[Android] Fix handling of asset files loading.

chrome/browser/android/android_protocol_adapter.cc

Index: chrome/browser/android/android_protocol_adapter.cc
diff --git a/chrome/browser/android/android_protocol_adapter.cc b/chrome/browser/android/android_protocol_adapter.cc
index aea709200073d5f5cd0a09c3e0502cf58347cf01..6b3f775769ab7b7a5069537644cce02ed8fb1c8e 100644
--- a/chrome/browser/android/android_protocol_adapter.cc
+++ b/chrome/browser/android/android_protocol_adapter.cc
@@ -19,8 +19,9 @@
 #include "net/base/net_errors.h"
 #include "net/base/net_util.h"
 #include "net/http/http_util.h"
-#include "net/url_request/url_request_error_job.h"
-#include "net/url_request/url_request_file_job.h"
+#include "net/url_request/url_request_context.h"
+#include "net/url_request/url_request_context_getter.h"
+#include "net/url_request/url_request_job_factory.h"
 #include "net/url_request/url_request_job_manager.h"
 
 using base::android::AttachCurrentThread;
@@ -64,6 +65,26 @@ class AndroidStreamReaderURLRequestJobDelegateImpl
   virtual ~AndroidStreamReaderURLRequestJobDelegateImpl();
 };
 
+class AssetFileProtocolInterceptor :
+      public net::URLRequestJobFactory::Interceptor {
+ public:
+  AssetFileProtocolInterceptor();
+  virtual ~AssetFileProtocolInterceptor() OVERRIDE;
+  virtual net::URLRequestJob* MaybeIntercept(
+      net::URLRequest* request,
+      net::NetworkDelegate* network_delegate) const OVERRIDE;
+  virtual net::URLRequestJob* MaybeInterceptRedirect(
+      const GURL& location,
+      net::URLRequest* request,
+      net::NetworkDelegate* network_delegate) const OVERRIDE;
+  virtual net::URLRequestJob* MaybeInterceptResponse(
+      net::URLRequest* request,
+      net::NetworkDelegate* network_delegate) const OVERRIDE;
+
+ private:
+  const std::string kAssetPrefix;
+  const std::string kResourcePrefix;
+};
 
 } // namespace
 
@@ -77,24 +98,7 @@ net::URLRequestJob* AndroidProtocolAdapter::Factory(
     net::URLRequest* request,
     net::NetworkDelegate* network_delegate,
     const std::string& scheme) {
-  DCHECK(scheme == chrome::kFileScheme ||
-         scheme == chrome::kContentScheme);
-  JNIEnv* env = AttachCurrentThread();
-  DCHECK(env);
-  // If this is a file:// URL we cannot handle, fall back to the default
-  // handler.
-  const std::string& url = request->url().spec();
-  std::string assetPrefix = std::string(chrome::kFileScheme) + "://" +
-      chrome::kAndroidAssetPath;
-  std::string resourcePrefix = std::string(chrome::kFileScheme) + "://" +
-      chrome::kAndroidResourcePath;
-
-  if (scheme == chrome::kFileScheme &&
-      !StartsWithASCII(url, assetPrefix, /*case_sensitive=*/ true) &&
-      !StartsWithASCII(url, resourcePrefix,  /*case_sensitive=*/ true)) {
-    return net::URLRequestFileJob::Factory(request, network_delegate, scheme);
-  }
-
+  DCHECK(scheme == chrome::kContentScheme);
   return new AndroidStreamReaderURLRequestJob(
       request,
       network_delegate,
@@ -102,25 +106,40 @@ net::URLRequestJob* AndroidProtocolAdapter::Factory(
           new AndroidStreamReaderURLRequestJobDelegateImpl()));
 }
 
+static void AddFileSchemeInterceptorOnIOThread(
+    net::URLRequestContextGetter* context_getter) {
+  // The job factory takes ownership of the interceptor.
+  const_cast<net::URLRequestJobFactory*>(
+      context_getter->GetURLRequestContext()->job_factory())->AddInterceptor(
+          new AssetFileProtocolInterceptor());
+}
+
 // static
-bool AndroidProtocolAdapter::RegisterProtocols(JNIEnv* env) {
+void AndroidProtocolAdapter::RegisterProtocols(
+    JNIEnv* env, net::URLRequestContextGetter* context_getter) {
   DCHECK(env);
+  if (!InitJNIBindings(env)) {
+    // Must not fail.
+    NOTREACHED();
+  }
 
