GDB support for Android in devtools' debugger.

mojo/devtools/common/android_gdb/remote_file_connection.py

Index: mojo/devtools/common/android_gdb/remote_file_connection.py
diff --git a/mojo/devtools/common/android_gdb/remote_file_connection.py b/mojo/devtools/common/android_gdb/remote_file_connection.py
new file mode 100644
index 0000000000000000000000000000000000000000..95247d59d3e4e13f5554bb24b3db434887eaae7d
--- /dev/null
+++ b/mojo/devtools/common/android_gdb/remote_file_connection.py
@@ -0,0 +1,66 @@
+# Copyright 2015 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.
+
+import socket
+import struct
+
+
+class RemoteFileConnectionException(Exception):
+  def __init__(self, *args, **kwargs):
+    Exception.__init__(self, *args, **kwargs)
+
+
+class RemoteFileConnection(object):
+  """Client for remote_file_reader server, allowing to read files on an
+  remote device.
+  """
+  def __init__(self, host, port):
+    self.host = host
+    self.port = port
+    self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    self._size_struct = struct.Struct("!i")

[ppi, 2015/07/09 13:12:39]

is "size_struct" the only private member? Should all of them get the
underscores?

[etiennej, 2015/07/15 07:13:20]

Done.

+
+  def connect(self):
+    self.socket.connect((self.host, self.port))
+
+  def close(self):

[ppi, 2015/07/09 13:12:39]

if this is a pair for "connect", let's call it "disconnect", or something else
that does not look like a pair for "open" below.

[qsr, 2015/07/09 13:54:18]

It has to be called close (and is in fact a pair for "open", as this is
implementing the file interface.

[qsr, 2015/07/09 14:06:16]

 Ok, I was mis-remembering, we do not ever close this, so it can be renamed
disconnect. What we should also do is add a __del__(self) method and call
disconnect on it.

[etiennej, 2015/07/15 07:13:20]

Done.

+    self.socket.close()
+
+  def open(self, filename):

[ppi, 2015/07/09 13:12:39]

When the file will be closed on the remote side? Is it ok to call open multiple
times for different files?

[qsr, 2015/07/09 13:54:18]

The file will be closed when you disconnect, or when you open a new one.

[etiennej, 2015/07/15 07:13:20]

Acknowledged.

+    self._send("O %s\n" % filename)
+    result = self._receive(1)
+    if result != 'O':
+      raise RemoteFileConnectionException("Unable to open file " + filename)
+
+  def seek(self, pos, mode=0):
+    self._send("S %d %d\n" % (pos, mode))
+    result = self._receive(1)
+    if result != 'O':
+      raise RemoteFileConnectionException("Unable to open file.")

[ppi, 2015/07/09 13:12:38]

Update the exception message here and below.

[etiennej, 2015/07/15 07:13:20]

Done.

+
+  def read(self, size=0):
+    assert size > 0
+    self._send("R %d\n" % size)
+    result = self._receive(1)
+    if result != 'O':
+      raise RemoteFileConnectionException("Unable to open file.")
+    read_size = self._size_struct.unpack(self._receive(4))[0]
+    return self._receive(read_size)
+
+  def _send(self, data):
+    while len(data) > 0:
+      sent = self.socket.send(data)
+      if sent == 0:
+        raise RemoteFileConnectionException("socket connection broken")

[ppi, 2015/07/09 13:12:39]

Capitalize and end with a period to match the others, here and below.

[etiennej, 2015/07/15 07:13:20]

Done.

+      data = data[sent:]
+
+  def _receive(self, length):
+    result = []
+    while length > 0:
+      chunk = self.socket.recv(length)
+      if chunk == '':
+        raise RemoteFileConnectionException("socket connection broken")
+      result.append(chunk)
+      length -= len(chunk)
+    return ''.join(result)