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

1 files changed, 169 insertions, 0 deletions

diff --git a/src/bus.py b/src/bus.py
new file mode 100644
index 0000000..267a435
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+++ b/src/bus.py
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+# -*- python -*-
+'''
+MIT/X Consortium License
+
+Copyright © 2015  Mattias Andrée <maandree@member.fsf.org>
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+'''
+
+
+class Bus:
+    '''
+    Message broadcasting interprocess communication
+    '''
+    
+    
+    RDONLY = 1
+    '''
+    Open the bus for reading only
+    '''
+
+    WRONLY = 0
+    '''
+    Open the bus for writing only
+    '''
+    
+    RDWR = 0
+    '''
+    Open the bus for both reading and writing only
+    '''
+    
+    EXCL = 2
+    '''
+    Fail to create bus if its file already exists
+    '''
+    
+    INTR = 4
+    '''
+    Fail if interrupted
+    '''
+    
+    
+    def __init__(self, pathname : str = None):
+        '''
+        Constructor
+        
+        @param  pathname:str  The pathname of the bus, `None` if `create` should select a random pathname
+        '''
+        self.pathname = pathname
+        self.bus = None
+    
+    
+    def create(self, flags : int = 0) -> str:
+        '''
+        Create the bus
+        
+        @param   flags:or_flag  `Bus.EXCL` (if the pathname is not `None`) to fail if the file
+                                already exists, otherwise if the file exists, nothing will happen;
+                                `Bus.INTR` to fail if interrupted
+        @return  :str           The pathname of the bus
+        '''
+        from native_bus import bus_create_wrapped
+        self.pathname = bus_create_wrapped(self.pathname, flags)
+        if self.pathname is None:
+            raise self.__oserror()
+        return self.pathname
+    
+    
+    def unlink(self):
+        '''
+        Remove the bus
+        '''
+        from native_bus import bus_unlink_wrapped
+        if bus_unlink_wrapped(self.pathname) == -1:
+            raise self.__oserror()
+    
+    
+    def open(self, flags : int = 0):
+        '''
+        Open an existing bus
+        
+        @param  flags:int  `Bus.RDONLY`, `Bus.WRONLY` or `Bus.RDWR`, the value must not be negative
+        '''
+        from native_bus import bus_close_wrapped, bus_allocate, bus_open_wrapped
+        if self.bus is not None:
+            if bus_close_wrapped(self.bus) == -1:
+                raise self.__oserror()
+        else:
+            self.bus = bus_allocate()
+            if self.bus == 0:
+                raise self.__oserror()
+        if bus_open_wrapped(self.bus, self.pathname, flags) == -1:
+            raise self.__oserror()
+    
+    
+    def close(self):
+        '''
+        Close the bus
+        '''
+        from native_bus import bus_close_wrapped, bus_deallocate
+        if self.bus is not None:
+            if bus_close_wrapped(self.bus) == -1:
+                raise self.__oserror()
+            bus_deallocate(self.bus)
+            self.bus = None
+    
+    
+    def write(self, message : str):
+        '''
+        Broadcast a message a bus
+        
+        @param  message:str  The message to write, may not be longer than 2047 bytes after UTF-8 encoding
+        '''
+        from native_bus import bus_write
+        if bus_write(self.bus, message) == -1:
+            raise self.__oserror()
+    
+    
+    def read(self, callback : callable, user_data = None):
+        '''
+        Listen (in a loop, forever) for new message on a bus
+        
+        @param   bus       Bus information
+        @param   callback  Function to call when a message is received, the
+                           input parameters will be the read message and
+                           `user_data` from the function's [Bus.read] parameter
+                           with the same name. The message must have been parsed
+                           or copied when `callback` returns as it may be over
+                           overridden after that time. `callback` should
+                           return either of the the values:
+                             0:  stop listening
+                             1:  continue listening
+                             -1:  an error has occurred
+        @param  user_data  See description of `callback`
+        '''
+        from native_bus import bus_read
+        if bus_read(self.bus, callback, user_data) == -1:
+            raise self.__oserror()
+    
+    
+    def __oserror(self):
+        '''
+        Create an OSError
+        
+        @return  :OSError  The OS error
+        '''
+        import os, ctypes
+        err = ctypes.get_errno()
+        err = OSError(err, os.strerror(err))
+        if err.errno == os.errno.ENOENT:
+            err.filename = self.pathname
+        return err
+