[lldb-dap] Creating an API for sending dap events from a script in lldb-dap. (#112384)

ashgti · web-flow · commit c5c11f340436 · 2024-10-16T17:19:51.000-07:00
Custom DAP events can be detected using https://code.visualstudio.com/api/references/vscode-api#debug.onDidReceiveDebugSessionCustomEvent. This API allows an lldb python script to send events to the DAP client to allow extensions to handle these custom events.
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
@@ -1267,7 +1267,7 @@ def run_vscode(dbg, args, options):
 def main():
     parser = optparse.OptionParser(
         description=(
-            "A testing framework for the Visual Studio Code Debug " "Adaptor protocol"
+            "A testing framework for the Visual Studio Code Debug Adaptor protocol"
         )
     )
 
diff --git a/lldb/test/API/tools/lldb-dap/send-event/Makefile b/lldb/test/API/tools/lldb-dap/send-event/Makefile
@@ -0,0 +1,3 @@
+C_SOURCES := main.c
+
+include Makefile.rules
diff --git a/lldb/test/API/tools/lldb-dap/send-event/TestDAP_sendEvent.py b/lldb/test/API/tools/lldb-dap/send-event/TestDAP_sendEvent.py
@@ -0,0 +1,67 @@
+"""
+Test lldb-dap send-event integration.
+"""
+
+import json
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+import lldbdap_testcase
+
+
+class TestDAP_sendEvent(lldbdap_testcase.DAPTestCaseBase):
+    def test_send_event(self):
+        """
+        Test sending a custom event.
+        """
+        program = self.getBuildArtifact("a.out")
+        source = "main.c"
+        custom_event_body = {
+            "key": 321,
+            "arr": [True],
+        }
+        self.build_and_launch(
+            program,
+            stopCommands=[
+                "lldb-dap send-event my-custom-event-no-body",
+                "lldb-dap send-event my-custom-event '{}'".format(
+                    json.dumps(custom_event_body)
+                ),
+            ],
+        )
+
+        breakpoint_line = line_number(source, "// breakpoint")
+
+        self.set_source_breakpoints(source, [breakpoint_line])
+        self.continue_to_next_stop()
+
+        custom_event = self.dap_server.wait_for_event(
+            filter=["my-custom-event-no-body"]
+        )
+        self.assertEquals(custom_event["event"], "my-custom-event-no-body")
+        self.assertIsNone(custom_event.get("body", None))
+
+        custom_event = self.dap_server.wait_for_event(filter=["my-custom-event"])
+        self.assertEquals(custom_event["event"], "my-custom-event")
+        self.assertEquals(custom_event["body"], custom_event_body)
+
+    def test_send_internal_event(self):
+        """
+        Test sending an internal event produces an error.
+        """
+        program = self.getBuildArtifact("a.out")
+        source = "main.c"
+        self.build_and_launch(program)
+
+        breakpoint_line = line_number(source, "// breakpoint")
+
+        self.set_source_breakpoints(source, [breakpoint_line])
+        self.continue_to_next_stop()
+
+        resp = self.dap_server.request_evaluate(
+            "`lldb-dap send-event stopped", context="repl"
+        )
+        self.assertRegex(
+            resp["body"]["result"],
+            r"Invalid use of lldb-dap send-event, event \"stopped\" should be handled by lldb-dap internally.",
+        )
diff --git a/lldb/test/API/tools/lldb-dap/send-event/main.c b/lldb/test/API/tools/lldb-dap/send-event/main.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main(int argc, char const *argv[]) {
+  printf("example\n"); // breakpoint 1
+  return 0;
+}
diff --git a/lldb/tools/lldb-dap/DAP.cpp b/lldb/tools/lldb-dap/DAP.cpp
@@ -962,6 +962,68 @@ bool ReplModeRequestHandler::DoExecute(lldb::SBDebugger debugger,
   return true;
 }
 
