier>",
+  //
+  //       // Preference that must be deleted/reset to retrigger the guard.
+  //       "prefName":    "<preference>",
+  //     }
+  //   ]
+  [implicit_jscontext]
+  jsval getActiveCrashGuards();
 };