[Lldb-commits] [lldb] [lldb-dap] Refactoring lldb-dap port listening mode to allow multiple connections. (PR #116392)

[Pavel Labath via lldb-commits]

================
@@ -1196,6 +1202,62 @@ def terminate(self):
             self.process.wait()
             self.process = None
 
+    @classmethod
+    def launch(
+        cls, executable: str, /, connection=None, log_file=None, env=None
+    ) -> tuple[subprocess.Popen, str]:
+        adaptor_env = os.environ.copy()
+        if env:
+            adaptor_env.update(env)
+
+        if log_file:
+            adaptor_env["LLDBDAP_LOG"] = log_file
+
+        if os.uname().sysname == "Darwin":
+            adaptor_env["NSUnbufferedIO"] = "YES"
+
+        args = [executable]
+        if connection:
+            args.append("--connection")
+            args.append(connection)
+
+        proc = subprocess.Popen(
+            args,
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=sys.stdout,
+            env=adaptor_env,
+        )
+
+        if connection:
+            # If a conneciton is specified, lldb-dap will print the listening
+            # address once the listener is made to stdout. The listener is
+            # formatted like `tcp://host:port` or `unix:///path`.
+            with selectors.DefaultSelector() as sel:
+                print("Reading stdout for the listening connection")
+                os.set_blocking(proc.stdout.fileno(), False)
+                stdout_key = sel.register(proc.stdout, selectors.EVENT_READ)
+                rdy_fds = sel.select(timeout=10.0)
----------------
labath wrote:

It looks like this will be a problem for windows (which can only `select` sockets). I can think of a couple of alternatives (writing the connection spec to a file -- and polling for it; using OS apis directly -- we have a `Pipe` class in `lldbgdbserverutils.py` for the lldb-server use case; doing a blocking read and relying on the test suite level timeout; ...), but neither of them is clearly superior.

https://github.com/llvm/llvm-project/pull/116392