Re: [libvirt] Re: [PATCH 01/12] Domain Events - Public API
On Tue, Oct 21, 2008 at 03:11:08PM -0400, Ben Guthro wrote:
[PATCH 01/12] Domain Events - Public API
This patch does the following:
-implements the Event register/deregister code
-Adds some callback lists, and queue functions used by drivers
-Move EventImpl definitions into the public
+
+/**
+ * virEventHandleType:
+ *
+ * a virEventHandleType is used similar to POLLxxx FD events, but is specific
+ * to libvirt. A client app must translate to, and from POLL events when using
+ * this construct.
+ */
+typedef enum {
+ VIR_EVENT_HANDLE_READABLE = (1 << 0),
+ VIR_EVENT_HANDLE_WRITABLE = (1 << 1),
+ VIR_EVENT_HANDLE_ERROR = (1 << 2),
+ VIR_EVENT_HANDLE_HANGUP = (1 << 3),
+} virEventHandleType;
+
+/**
+ * virEventHandleCallback: callback for receiving file handle events
+ *
+ * @fd: file handle on which the event occurred
+ * @events: bitset of events from virEventHandleType constants
+ * @opaque: user data registered with handle
+ */
+typedef void (*virEventHandleCallback)(int fd, virEventHandleType events,
+ void *opaque);
We avoid using explicit enum types in any public API because they are
not ABI safe in terms of their size. In any case, the 'events' parameter
is atually a bit-mask of zero or more of the virEventHandleType constants,
so the use of the enum isn't technically correct.
+
+/**
+ * virEventAddHandleFunc:
+ * @fd: file descriptor to listen on
+ * @event: events on which to fire the callback
+ * @cb: the callback to be called
+ * @opaque: user data to pass to the callback
+ *
+ * Part of the EventImpl, this callback Adds a file handle callback to
+ * listen for specific events
+ */
+typedef int (*virEventAddHandleFunc)(int fd, virEventHandleType event,
+ virEventHandleCallback cb, void *opaque);
Here too we should just use 'int events' as a bitmask
+
+/**
+ * virEventUpdateHandleFunc:
+ * @fd: file descriptor to modify
+ * @event: new events to listen on
+ *
+ * Part of the EventImpl, this user-provided callback is notified when
+ * events to listen on change
+ */
+typedef void (*virEventUpdateHandleFunc)(int fd, virEventHandleType event);
Same 'int events' here too.
+
+
+int
+__virEventHandleTypeToPollEvent(virEventHandleType events)
+{
+ int ret = 0;
+ if(events & VIR_EVENT_HANDLE_READABLE)
+ ret |= POLLIN;
+ if(events & VIR_EVENT_HANDLE_WRITABLE)
+ ret |= POLLOUT;
+ if(events & VIR_EVENT_HANDLE_ERROR)
+ ret |= POLLERR;
+ if(events & VIR_EVENT_HANDLE_HANGUP)
+ ret |= POLLHUP;
+ return ret;
+}
+
+virEventHandleType
+__virPollEventToEventHandleType(int events)
+{
+ virEventHandleType ret = 0;
+ if(events & POLLIN)
+ ret |= VIR_EVENT_HANDLE_READABLE;
+ if(events & POLLOUT)
+ ret |= VIR_EVENT_HANDLE_WRITABLE;
+ if(events & POLLERR)
+ ret |= VIR_EVENT_HANDLE_ERROR;
+ if(events & POLLHUP)
+ ret |= VIR_EVENT_HANDLE_HANGUP;
+ return ret;
+}
Since these two functions are only used by the libvirtd daemon at
this point, I think its better to just put them in qemud/event.c.
This will avoid need to add conditionals here to disable their
build on Mingw/Windows.
diff --git a/src/libvirt_sym.version b/src/libvirt_sym.version
index 3cc4505..0297c9c 100644
--- a/src/libvirt_sym.version
+++ b/src/libvirt_sym.version
@@ -147,6 +147,10 @@
virStorageVolGetXMLDesc;
virStorageVolGetPath;
+ virEventRegisterImpl;
+ virConnectDomainEventRegister;
+ virConnectDomainEventDeregister;
+
/* Symbols with __ are private only
for use by the libvirtd daemon.
They are not part of stable ABI
@@ -167,8 +171,6 @@
__virGetStoragePool;
__virGetStorageVol;
- __virEventRegisterImpl;
-
__virStateInitialize;
__virStateCleanup;
__virStateReload;
@@ -198,5 +200,7 @@
__virReallocN;
__virFree;
+ __virEventHandleTypeToPollEvent;
+ __virPollEventToEventHandleType;
These will also be unnecccessary if we put them in qemud/event.c
Daniel
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