-  if (!InitJNIBindings(env))
-    return false;
-
-  // Register content:// and file://. Note that even though a scheme is
+  // Register content://. Note that even though a scheme is
   // registered here, it cannot be used by child processes until access to it is
   // granted via ChildProcessSecurityPolicy::GrantScheme(). This is done in
   // RenderViewHost.
+  //
+  // TODO(mnaganov): Convert into a ProtocolHandler.
   net::URLRequestJobManager* job_manager =
       net::URLRequestJobManager::GetInstance();
   job_manager->RegisterProtocolFactory(chrome::kContentScheme,
       &AndroidProtocolAdapter::Factory);
-  job_manager->RegisterProtocolFactory(
-      chrome::kFileScheme, &AndroidProtocolAdapter::Factory);
 
-  return true;
+  // Register a file: scheme interceptor for application assets.
+  context_getter->GetNetworkTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AddFileSchemeInterceptorOnIOThread,
+                 make_scoped_refptr(context_getter)));
+  // TODO(mnaganov): Add an interceptor for the incognito profile?
 }
 
 // Set a context object to be used for resolving resource queries. This can
@@ -225,3 +244,45 @@ bool AndroidStreamReaderURLRequestJobDelegateImpl::GetCharset(
   // TODO: We should probably be getting this from the managed side.
   return false;
 }
+
+AssetFileProtocolInterceptor::AssetFileProtocolInterceptor() :
+    kAssetPrefix(std::string(chrome::kFileScheme) +

[joth, 2012/08/29 19:49:33]

nit: initializer colon should be on this line

[mnaganov (inactive), 2012/08/30 09:24:38]

Done.

+                 std::string(content::kStandardSchemeSeparator) +
+                 chrome::kAndroidAssetPath),
+    kResourcePrefix(std::string(chrome::kFileScheme) +

[joth, 2012/08/29 19:49:33]

nit: I think technically kConst is only for things constants that are statically
defined at compile time.

On balance I think these may as well be done that way too (i.e.: static const
char[] kFoo = "file://android_asset"). while it means we 'duplicate' parts of
the string literals on the flip side it makes it much easier to see (and verify)
exactly what those constants contains, and in reality these aren't going to
change a whole lot as they're in the public API spec.

[mnaganov (inactive), 2012/08/30 09:24:38]

Agree. Changed to asset_prefix_ and resource_prefix_.
 
Well, URI scheme names also doesn't change, but we anyway have constants for
them. One reason for using constants is that if you mistype the name of the
constant, you'll get a compiler error. For clarity, I've added comments for
these constants with their intended values.

[joth, 2012/08/30 18:10:40]

Ah I wasn't meaning to suggest removing constants, just change them to be true
compile-time constants, e.g.:

namespace {
const char[] kAndroidAssetPrefix = "file://android_asset";
...
}

+                    std::string(content::kStandardSchemeSeparator) +
+                    chrome::kAndroidResourcePath) {
+}
+
+AssetFileProtocolInterceptor::~AssetFileProtocolInterceptor() {
+}
+
+net::URLRequestJob* AssetFileProtocolInterceptor::MaybeIntercept(
+    net::URLRequest* request, net::NetworkDelegate* network_delegate) const {
+  if (!request->url().SchemeIsFile()) return NULL;
+
+  const std::string& url = request->url().spec();
+  if (!StartsWithASCII(url, kAssetPrefix, /*case_sensitive=*/ true) &&
+      !StartsWithASCII(url, kResourcePrefix,  /*case_sensitive=*/ true)) {
+    return NULL;
+  }
+
+  return new AndroidStreamReaderURLRequestJob(
+      request,
+      network_delegate,
+      scoped_ptr<AndroidStreamReaderURLRequestJob::Delegate>(
+          new AndroidStreamReaderURLRequestJobDelegateImpl()));
+}
+
+net::URLRequestJob* AssetFileProtocolInterceptor::MaybeInterceptRedirect(
+    const GURL& location,
+    net::URLRequest* request,
+    net::NetworkDelegate* network_delegate) const {
+  return NULL;
+}
+
+net::URLRequestJob* AssetFileProtocolInterceptor::MaybeInterceptResponse(
+    net::URLRequest* request,
+    net::NetworkDelegate* network_delegate) const {
+  return NULL;
+}