Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block patches

# gpg: Signature made Tue Apr 28 15:35:05 2015 BST using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream: (76 commits)
  block: move I/O request processing to block/io.c
  block: extract bdrv_setup_io_funcs()
  block: add bdrv_set_dirty()/bdrv_reset_dirty() to block_int.h
  block: replace bdrv_states iteration with bdrv_next()
  vmdk: Widen before shifting 32 bit header field
  block/dmg: make it modular
  block/mirror: Always call block_job_sleep_ns()
  iotests: add incremental backup granularity tests
  iotests: add incremental backup failure recovery test
  iotests: add simple incremental backup case
  iotests: add QMP event waiting queue
  iotests: add invalid input incremental backup tests
  hbitmap: truncate tests
  block: Resize bitmaps on bdrv_truncate
  block: Ensure consistent bitmap function prototypes
  block: add BdrvDirtyBitmap documentation
  qmp: Add dirty bitmap status field in query-block
  qmp: add block-dirty-bitmap-clear
  qmp: Add support of "dirty-bitmap" sync mode for drive-backup
  block: Add bitmap successors
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 65 insertions, 30 deletions

diff --git a/scripts/qmp/qmp.py b/scripts/qmp/qmp.py
index 20b6ec7..1d38e3e 100644
--- a/scripts/qmp/qmp.py
+++ b/scripts/qmp/qmp.py
@@ -21,6 +21,9 @@ class QMPConnectError(QMPError):
 class QMPCapabilitiesError(QMPError):
     pass
 
+class QMPTimeoutError(QMPError):
+    pass
+
 class QEMUMonitorProtocol:
     def __init__(self, address, server=False):
         """
@@ -72,6 +75,44 @@ class QEMUMonitorProtocol:
 
     error = socket.error
 
+    def __get_events(self, wait=False):
+        """
+        Check for new events in the stream and cache them in __events.
+
+        @param wait (bool): block until an event is available.
+        @param wait (float): If wait is a float, treat it as a timeout value.
+
+        @raise QMPTimeoutError: If a timeout float is provided and the timeout
+                                period elapses.
+        @raise QMPConnectError: If wait is True but no events could be retrieved
+                                or if some other error occurred.
+        """
+
+        # Check for new events regardless and pull them into the cache:
+        self.__sock.setblocking(0)
+        try:
+            self.__json_read()
+        except socket.error, err:
+            if err[0] == errno.EAGAIN:
+                # No data available
+                pass
+        self.__sock.setblocking(1)
+
+        # Wait for new events, if needed.
+        # if wait is 0.0, this means "no wait" and is also implicitly false.
+        if not self.__events and wait:
+            if isinstance(wait, float):
+                self.__sock.settimeout(wait)
+            try:
+                ret = self.__json_read(only_event=True)
+            except socket.timeout:
+                raise QMPTimeoutError("Timeout waiting for event")
+            except:
+                raise QMPConnectError("Error while reading from socket")
+            if ret is None:
+                raise QMPConnectError("Error while reading from socket")
+            self.__sock.settimeout(None)
+
     def connect(self, negotiate=True):
         """
         Connect to the QMP Monitor and perform capabilities negotiation.
@@ -140,43 +181,37 @@ class QEMUMonitorProtocol:
         """
         Get and delete the first available QMP event.
 
-        @param wait: block until an event is available (bool)
+        @param wait (bool): block until an event is available.
+        @param wait (float): If wait is a float, treat it as a timeout value.
+
+        @raise QMPTimeoutError: If a timeout float is provided and the timeout
+                                period elapses.
+        @raise QMPConnectError: If wait is True but no events could be retrieved
+                                or if some other error occurred.
+
+        @return The first available QMP event, or None.
         """
-        self.__sock.setblocking(0)
-        try:
-            self.__json_read()
-        except socket.error, err:
-            if err[0] == errno.EAGAIN:
-                # No data available
-                pass
-        self.__sock.setblocking(1)
-        if not self.__events and wait:
-            self.__json_read(only_event=True)
-        event = self.__events[0]
-        del self.__events[0]
-        return event
+        self.__get_events(wait)
+
+        if self.__events:
+            return self.__events.pop(0)
+        return None
 
     def get_events(self, wait=False):
         """
         Get a list of available QMP events.
 
-        @param wait: block until an event is available (bool)
-        """
-        self.__sock.setblocking(0)
-        try:
-            self.__json_read()
-        except socket.error, err:
-            if err[0] == errno.EAGAIN:
-                # No data available
-                pass
-        self.__sock.setblocking(1)
-        if not self.__events and wait:
-            ret = self.__json_read(only_event=True)
-            if ret == None:
-                # We are in blocking mode, if don't get anything, something
-                # went wrong
-                raise QMPConnectError("Error while reading from socket")
+        @param wait (bool): block until an event is available.
+        @param wait (float): If wait is a float, treat it as a timeout value.
 
+        @raise QMPTimeoutError: If a timeout float is provided and the timeout
+                                period elapses.
+        @raise QMPConnectError: If wait is True but no events could be retrieved
+                                or if some other error occurred.
+
+        @return The list of available QMP events.
+        """
+        self.__get_events(wait)
         return self.__events
 
     def clear_events(self):