From 2f16fd55a408b31e1145b1d4cf4683cd3294510e Mon Sep 17 00:00:00 2001
From: Paul Adenot <paul@paul.cx>
Date: Tue, 26 Jun 2012 10:33:00 -0700
Subject: [PATCH] Bug 767087 - Add a flag to force content sniffing when we get
 served application/octet-stream. r=jduell

---
 netwerk/base/public/nsIChannel.idl      |  8 ++++++++
 netwerk/base/src/nsBaseChannel.cpp      | 12 +++++++++---
 netwerk/protocol/http/nsHttpChannel.cpp |  5 ++++-
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/netwerk/base/public/nsIChannel.idl b/netwerk/base/public/nsIChannel.idl
index 9947e597778..78e86b8d721 100644
--- a/netwerk/base/public/nsIChannel.idl
+++ b/netwerk/base/public/nsIChannel.idl
@@ -241,6 +241,14 @@ interface nsIChannel : nsIRequest
      */
     const unsigned long LOAD_CLASSIFY_URI = 1 << 22;
 
+    /**
+     * If this flag is set and a server's response is Content-Type
+     * application/octet-steam, the server's Content-Type will be ignored and
+     * the channel content will be sniffed as though no Content-Type had been
+     * passed.
+     */
+    const unsigned long LOAD_TREAT_APPLICATION_OCTET_STREAM_AS_UNKNOWN = 1 << 23;
+
     /**
      * Access to the type implied or stated by the Content-Disposition header
      * if available and if applicable. This allows determining inline versus
diff --git a/netwerk/base/src/nsBaseChannel.cpp b/netwerk/base/src/nsBaseChannel.cpp
index 7a06a3ab0cc..6bd29ba0138 100644
--- a/netwerk/base/src/nsBaseChannel.cpp
+++ b/netwerk/base/src/nsBaseChannel.cpp
@@ -682,9 +682,15 @@ CallUnknownTypeSniffer(void *aClosure, const PRUint8 *aData, PRUint32 aCount)
 NS_IMETHODIMP
 nsBaseChannel::OnStartRequest(nsIRequest *request, nsISupports *ctxt)
 {
-  // If our content type is unknown, then use the content type sniffer.  If the
-  // sniffer is not available for some reason, then we just keep going as-is.
-  if (NS_SUCCEEDED(mStatus) && mContentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE)) {
+  // If our content type is unknown or if the content type is
+  // application/octet-stream and the caller requested it, use the content type
+  // sniffer. If the sniffer is not available for some reason, then we just keep
+  // going as-is.
+  bool shouldSniff = mContentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE) ||
+            ((mLoadFlags & LOAD_TREAT_APPLICATION_OCTET_STREAM_AS_UNKNOWN) &&
+            mContentType.EqualsLiteral(APPLICATION_OCTET_STREAM));
+
+  if (NS_SUCCEEDED(mStatus) && shouldSniff) {
     mPump->PeekStream(CallUnknownTypeSniffer, static_cast<nsIChannel*>(this));
   }
 
diff --git a/netwerk/protocol/http/nsHttpChannel.cpp b/netwerk/protocol/http/nsHttpChannel.cpp
index 116d66d36c4..ea8db6a9644 100644
--- a/netwerk/protocol/http/nsHttpChannel.cpp
+++ b/netwerk/protocol/http/nsHttpChannel.cpp
@@ -881,8 +881,11 @@ nsresult
 nsHttpChannel::CallOnStartRequest()
 {
     mTracingEnabled = false;
+    bool shouldSniff = mResponseHead && (mResponseHead->ContentType().IsEmpty() ||
+        ((mResponseHead->ContentType().EqualsLiteral(APPLICATION_OCTET_STREAM) &&
+        (mLoadFlags & LOAD_TREAT_APPLICATION_OCTET_STREAM_AS_UNKNOWN))));
 
-    if (mResponseHead && mResponseHead->ContentType().IsEmpty()) {
+    if (shouldSniff) {
         NS_ASSERTION(mConnectionInfo, "Should have connection info here");
         if (!mContentTypeHint.IsEmpty())
             mResponseHead->SetContentType(mContentTypeHint);