Bug 1034689 part 2 - Add AssignJSFlatString and use it. r=bz,terrence

william-wyliang · Jul 12, 2014 · 2a7ce8f · 2a7ce8f
1 parent e3e56e7
commit 2a7ce8f
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Showing 7 changed files with 60 additions and 20 deletions.
diff --git a/dom/base/nsJSTimeoutHandler.cpp b/dom/base/nsJSTimeoutHandler.cpp
@@ -349,8 +349,8 @@ nsJSScriptTimeoutHandler::Init(nsGlobalWindow *aWindow, bool *aIsInterval,
       return error.ErrorCode();
     }
 
-    mExpr.Append(JS_GetFlatStringChars(expr),
-                 JS_GetStringLength(JS_FORGET_STRING_FLATNESS(expr)));
+    MOZ_ASSERT(mExpr.IsEmpty());
+    AssignJSFlatString(mExpr, expr);
 
     // Get the calling location.
     const char *filename;

diff --git a/dom/base/nsJSUtils.h b/dom/base/nsJSUtils.h
@@ -157,6 +157,18 @@ AssignJSString(JSContext *cx, T &dest, JSString *s)
   return true;
 }
 
+inline void
+AssignJSFlatString(nsAString &dest, JSFlatString *s)
+{
+  size_t len = js::GetFlatStringLength(s);
+  static_assert(js::MaxStringLength < (1 << 28),
+                "Shouldn't overflow here or in SetCapacity");
+  dest.SetCapacity(len + 1);
+  js::CopyFlatStringChars(dest.BeginWriting(), s, len);
+  dest.BeginWriting()[len] = '\0';
+  dest.SetLength(len);
+}
+
 class nsAutoJSString : public nsAutoString
 {
 public:

diff --git a/dom/bindings/BindingUtils.cpp b/dom/bindings/BindingUtils.cpp
@@ -86,10 +86,13 @@ ThrowInvalidThis(JSContext* aCx, const JS::CallArgs& aArgs,
   MOZ_ASSERT(func);
   JS::Rooted<JSString*> funcName(aCx, JS_GetFunctionDisplayId(func));
   MOZ_ASSERT(funcName);
+  nsAutoJSString funcNameStr;
+  if (!funcNameStr.init(aCx, funcName)) {
+    return false;
+  }
   JS_ReportErrorNumberUC(aCx, GetErrorMessage, nullptr,
                          static_cast<const unsigned>(aErrorNumber),
-                         JS_GetStringCharsZ(aCx, funcName),
-                         ifaceName.get());
+                         funcNameStr.get(), ifaceName.get());
   return false;
 }
 

diff --git a/dom/bindings/Exceptions.cpp b/dom/bindings/Exceptions.cpp
@@ -394,9 +394,7 @@ NS_IMETHODIMP JSStackFrame::GetName(nsAString& aFunction)
   if (!mFunnameInitialized) {
     JS::FrameDescription& desc = mStackDescription->FrameAt(mIndex);
     if (JSFlatString *name = desc.funDisplayName()) {
-      mFunname.Assign(JS_GetFlatStringChars(name),
-                      // XXXbz Can't JS_GetStringLength on JSFlatString!
-                      JS_GetStringLength(JS_FORGET_STRING_FLATNESS(name)));
+      AssignJSFlatString(mFunname, name);
     }
     mFunnameInitialized = true;
   }

diff --git a/dom/plugins/base/nsNPAPIPlugin.cpp b/dom/plugins/base/nsNPAPIPlugin.cpp
@@ -1303,10 +1303,10 @@ _utf8fromidentifier(NPIdentifier id)
   }
 
   JSString *str = NPIdentifierToString(id);
+  nsAutoString autoStr;
+  AssignJSFlatString(autoStr, JS_ASSERT_STRING_IS_FLAT(str));
 
-  return
-    ToNewUTF8String(nsDependentString(::JS_GetInternedStringChars(str),
-                                      ::JS_GetStringLength(str)));
+  return ToNewUTF8String(autoStr);
 }
 
 int32_t

diff --git a/js/src/jsfriendapi.h b/js/src/jsfriendapi.h
@@ -813,6 +813,12 @@ GetStringLength(JSString *s)
     return reinterpret_cast<shadow::String*>(s)->length;
 }
 
