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

android_webview/browser/input_stream.h

Index: android_webview/browser/input_stream.h
diff --git a/android_webview/browser/input_stream.h b/android_webview/browser/input_stream.h
new file mode 100644
index 0000000000000000000000000000000000000000..bd4898dc7449a64ceb225d8cef1fa981bad4b3df
--- /dev/null
+++ b/android_webview/browser/input_stream.h
@@ -0,0 +1,46 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ANDROID_WEBVIEW_BROWSER_INPUT_STREAM_H_
+#define ANDROID_WEBVIEW_BROWSER_INPUT_STREAM_H_
+
+#include "base/basictypes.h"
+
+namespace net {
+class IOBuffer;
+}
+
+namespace android_webview {
+
+class InputStream {

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

nit: comment it's an abstract wrapper, typically used to access the java class
of same name. and where you'd get an instance from?

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

Added a comment but will skip the 'where do you get an instance from' bit
because that will easily go stale (and it's pretty obvious from grepping that
there is a native input_stream_impl)

+ public:
+  virtual ~InputStream() {}
+
+  // Sets |bytes_available| to the number of bytes that can be read (or skipped
+  // over) from this input stream without blocking by the next caller of a
+  // method for this input stream.
+  // Returns true if completed successfully or false if an exception was
+  // thrown.
+  virtual bool BytesAvailable(int* bytes_available) const = 0;
+
+  // Skips over and discards |n| bytes of data from this input stream. Sets
+  // |bytes_skipped| to the number of of bytes skipped.
+  // Returns true if completed successfully or false if an exception was
+  // thrown.
+  virtual bool Skip(int64_t n, int64_t* bytes_skipped) = 0;
+
+  // Reads |length| bytes into |dest|. Sets |bytes_read| to the total number of
+  // bytes read into |dest| or -1 if there is no more data because the end of
+  // the stream was reached.
+  // |dest| must be at least |length| in size.
+  // Returns true if completed successfully or false if an exception was
+  // thrown.
+  virtual bool Read(net::IOBuffer* dest, int length, int* bytes_read) = 0;
+ protected:

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

nit: \n before

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

Done.

+  InputStream() {}
+};
+
+} // namespace android_webview
+
+#endif //  ANDROID_WEBVIEW_BROWSER_INPUT_STREAM_H_