Implementing timeout support for XHR

Source/core/loader/DocumentThreadableLoader.cpp

Index: Source/core/loader/DocumentThreadableLoader.cpp
diff --git a/Source/core/loader/DocumentThreadableLoader.cpp b/Source/core/loader/DocumentThreadableLoader.cpp
index 88dde159b88a9d7bf8b16b9c89951158f72552f7..88b0b4ace20390025b4227aedb27cb052bfc5384 100644
--- a/Source/core/loader/DocumentThreadableLoader.cpp
+++ b/Source/core/loader/DocumentThreadableLoader.cpp
@@ -78,6 +78,7 @@ DocumentThreadableLoader::DocumentThreadableLoader(Document* document, Threadabl
     , m_sameOriginRequest(securityOrigin()->canRequest(request.url()))
     , m_simpleRequest(true)
     , m_async(blockingBehavior == LoadAsynchronously)
+    , m_timeoutTimer(this, &DocumentThreadableLoader::timedOut)
 {
     ASSERT(document);
     ASSERT(client);
@@ -145,14 +146,22 @@ DocumentThreadableLoader::~DocumentThreadableLoader()
 
 void DocumentThreadableLoader::cancel()
 {
+    cancel(ResourceError());
+}
+
+void DocumentThreadableLoader::cancel(const ResourceError& error)
+{
     RefPtr<DocumentThreadableLoader> protect(this);
 
     // Cancel can re-enter and m_resource might be null here as a result.
     if (m_client && m_resource) {
-        // FIXME: This error is sent to the client in didFail(), so it should not be an internal one. Use FrameLoaderClient::cancelledError() instead.
-        ResourceError error(errorDomainWebKitInternal, 0, m_resource->url().string(), "Load cancelled");
-        error.setIsCancellation(true);
-        didFail(m_resource->identifier(), error);
+        ResourceError errorForCallback = error;
+        if (error.isNull()) {

[abarth-chromium, 2013/05/17 05:10:40]

I probably would have written errorForCallback.isNull since that's the object
we're working with in this stanza.

+            // FIXME: This error is sent to the client in didFail(), so it should not be an internal one. Use FrameLoaderClient::cancelledError() instead.
+            errorForCallback = ResourceError(errorDomainWebKitInternal, 0, m_resource->url().string(), "Load cancelled");
+            errorForCallback.setIsCancellation(true);
+        }
+        didFail(m_resource->identifier(), errorForCallback);
     }
     clearResource();
     m_client = 0;
@@ -323,6 +332,8 @@ void DocumentThreadableLoader::notifyFinished(CachedResource* resource)
 {
     ASSERT(m_client);
     ASSERT_UNUSED(resource, resource == m_resource);
+
+    m_timeoutTimer.stop();
         
     if (m_resource->errorOccurred())
         didFail(m_resource->identifier(), m_resource->resourceError());
@@ -371,6 +382,20 @@ void DocumentThreadableLoader::preflightFailure(unsigned long identifier, const
     m_client->didFailAccessControlCheck(error);
 }
 
+void DocumentThreadableLoader::timedOut(Timer<DocumentThreadableLoader>* timer)
+{
+    ASSERT_UNUSED(timer, timer == &m_timeoutTimer);
+
+    // Using values from net/base/net_error_list.h ERR_TIMED_OUT,
+    // Same as existing FIXME above - this error should be coming from FrameLoaderClient to be identifiable.
+    static const int timeoutError = -7;
+    static const char* const errorDomain = "net";
+    ResourceError error(errorDomain, timeoutError, m_resource->url(), String());

[abarth-chromium, 2013/05/17 05:10:40]

I would probably just inline the string constant into the one place it's used. 
The numeric constant for timeoutError is helpful though.

+    error.setIsTimeout(true);
+    cancel(error);
+}
+
+
 void DocumentThreadableLoader::loadRequest(const ResourceRequest& request, SecurityCheckPolicy securityCheck)
 {
     // Any credential should have been removed from the cross-site requests.
@@ -390,6 +415,9 @@ void DocumentThreadableLoader::loadRequest(const ResourceRequest& request, Secur
             options.dataBufferingPolicy = BufferData;
         }
 
+        if (m_options.timeoutMilliseconds > 0)
+            m_timeoutTimer.startOneShot(m_options.timeoutMilliseconds / 1000.0);
+
         CachedResourceRequest newRequest(request, options);
         newRequest.setInitiator(m_options.initiator);
         ASSERT(!m_resource);