+MOZ_ALWAYS_INLINE size_t
+GetFlatStringLength(JSFlatString *s)
+{
+    return reinterpret_cast<shadow::String*>(s)->length;
+}
+
 MOZ_ALWAYS_INLINE bool
 LinearStringHasLatin1Chars(JSLinearString *s)
 {
@@ -861,6 +867,12 @@ AtomToLinearString(JSAtom *atom)
     return reinterpret_cast<JSLinearString *>(atom);
 }
 
+MOZ_ALWAYS_INLINE JSLinearString *
+FlatStringToLinearString(JSFlatString *s)
+{
+    return reinterpret_cast<JSLinearString *>(s);
+}
+
 MOZ_ALWAYS_INLINE const JS::Latin1Char *
 GetLatin1AtomChars(const JS::AutoCheckCannotGC &nogc, JSAtom *atom)
 {
@@ -886,26 +898,37 @@ StringToLinearString(JSContext *cx, JSString *str)
     return reinterpret_cast<JSLinearString *>(str);
 }
 
-inline bool
-CopyStringChars(JSContext *cx, jschar *dest, JSString *s, size_t len)
+MOZ_ALWAYS_INLINE void
+CopyLinearStringChars(jschar *dest, JSLinearString *s, size_t len)
 {
-    JSLinearString *linear = StringToLinearString(cx, s);
-    if (!linear)
-        return false;
-
     JS::AutoCheckCannotGC nogc;
-    if (LinearStringHasLatin1Chars(linear)) {
-        const JS::Latin1Char *src = GetLatin1LinearStringChars(nogc, linear);
+    if (LinearStringHasLatin1Chars(s)) {
+        const JS::Latin1Char *src = GetLatin1LinearStringChars(nogc, s);
         for (size_t i = 0; i < len; i++)
             dest[i] = src[i];
     } else {
-        const jschar *src = GetTwoByteLinearStringChars(nogc, linear);
+        const jschar *src = GetTwoByteLinearStringChars(nogc, s);
         mozilla::PodCopy(dest, src, len);
     }
+}
 
+inline bool
+CopyStringChars(JSContext *cx, jschar *dest, JSString *s, size_t len)
+{
+    JSLinearString *linear = StringToLinearString(cx, s);
+    if (!linear)
+        return false;
+
+    CopyLinearStringChars(dest, linear, len);
     return true;
 }
 
+inline void
+CopyFlatStringChars(jschar *dest, JSFlatString *s, size_t len)
+{
+    CopyLinearStringChars(dest, FlatStringToLinearString(s), len);
+}
+
 JS_FRIEND_API(bool)
 GetPropertyNames(JSContext *cx, JSObject *obj, unsigned flags, JS::AutoIdVector *props);
 

diff --git a/xpcom/base/CycleCollectedJSRuntime.cpp b/xpcom/base/CycleCollectedJSRuntime.cpp
@@ -66,6 +66,7 @@
 #include "nsCycleCollectionParticipant.h"
 #include "nsCycleCollector.h"
 #include "nsDOMJSUtils.h"
+#include "nsJSUtils.h"
 
 #ifdef MOZ_CRASHREPORTER
 #include "nsExceptionHandler.h"
@@ -565,7 +566,10 @@ CycleCollectedJSRuntime::DescribeGCThing(bool aIsMarked, void* aThing,
       JSFunction* fun = JS_GetObjectFunction(obj);
       JSString* str = JS_GetFunctionDisplayId(fun);
       if (str) {
-        NS_ConvertUTF16toUTF8 fname(JS_GetInternedStringChars(str));
+        JSFlatString* flat = JS_ASSERT_STRING_IS_FLAT(str);
+        nsAutoString chars;
+        AssignJSFlatString(chars, flat);
+        NS_ConvertUTF16toUTF8 fname(chars);
         JS_snprintf(name, sizeof(name),
                     "JS Object (Function - %s)", fname.get());
       } else {