Query process state from GDB via the proxy

TODO

@@ -1,5 +1,4 @@
 - Port vimscript to lua: nvimgdb.vim
-- Detect whether the debugged process is running using side channel: prompt -> paused, query on output feed timeout (test_interrupt, test_command)
 - handle <up arrow> in pywinpty PDB
 - Press any key to exit: need to unblock msvcrt.getch() somehow
 - cmake test in win32?

doc/nvimgdb.txt

@@ -427,13 +427,7 @@ Section 7.3 PDB, BashDB                            *NvimgdbPDB*  *NvimgdbBashDB*
 ==============================================================================
 Section 8: Limitations                                    *NvimgdbLimitations*
 
-- The plugin is sensitive to the debugger settings. If prompt or frame format
-  is changed, random errors may occur.
-
-- LLDB uses the same frame format in multiple different situations. The
-  command "thread backtrace", for instance, will cause jumps in the source
-  code. Workaround: execute "frame info" in the debugger or
-  `:GdbFrameUp` followed by `:GdbFrameDown`.
+- ???
 
 ==============================================================================
 Section 9: Development                                    *NvimgdbDevelopment*

lib/gdb_commands.py

@@ -69,6 +69,9 @@ def _handle_command(self, command, sock, addr):
             fname = args[0]
             self._send_response(self._get_breaks(os.path.normpath(fname)),
                                 req_id, sock, addr)
+        elif request == "get-process-state":
+            self._send_response(self._get_process_state(),
+                                req_id, sock, addr)
         elif request == "get-current-frame-location":
             self._send_response(self._get_current_frame_location(),
                                 req_id, sock, addr)
@@ -104,6 +107,19 @@ def _send_response(self, response, req_id, sock, addr):
         logger.debug("Sending response: %s", response_json)
         sock.sendto(response_json, 0, addr)
 
+    def _get_process_state(self):
+        try:
+            inferior = gdb.selected_inferior()
+            if inferior.is_valid():
+                threads = inferior.threads()
+                is_running = any((t.is_valid() and t.is_running()
+                                  for t in threads))
+                state = "running" if is_running else "stopped"
+                return state
+        except gdb.error:
+            ...
+        return "other"
+
     def _get_current_frame_location(self):
         try:
             frame = gdb.selected_frame()

lua/nvimgdb/backend/gdb.lua

@@ -31,28 +31,28 @@ function C.create_parser(actions, proxy)
 
   function P:query_paused()
     coroutine.resume(coroutine.create(function()
-      local location = proxy:query('get-current-frame-location')
-      log.debug({"current frame location", location})
-      if #location == 2 then
-        local fname = location[1]
-        local line = location[2]
-        self.actions:jump_to_source(fname, line)
+      local process_state = proxy:query('get-process-state')
+      log.debug({"process state", process_state})
+      if process_state == 'stopped' then
+        local location = proxy:query('get-current-frame-location')
+        log.debug({"current frame location", location})
+        if #location == 2 then
+          local fname = location[1]
+          local line = location[2]
+          self.actions:jump_to_source(fname, line)
+        end
       end
-    end))
-
-    coroutine.resume(coroutine.create(function()
       self.actions:query_breakpoints()
+      self.state = process_state == 'running' and self.running or self.paused
     end))
-
-    return self.paused
+    -- Don't change the state yet
+    return self.state
   end
 
-  local re_prompt = '%(gdb%) \x1a\x1a\x1a'
+  local re_prompt = '$'
   self.add_trans(self.paused, '[\r\n]Continuing%.', self._paused_continue)
   self.add_trans(self.paused, '[\r\n]Starting program:', self._paused_continue)
   self.add_trans(self.paused, re_prompt, self.query_paused)
-  self.add_trans(self.running, '%sBreakpoint %d+', self.query_paused)
-  self.add_trans(self.running, '%sTemporary breakpoint %d+', self.query_paused)
   self.add_trans(self.running, re_prompt, self.query_paused)
 
   self.state = self.running
@@ -116,7 +116,6 @@ function C.get_launch_cmd(client_cmd, tmp_dir, proxy_addr)
     file:write([[
 set confirm off
 set pagination off
-python gdb.prompt_hook = lambda p: p + ("" if p.endswith("\x01\x1a\x1a\x1a\x02") else "\x01\x1a\x1a\x1a\x02")
 ]])
     file:write("source " .. utils.get_plugin_file_path("lib", "gdb_commands.py") .. "\n")
     file:write("nvim-gdb-init " .. proxy_addr .. "\n")