[android_webview] Don't block the IO thread when reading from an InputStream.

android_webview/browser/net/android_stream_reader_url_request_job.h

Index: android_webview/browser/net/android_stream_reader_url_request_job.h
diff --git a/android_webview/native/android_stream_reader_url_request_job.h b/android_webview/browser/net/android_stream_reader_url_request_job.h
similarity index 71%
rename from android_webview/native/android_stream_reader_url_request_job.h
rename to android_webview/browser/net/android_stream_reader_url_request_job.h
index e29acd86e90045dfcb2265d78d2d80fc217e9c53..725ca259bf8e459e34b3f78062a33fc99ae67957 100644
--- a/android_webview/native/android_stream_reader_url_request_job.h
+++ b/android_webview/browser/net/android_stream_reader_url_request_job.h
@@ -6,12 +6,22 @@
 #define ANDROID_WEBVIEW_NATIVE_ANDROID_STREAM_READER_URL_REQUEST_JOB_H_
 
 #include "base/android/scoped_java_ref.h"
+#include "base/location.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "net/http/http_byte_range.h"
 #include "net/url_request/url_request_job.h"
 
+namespace android_webview {
+class InputStream;
+class InputStreamReader;
+}
+
+namespace base {
+class TaskRunner;
+}
+
 namespace net {
 class URLRequest;
 }
@@ -25,20 +35,20 @@ class AndroidStreamReaderURLRequestJob : public net::URLRequestJob {
    */
   class Delegate {
    public:
-    virtual base::android::ScopedJavaLocalRef<jobject> OpenInputStream(
+    virtual scoped_ptr<android_webview::InputStream> OpenInputStream(
         JNIEnv* env,
         net::URLRequest* request) = 0;
 
     virtual bool GetMimeType(
         JNIEnv* env,
         net::URLRequest* request,
-        jobject stream,
+        const android_webview::InputStream& stream,
         std::string* mime_type) = 0;
 
     virtual bool GetCharset(
         JNIEnv* env,
         net::URLRequest* request,
-        jobject stream,
+        const android_webview::InputStream& stream,
         std::string* charset) = 0;
 
     virtual ~Delegate() {}
@@ -51,6 +61,7 @@ class AndroidStreamReaderURLRequestJob : public net::URLRequestJob {
 
   // URLRequestJob:
   virtual void Start() OVERRIDE;
+  virtual void Kill() OVERRIDE;
   virtual bool ReadRawData(net::IOBuffer* buf,
                            int buf_size,
                            int* bytes_read) OVERRIDE;
@@ -62,24 +73,27 @@ class AndroidStreamReaderURLRequestJob : public net::URLRequestJob {
  protected:
   virtual ~AndroidStreamReaderURLRequestJob();
 
- private:
-  // Verify the requested range against the stream size.
-  bool VerifyRequestedRange(JNIEnv* env);
+  // Gets the TaskRunner for the worker thread.
+  // Useful to override in tests.
+  virtual base::TaskRunner* GetWorkerThreadRunner();
 
-  // Skip to the first byte of the requested read range.
-  bool SkipToRequestedRange(JNIEnv* env);
+  // Creates an InputStreamReader instance.
+  virtual android_webview::InputStreamReader*

[joth, 2012/11/20 20:46:35]

comment ownership is not returned. (I come from a world where CreateXxx always
returned ownership. maybe use a different method name if you think of one).

[mkosiba (inactive), 2012/11/21 15:19:47]

umm.. why do you think ownership is not returned? this is a regular factory
method (in the sense that the caller must take ownership of the result), the
fact that the caller is the same class as the method is implemented shouldn't
matter.

[joth, 2012/11/21 21:11:00]

I've become too used to see scoped_ptr to indicate ownership transfer; forgot
all about refcounted. (also the scoped members below confused me into thinking
ownership was retained)

- could comment why this is virtual; seems it could be static. (or indeed, why
it exists at all)
- could return scoped_refptr<> to be super clear. (until recently it was
unadvised to do that due to the implicit conversion to T*, but now that's going 
I think it makes a lot of sense to return the full owning type and makes it
nicely consistent with contemporary scoped_ptr usage patterns.)

+      CreateStreamReader(android_webview::InputStream* stream);
 
+ private:
   void StartAsync();
 
+  void OnReaderSeekCompleted(int content_size);
+  void OnReaderReadCompleted(int bytes_read);
+
   net::HttpByteRange byte_range_;
   scoped_ptr<Delegate> delegate_;
-  base::android::ScopedJavaGlobalRef<jobject> stream_;
-  base::android::ScopedJavaGlobalRef<jbyteArray> buffer_;
+  scoped_refptr<android_webview::InputStreamReader> input_stream_reader_;
+  scoped_ptr<android_webview::InputStream> stream_;
   base::WeakPtrFactory<AndroidStreamReaderURLRequestJob> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AndroidStreamReaderURLRequestJob);
 };
 
-bool RegisterAndroidStreamReaderUrlRequestJob(JNIEnv* env);
-
 #endif  // ANDROID_WEBVIEW_NATIVE_ANDROID_STREAM_READER_URL_REQUEST_JOB_H_