update bus.write

Signed-off-by: Mattias Andrée <maandree@operamail.com>

2 files changed, 17 insertions, 5 deletions

diff --git a/src/bus.py b/src/bus.py
index 4b3f9fd..7146e83 100644
--- a/src/bus.py
+++ b/src/bus.py
@@ -55,6 +55,12 @@ class Bus:
     Fail if interrupted
     '''
     
+    NOWAIT = 1
+    '''
+    Function shall fail with errno set to `EAGAIN`
+    if the it would block and this flag is used
+    '''
+    
     
     def __init__(self, pathname : str = None):
         '''
@@ -131,14 +137,16 @@ class Bus:
             self.bus = None
     
     
-    def write(self, message : str):
+    def write(self, message : str, flags : int = 0):
         '''
         Broadcast a message a bus
         
         @param  message:str  The message to write, may not be longer than 2047 bytes after UTF-8 encoding
+        @param  flags:int    `Bus.NOWAIT` if the function shall fail if there is another process attempting
+                             to broadcast on the bus
         '''
         from native_bus import bus_write_wrapped
-        if bus_write_wrapped(self.bus, message) == -1:
+        if bus_write_wrapped(self.bus, message, flags) == -1:
             raise self.__oserror()
     
     
diff --git a/src/native_bus.pyx b/src/native_bus.pyx
index de33e91..fdcf341 100644
--- a/src/native_bus.pyx
+++ b/src/native_bus.pyx
@@ -68,13 +68,15 @@ Close a bus
 @return       0 on success, -1 on error
 '''
 
-cdef extern int bus_write(long, const char *)
+cdef extern int bus_write(long, const char *, int)
 '''
 Broadcast a message a bus
 
 @param   bus      Bus information
 @param   message  The message to write, may not be longer than
                   `BUS_MEMORY_SIZE` including the NUL-termination
+@param   flags    `BUS_NOWAIT` fail if other process is attempting
+                  to write
 @return           0 on success, -1 on error
 '''
 
@@ -184,20 +186,22 @@ def bus_close_wrapped(bus : int) -> int:
     return bus_close(<long>bus)
 
 
-def bus_write_wrapped(bus : int, message : str) -> int:
+def bus_write_wrapped(bus : int, message : str, flags : int) -> int:
     '''
     Broadcast a message a bus
     
     @param   bus      Bus information
     @param   message  The message to write, may not be longer than
                       `BUS_MEMORY_SIZE` including the NUL-termination
+    @param   flags    `BUS_NOWAIT` fail if other process is attempting
+                      to write
     @return           0 on success, -1 on error
     '''
     cdef const char* cmessage
     cdef bytes bs
     bs = message.encode('utf-8') + bytes([0])
     cmessage = bs
-    return bus_write(<long>bus, cmessage)
+    return bus_write(<long>bus, cmessage, <int>flags)
 
 
 cdef int bus_callback_wrapper(const char *message, user_data):