Separate out the display of 'requested' and 'applied' breakpoints

This is a mess, with a load of duplication, but it's a step. When you
request a breakpoint, we add one (in state ENABLED). You can then toggle
it again to change to DISABLED. And once more to delete it.

Once we start the debug server, that all changes and we just start
sending the breakpoints directly to the server and updating based on the
responses. This is far from ideal and somewhat jarring, but this
approach allows me to play around with ideas about what the user
experience should look like.

python3/vimspector/debug_session.py

@@ -27,6 +27,8 @@ from vimspector import ( code,
                          utils,
                          variables )
 
+SIGN_ID_OFFSET = 10005000
+
 
 class DebugSession( object ):
   def __init__( self ):
@@ -41,16 +43,30 @@ class DebugSession( object ):
 
     self._currentThread = None
     self._currentFrame = None
+    self._next_sign_id = SIGN_ID_OFFSET
 
+    # TODO: Move to code view and consolidate into user-requested-breakpoints,
+    # and actual breakpoints ?
     self._breakpoints = defaultdict( dict )
     self._configuration = None
 
+    vim.command( 'sign define vimspectorBP text=o texthl=Error' )
+    vim.command( 'sign define vimspectorBPDisabled text=! texthl=Warning' )
+
   def ToggleBreakpoint( self ):
+    # TODO: Move this to the code view. Problem is that CodeView doesn't exist
+    # until we have initialised.
     line, column = vim.current.window.cursor
     file_name = vim.current.buffer.name
 
     if line in self._breakpoints[ file_name ]:
-      del self._breakpoints[ file_name ][ line ]
+      bp = self._breakpoints[ file_name ][ line ]
+      if bp[ 'state' ] == 'ENABLED':
+        bp[ 'state' ] = 'DISABLED'
+      else:
+        if 'sign_id' in bp:
+          vim.command( 'sign unplace {0}'.format( bp[ 'sign_id' ] ) )
+        del self._breakpoints[ file_name ][ line ]
     else:
       self._breakpoints[ file_name ][ line ] = {
         'state': 'ENABLED',
@@ -59,6 +75,12 @@ class DebugSession( object ):
         # 'logMessage': ...
       }
 
+    if self._connection:
+      self._SendBreakpoints()
+    else:
+      self._ShowBreakpoints()
+
+
   def Start( self, configuration = None ):
     launch_config_file = utils.PathToConfigFile( '.vimspector.json' )
 
@@ -221,25 +243,42 @@ class DebugSession( object ):
   def OnEvent_initialized( self, message ):
     self._codeView.ClearBreakpoints()
 
+    self._SendBreakpoints()
+
+  def _SendBreakpoints( self ):
     for file_name, line_breakpoints in self._breakpoints.items():
-      breakpoints = [ { 'line': line } for line in line_breakpoints.keys() ]
+      breakpoints = []
+      lines = []
+      for line, bp in line_breakpoints.items():
+        if bp[ 'state' ] != 'ENABLED':
+          continue
+
+        if 'sign_id' in bp:
+          vim.command( 'sign unplace {0}'.format( bp[ 'sign_id' ] ) )
+          del bp[ 'sign_id' ]
+
+        breakpoints.append( { 'line': line } )
+        lines.append( line )
+
       source = {
         'name': os.path.basename( file_name ),
         'path': file_name,
       }
+
       self._connection.DoRequest(
         functools.partial( self._UpdateBreakpoints, source ),
         {
           'command': 'setBreakpoints',
           'arguments': {
             'source': source,
-            'breakpoints': breakpoints,
-            'lines': [ line for line in line_breakpoints.keys() ],
-            'sourceModified': False,
+            'breakpoints': breakpoints
           },
+          'lines':  lines,
+          'sourceModified': False, # TODO: We can actually check this
         }
       )
 
+    # TODO: Remove this!
     self._connection.DoRequest(
       functools.partial( self._UpdateBreakpoints, None ),
       {
@@ -256,6 +295,23 @@ class DebugSession( object ):
       'command': 'configurationDone',
     } )
 
+  def _ShowBreakpoints( self ):
+    for file_name, line_breakpoints in self._breakpoints.items():
+      for line, bp in line_breakpoints.items():
+        if 'sign_id' in bp:
+          vim.command( 'sign unplace {0}'.format( bp[ 'sign_id' ] ) )
+        else:
+          bp[ 'sign_id' ] = self._next_sign_id
+          self._next_sign_id += 1
+
+        vim.command(
+          'sign place {0} line={1} name={2} file={3}'.format(
+            bp[ 'sign_id' ] ,
+            line,
+            'vimspectorBP' if bp[ 'state' ] == 'ENABLED'
+                           else 'vimspectorBPDisabled',
+            file_name ) )
+
   def OnEvent_output( self, message ):
     with utils.ModifiableScratchBuffer( self._outputBuffer ):
       t = [ message[ 'body' ][ 'category' ] + ':' + '-' * 20 ]