Support jumping up/down the stack

Split out stack trace view into its own thing. Support jumping to code
location.

python3/vimspector/stack_trace.py

@@ -0,0 +1,69 @@
+# vimspector - A multi-language debugging system for Vim
+# Copyright 2018 Ben Jackson
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import vim
+
+from vimspector import utils
+
+_logger = logging.getLogger( __name__ )
+
+
+class StackTraceView( object ):
+  def __init__( self, session, connection, buf ):
+    self._buf = buf
+    self._session = session
+    self._connection = connection
+
+    utils.SetUpScratchBuffer( self._buf )
+    vim.current.buffer = self._buf
+    vim.command( 'nnoremap <buffer> <CR> :call vimspector#GoToFrame()<CR>' )
+
+    self._line_to_frame = {}
+
+  def LoadStackTrace( self, thread_id ):
+    self._connection.DoRequest( self._PrintStackTrace, {
+      'command': 'stackTrace',
+      'arguments': {
+        'threadId': thread_id,
+      }
+    } )
+
+  def GoToFrame( self ):
+    if vim.current.buffer != self._buf:
+      return
+
+    current_line = vim.current.window.cursor[ 0 ]
+    if current_line not in self._line_to_frame:
+      return
+
+    self._session.SetCurrentFrame( self._line_to_frame[ current_line ] )
+
+  def _PrintStackTrace( self, message ):
+    with utils.ModifiableScratchBuffer( self._buf ):
+      self._buf[:] = None
+      self._buf.append( 'Stack trace' )
+
+      stackFrames = message[ 'body' ][ 'stackFrames' ]
+
+      for frame in stackFrames:
+        self._buf.append(
+          '{0}: {1}@{2}:{3}'.format( frame[ 'id' ],
+                                     frame[ 'name' ],
+                                     frame[ 'source' ][ 'name' ],
+                                     frame[ 'line' ] ) )
+        self._line_to_frame[ len( self._buf ) ] = frame
+
+    self._session.SetCurrentFrame( stackFrames[ 0 ] )