From 71d2d8d00499c9b614e1ef9601bef0dd1497fffc Mon Sep 17 00:00:00 2001
From: Alessio Placitelli <alessio.placitelli@gmail.com>
Date: Tue, 7 Jan 2014 10:18:30 -0500
Subject: [PATCH] Bug 950762 - Add fallible AppendUTF16toUTF8 and make
 DOMParser::ParseFromString fallible. r=jst, r=bsmedberg

---
 content/base/src/DOMParser.cpp        | 10 +++++++---
 xpcom/string/public/nsReadableUtils.h |  2 ++
 xpcom/string/src/nsReadableUtils.cpp  | 15 ++++++++++++++-
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/content/base/src/DOMParser.cpp b/content/base/src/DOMParser.cpp
index 0dfb96f0e75b..65762036c45d 100644
--- a/content/base/src/DOMParser.cpp
+++ b/content/base/src/DOMParser.cpp
@@ -106,17 +106,21 @@ DOMParser::ParseFromString(const nsAString& str,
     return rv;
   }
 
-  NS_ConvertUTF16toUTF8 data(str);
+  nsAutoCString utf8str;
+  // Convert from UTF16 to UTF8 using fallible allocations
+  if (!AppendUTF16toUTF8(str, utf8str, mozilla::fallible_t())) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
 
   // The new stream holds a reference to the buffer
   nsCOMPtr<nsIInputStream> stream;
   rv = NS_NewByteInputStream(getter_AddRefs(stream),
-                             data.get(), data.Length(),
+                             utf8str.get(), utf8str.Length(),
                              NS_ASSIGNMENT_DEPEND);
   if (NS_FAILED(rv))
     return rv;
 
-  return ParseFromStream(stream, "UTF-8", data.Length(), contentType, aResult);
+  return ParseFromStream(stream, "UTF-8", utf8str.Length(), contentType, aResult);
 }
 
 already_AddRefed<nsIDocument>
diff --git a/xpcom/string/public/nsReadableUtils.h b/xpcom/string/public/nsReadableUtils.h
index a44514524ff4..fd9b02895f37 100644
--- a/xpcom/string/public/nsReadableUtils.h
+++ b/xpcom/string/public/nsReadableUtils.h
@@ -46,6 +46,8 @@ void LossyAppendUTF16toASCII( const char16_t* aSource, nsACString& aDest );
 void AppendASCIItoUTF16( const char* aSource, nsAString& aDest );
 
 void AppendUTF16toUTF8( const nsAString& aSource, nsACString& aDest );
+bool AppendUTF16toUTF8( const nsAString& aSource, nsACString& aDest,
+                        const mozilla::fallible_t& ) NS_WARN_UNUSED_RESULT;
 void AppendUTF8toUTF16( const nsACString& aSource, nsAString& aDest );
 bool AppendUTF8toUTF16( const nsACString& aSource, nsAString& aDest,
                         const mozilla::fallible_t& ) NS_WARN_UNUSED_RESULT;
diff --git a/xpcom/string/src/nsReadableUtils.cpp b/xpcom/string/src/nsReadableUtils.cpp
index afceee48a3f1..35cf83ab9b24 100644
--- a/xpcom/string/src/nsReadableUtils.cpp
+++ b/xpcom/string/src/nsReadableUtils.cpp
@@ -126,6 +126,15 @@ AppendASCIItoUTF16( const char* aSource, nsAString& aDest )
 
 void
 AppendUTF16toUTF8( const nsAString& aSource, nsACString& aDest )
+{
+  if (!AppendUTF16toUTF8(aSource, aDest, mozilla::fallible_t())) {
+    NS_ABORT_OOM(aDest.Length() + aSource.Length());
+  }
+}
+
+bool
+AppendUTF16toUTF8( const nsAString& aSource, nsACString& aDest,
+                   const mozilla::fallible_t& )
   {
     nsAString::const_iterator source_start, source_end;
     CalculateUTF8Size calculator;
@@ -139,7 +148,9 @@ AppendUTF16toUTF8( const nsAString& aSource, nsACString& aDest )
         uint32_t old_dest_length = aDest.Length();
 
         // Grow the buffer if we need to.
-        aDest.SetLength(old_dest_length + count);
+        if (!aDest.SetLength(old_dest_length + count, mozilla::fallible_t())) {
+          return false;
+        }
 
         // All ready? Time to convert
 
@@ -151,6 +162,8 @@ AppendUTF16toUTF8( const nsAString& aSource, nsACString& aDest )
                      "Unexpected disparity between CalculateUTF8Size and "
                      "ConvertUTF16toUTF8");
       }
+
+    return true;
   }
 
 void