From 6a8c4ffada73e1a8d7eb2265f003cbfc3ca263ab Mon Sep 17 00:00:00 2001
From: Kyle Huey <khuey@kylehuey.com>
Date: Tue, 19 Jul 2011 09:27:46 -0700
Subject: [PATCH] Bug 664254: Make DOM File objects implement nsIMutable so
 they can be immutabilized for sharing across threads. r=sicking

---
 content/base/public/nsDOMFile.h | 16 +++++++++++-----
 content/base/src/nsDOMFile.cpp  | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/content/base/public/nsDOMFile.h b/content/base/public/nsDOMFile.h
index 351898eba774..691a848d4ad4 100644
--- a/content/base/public/nsDOMFile.h
+++ b/content/base/public/nsDOMFile.h
@@ -46,6 +46,7 @@
 #include "nsIDOMFileError.h"
 #include "nsIInputStream.h"
 #include "nsIJSNativeInitializer.h"
+#include "nsIMutable.h"
 #include "nsCOMArray.h"
 #include "nsCOMPtr.h"
 #include "mozilla/AutoRestore.h"
@@ -66,21 +67,22 @@ class nsIBlobBuilder;
 nsresult NS_NewBlobBuilder(nsISupports* *aSupports);
 
 class nsDOMFileBase : public nsIDOMFile,
-                      public nsIXHRSendable
+                      public nsIXHRSendable,
+                      public nsIMutable
 {
 public:
 
   nsDOMFileBase(const nsAString& aName, const nsAString& aContentType,
                 PRUint64 aLength)
-    : mIsFile(true), mContentType(aContentType), mName(aName),
-      mStart(0), mLength(aLength)
+    : mIsFile(true), mImmutable(false), mContentType(aContentType),
+      mName(aName), mStart(0), mLength(aLength)
   {
     // Ensure non-null mContentType by default
     mContentType.SetIsVoid(PR_FALSE);
   }
 
   nsDOMFileBase(const nsAString& aContentType, PRUint64 aLength)
-    : mIsFile(false), mContentType(aContentType),
+    : mIsFile(false), mImmutable(false), mContentType(aContentType),
       mStart(0), mLength(aLength)
   {
     // Ensure non-null mContentType by default
@@ -89,7 +91,7 @@ public:
 
   nsDOMFileBase(const nsAString& aContentType,
                 PRUint64 aStart, PRUint64 aLength)
-    : mIsFile(false), mContentType(aContentType),
+    : mIsFile(false), mImmutable(false), mContentType(aContentType),
       mStart(aStart), mLength(aLength)
   {
     NS_ASSERTION(aLength != PR_UINT64_MAX,
@@ -108,6 +110,7 @@ public:
   NS_DECL_NSIDOMBLOB
   NS_DECL_NSIDOMFILE
   NS_DECL_NSIXHRSENDABLE
+  NS_DECL_NSIMUTABLE
 
 protected:
   bool IsSizeUnknown()
@@ -116,6 +119,7 @@ protected:
   }
 
   bool mIsFile;
+  bool mImmutable;
   nsString mContentType;
   nsString mName;
 
@@ -186,6 +190,7 @@ protected:
       mCacheToken(aOther->mCacheToken)
   {
     NS_ASSERTION(mFile, "must have file");
+    mImmutable = aOther->mImmutable;
   }
   virtual already_AddRefed<nsIDOMBlob>
   CreateSlice(PRUint64 aStart, PRUint64 aLength,
@@ -230,6 +235,7 @@ protected:
       mDataOwner(aOther->mDataOwner)
   {
     NS_ASSERTION(mDataOwner && mDataOwner->mData, "must have data");
+    mImmutable = aOther->mImmutable;
   }
   virtual already_AddRefed<nsIDOMBlob>
   CreateSlice(PRUint64 aStart, PRUint64 aLength,
diff --git a/content/base/src/nsDOMFile.cpp b/content/base/src/nsDOMFile.cpp
index ededcc26d2df..d4169f32d8fc 100644
--- a/content/base/src/nsDOMFile.cpp
+++ b/content/base/src/nsDOMFile.cpp
@@ -143,6 +143,7 @@ NS_INTERFACE_MAP_BEGIN(nsDOMFileBase)
   NS_INTERFACE_MAP_ENTRY(nsIDOMBlob)
   NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIDOMFile, mIsFile)
   NS_INTERFACE_MAP_ENTRY(nsIXHRSendable)
+  NS_INTERFACE_MAP_ENTRY(nsIMutable)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO_CONDITIONAL(File, mIsFile)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO_CONDITIONAL(Blob, !mIsFile)
 NS_INTERFACE_MAP_END
@@ -313,6 +314,35 @@ nsDOMFileBase::GetSendInfo(nsIInputStream** aBody,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDOMFileBase::GetMutable(PRBool* aMutable)
+{
+  *aMutable = !mImmutable;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDOMFileBase::SetMutable(PRBool aMutable)
+{
+  nsresult rv = NS_OK;
+
+  NS_ENSURE_ARG(!mImmutable || !aMutable);
+
+  if (!mImmutable && !aMutable) {
+    // Force the content type and size to be cached
+    nsString dummyString;
+    rv = this->GetType(dummyString);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    PRUint64 dummyInt;
+    rv = this->GetSize(&dummyInt);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  mImmutable = !aMutable;
+  return rv;
+}
+
 ////////////////////////////////////////////////////////////////////////////
 // nsDOMFileFile implementation
 
@@ -413,6 +443,9 @@ nsDOMFileFile::Initialize(nsISupports* aOwner,
 {
   nsresult rv;
 
+  NS_ASSERTION(!mImmutable, "Something went wrong ...");
+  NS_ENSURE_TRUE(!mImmutable, NS_ERROR_UNEXPECTED);
+
   if (!nsContentUtils::IsCallerChrome()) {
     return NS_ERROR_DOM_SECURITY_ERR; // Real short trip
   }