+// Sends a DAP event with an optional body.
+//
+// See
+// https://code.visualstudio.com/api/references/vscode-api#debug.onDidReceiveDebugSessionCustomEvent
+bool SendEventRequestHandler::DoExecute(lldb::SBDebugger debugger,
+                                        char **command,
+                                        lldb::SBCommandReturnObject &result) {
+  // Command format like: `send-event <name> <body>?`
+  if (!command || !command[0] || llvm::StringRef(command[0]).empty()) {
+    result.SetError("Not enough arguments found, expected format "
+                    "`lldb-dap send-event <name> <body>?`.");
+    return false;
+  }
+
+  llvm::StringRef name{command[0]};
+  // Events that are stateful and should be handled by lldb-dap internally.
+  const std::array internal_events{"breakpoint", "capabilities", "continued",
+                                   "exited",     "initialize",   "loadedSource",
+                                   "module",     "process",      "stopped",
+                                   "terminated", "thread"};
+  if (std::find(internal_events.begin(), internal_events.end(), name) !=
+      std::end(internal_events)) {
+    std::string msg =
+        llvm::formatv("Invalid use of lldb-dap send-event, event \"{0}\" "
+                      "should be handled by lldb-dap internally.",
+                      name)
+            .str();
+    result.SetError(msg.c_str());
+    return false;
+  }
+
+  llvm::json::Object event(CreateEventObject(name));
+
+  if (command[1] && !llvm::StringRef(command[1]).empty()) {
+    // See if we have unused arguments.
+    if (command[2]) {
+      result.SetError(
+          "Additional arguments found, expected `lldb-dap send-event "
+          "<name> <body>?`.");
+      return false;
+    }
+
+    llvm::StringRef raw_body{command[1]};
+
+    llvm::Expected<llvm::json::Value> body = llvm::json::parse(raw_body);
+
+    if (!body) {
+      llvm::Error err = body.takeError();
+      std::string msg = "Failed to parse custom event body: " +
+                        llvm::toString(std::move(err));
+      result.SetError(msg.c_str());
+      return false;
+    }
+
+    event.try_emplace("body", std::move(*body));
+  }
+
+  g_dap.SendJSON(llvm::json::Value(std::move(event)));
+  result.SetStatus(lldb::eReturnStatusSuccessFinishNoResult);
+  return true;
+}
+
 void DAP::SetFrameFormat(llvm::StringRef format) {
   if (format.empty())
     return;
diff --git a/lldb/tools/lldb-dap/DAP.h b/lldb/tools/lldb-dap/DAP.h
@@ -144,6 +144,11 @@ struct ReplModeRequestHandler : public lldb::SBCommandPluginInterface {
                  lldb::SBCommandReturnObject &result) override;
 };
 
+struct SendEventRequestHandler : public lldb::SBCommandPluginInterface {
+  bool DoExecute(lldb::SBDebugger debugger, char **command,
+                 lldb::SBCommandReturnObject &result) override;
+};
+
 struct DAP {
   std::string debug_adaptor_path;
   InputStream input;
diff --git a/lldb/tools/lldb-dap/README.md b/lldb/tools/lldb-dap/README.md
@@ -290,6 +290,37 @@ The initial repl-mode can be configured with the cli flag `--repl-mode=<mode>`
 and may also be adjusted at runtime using the lldb command
 `lldb-dap repl-mode <mode>`.
 
+#### `lldb-dap send-event`
+
+lldb-dap includes a command to trigger a Debug Adapter Protocol event
+from a script.
+
+The event maybe a custom DAP event or a standard event, if the event is not 
+handled internally by `lldb-dap`.
+
+This command has the format:
+
+```
+lldb-dap send-event <name> <body>?
+```
+
+For example you can use a launch configuration hook to trigger custom events like:
+
+```json
+{
+  "program": "exe",
+  "stopCommands": [
+    "lldb-dap send-event MyStopEvent",
+    "lldb-dap send-event MyStopEvent '{\"key\": 321}",
+  ]
+}
+```
+
+[See the specification](https://microsoft.github.io/debug-adapter-protocol/specification#Base_Protocol_Event) 
+for more details on Debug Adapter Protocol events and the VS Code 
+[debug.onDidReceiveDebugSessionCustomEvent](https://code.visualstudio.com/api/references/vscode-api#debug.onDidReceiveDebugSessionCustomEvent) 
+API for handling a custom event from an extension.
+
 ## Contributing
 
 `lldb-dap` and `lldb` are developed under the umbrella of the [LLVM project](https://llvm.org/).
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -1896,6 +1896,8 @@ void request_initialize(const llvm::json::Object &request) {
   cmd.AddCommand(
       "repl-mode", new ReplModeRequestHandler(),
       "Get or set the repl behavior of lldb-dap evaluation requests.");
+  cmd.AddCommand("send-event", new SendEventRequestHandler(),
+                 "Sends an DAP event to the client.");
 
   g_dap.progress_event_thread = std::thread(ProgressEventThreadFunction);
 

Original file line number	Diff line number	Diff line change
`@@ -1267,7 +1267,7 @@ def run_vscode(dbg, args, options):`
`1267`	`1267`	`def main():`
`1268`	`1268`	`parser = optparse.OptionParser(`
`1269`	`1269`	`description=(`
`1270`		`- "A testing framework for the Visual Studio Code Debug " "Adaptor protocol"`
	`1270`	`+ "A testing framework for the Visual Studio Code Debug Adaptor protocol"`
`1271`	`1271`	`)`
`1272`	`1272`	`)`
`1273`	`1273`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+C_SOURCES := main.c`
	`2`	`+`
	`3`	`+include Makefile.rules`