Bug 1513975 - Add ChromeUtils.releaseAssert for Chrome JS, r=kmag

Differential Revision: https://phabricator.services.mozilla.com/D15607

--HG--
extra : moz-landing-system : lando

dom/base/ChromeUtils.cpp

@@ -26,6 +26,7 @@
 #include "nsThreadUtils.h"
 #include "mozJSComponentLoader.h"
 #include "GeckoProfiler.h"
+#include "nsIException.h"
 
 namespace mozilla {
 namespace dom {
@@ -132,6 +133,34 @@ namespace dom {
   aRetval.set(buffer);
 }
 
+/* static */ void ChromeUtils::ReleaseAssert(GlobalObject& aGlobal,
+                                             bool aCondition,
+                                             const nsAString& aMessage) {
+  // If the condition didn't fail, which is the likely case, immediately return.
+  if (MOZ_LIKELY(aCondition)) {
+    return;
+  }
+
+  // Extract the current stack from the JS runtime to embed in the crash reason.
+  nsAutoString filename;
+  uint32_t lineNo = 0;
+
+  if (nsCOMPtr<nsIStackFrame> location = GetCurrentJSStack(1)) {
+    location->GetFilename(aGlobal.Context(), filename);
+    lineNo = location->GetLineNumber(aGlobal.Context());
+  } else {
+    filename.Assign(NS_LITERAL_STRING("<unknown>"));
+  }
+
+  // Convert to utf-8 for adding as the MozCrashReason.
+  NS_ConvertUTF16toUTF8 filenameUtf8(filename);
+  NS_ConvertUTF16toUTF8 messageUtf8(aMessage);
+
+  // Actually crash.
+  MOZ_CRASH_UNSAFE_PRINTF("Failed ChromeUtils.releaseAssert(\"%s\") @ %s:%u",
+                          messageUtf8.get(), filenameUtf8.get(), lineNo);
+}
+
 /* static */ void ChromeUtils::WaiveXrays(GlobalObject& aGlobal,
                                           JS::HandleValue aVal,
                                           JS::MutableHandleValue aRetval,

dom/base/ChromeUtils.h

@@ -69,6 +69,9 @@ class ChromeUtils {
                               JS::MutableHandle<JSObject*> aRetval,
                               ErrorResult& aRv);
 
+  static void ReleaseAssert(GlobalObject& aGlobal, bool aCondition,
+                            const nsAString& aMessage);
+
   static void OriginAttributesToSuffix(
       GlobalObject& aGlobal, const dom::OriginAttributesDictionary& aAttrs,
       nsCString& aSuffix);

dom/chrome-webidl/ChromeUtils.webidl

@@ -105,6 +105,18 @@ namespace ChromeUtils {
   ArrayBuffer base64URLDecode(ByteString string,
                               Base64URLDecodeOptions options);
 
+  /**
+   * Cause the current process to fatally crash unless the given condition is
+   * true. This is similar to MOZ_RELEASE_ASSERT in C++ code.
+   *
+   * WARNING: This message is included publicly in the crash report, and must
+   * not contain private information.
+   *
+   * Crash report will be augmented with the current JS stack information.
+   */
+  void releaseAssert(boolean condition,
+                     optional DOMString message = "<no message>");
+
 #ifdef NIGHTLY_BUILD
 
   /**