[lldb-dap] Make connection URLs match lldb (#144770)

Use the same scheme as ConnectionFileDescriptor::Connect and use
"listen" and "accept". Addresses feedback from a Pavel in a different PR
[1].

[1] https://github.com/llvm/llvm-project/pull/143628#discussion_r2152225200

lldb/include/lldb/Host/Socket.h

@@ -74,6 +74,11 @@ public:
     ProtocolUnixAbstract
   };
 
+  enum SocketMode {
+    ModeAccept,
+    ModeConnect,
+  };
+
   struct HostAndPort {
     std::string hostname;
     uint16_t port;
@@ -83,6 +88,10 @@ public:
     }
   };
 
+  using ProtocolModePair = std::pair<SocketProtocol, SocketMode>;
+  static std::optional<ProtocolModePair>
+  GetProtocolAndMode(llvm::StringRef scheme);
+
   static const NativeSocket kInvalidSocketValue;
 
   ~Socket() override;

lldb/source/Host/common/Socket.cpp

@@ -271,7 +271,8 @@ Socket::UdpConnect(llvm::StringRef host_and_port) {
   return UDPSocket::CreateConnected(host_and_port);
 }
 
-llvm::Expected<Socket::HostAndPort> Socket::DecodeHostAndPort(llvm::StringRef host_and_port) {
+llvm::Expected<Socket::HostAndPort>
+Socket::DecodeHostAndPort(llvm::StringRef host_and_port) {
   static llvm::Regex g_regex("([^:]+|\\[[0-9a-fA-F:]+.*\\]):([0-9]+)");
   HostAndPort ret;
   llvm::SmallVector<llvm::StringRef, 3> matches;
@@ -347,8 +348,8 @@ Status Socket::Write(const void *buf, size_t &num_bytes) {
               ", src = %p, src_len = %" PRIu64 ", flags = 0) => %" PRIi64
               " (error = %s)",
               static_cast<void *>(this), static_cast<uint64_t>(m_socket), buf,
-              static_cast<uint64_t>(src_len),
-              static_cast<int64_t>(bytes_sent), error.AsCString());
+              static_cast<uint64_t>(src_len), static_cast<int64_t>(bytes_sent),
+              error.AsCString());
   }
 
   return error;
@@ -476,3 +477,28 @@ llvm::raw_ostream &lldb_private::operator<<(llvm::raw_ostream &OS,
                                             const Socket::HostAndPort &HP) {
   return OS << '[' << HP.hostname << ']' << ':' << HP.port;
 }
+
+std::optional<Socket::ProtocolModePair>
+Socket::GetProtocolAndMode(llvm::StringRef scheme) {
+  // Keep in sync with ConnectionFileDescriptor::Connect.
+  return llvm::StringSwitch<std::optional<ProtocolModePair>>(scheme)
+      .Case("listen", ProtocolModePair{SocketProtocol::ProtocolTcp,
+                                       SocketMode::ModeAccept})
+      .Cases("accept", "unix-accept",
+             ProtocolModePair{SocketProtocol::ProtocolUnixDomain,
+                              SocketMode::ModeAccept})
+      .Case("unix-abstract-accept",
+            ProtocolModePair{SocketProtocol::ProtocolUnixAbstract,
+                             SocketMode::ModeAccept})
+      .Cases("connect", "tcp-connect",
+             ProtocolModePair{SocketProtocol::ProtocolTcp,
+                              SocketMode::ModeConnect})
+      .Case("udp", ProtocolModePair{SocketProtocol::ProtocolTcp,
+                                    SocketMode::ModeConnect})
+      .Case("unix-connect", ProtocolModePair{SocketProtocol::ProtocolUnixDomain,
+                                             SocketMode::ModeConnect})
+      .Case("unix-abstract-connect",
+            ProtocolModePair{SocketProtocol::ProtocolUnixAbstract,
+                             SocketMode::ModeConnect})
+      .Default(std::nullopt);
+}

lldb/test/API/tools/lldb-dap/server/TestDAP_server.py

@@ -54,7 +54,7 @@ class TestDAP_server(lldbdap_testcase.DAPTestCaseBase):
         Test launching a binary with a lldb-dap in server mode on a specific port.
         """
         self.build()
-        (_, connection) = self.start_server(connection="tcp://localhost:0")
+        (_, connection) = self.start_server(connection="listen://localhost:0")
         self.run_debug_session(connection, "Alice")
         self.run_debug_session(connection, "Bob")
 
@@ -72,7 +72,7 @@ class TestDAP_server(lldbdap_testcase.DAPTestCaseBase):
         self.addTearDownHook(cleanup)
 
         self.build()
-        (_, connection) = self.start_server(connection="unix://" + name)
+        (_, connection) = self.start_server(connection="accept://" + name)
         self.run_debug_session(connection, "Alice")
         self.run_debug_session(connection, "Bob")
 
@@ -82,7 +82,7 @@ class TestDAP_server(lldbdap_testcase.DAPTestCaseBase):
         Test launching a binary with lldb-dap in server mode and shutting down the server while the debug session is still active.
         """
         self.build()
-        (process, connection) = self.start_server(connection="tcp://localhost:0")
+        (process, connection) = self.start_server(connection="listen://localhost:0")
         self.dap_server = dap_server.DebugAdapterServer(
             connection=connection,
         )

lldb/tools/lldb-dap/Options.td

@@ -28,8 +28,8 @@ def connection
       MetaVarName<"<connection>">,
       HelpText<
           "Communicate with the lldb-dap tool over the specified connection. "
-          "Connections are specified like 'tcp://[host]:port' or "
-          "'unix:///path'.">;
+          "Connections are specified like 'listen://[host]:port' or "
+          "'accept:///path'.">;
 
 def launch_target: S<"launch-target">,
   MetaVarName<"<target>">,

lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts

@@ -26,7 +26,7 @@ export class LLDBDapServer implements vscode.Disposable {
     args: string[],
     options?: child_process.SpawnOptionsWithoutStdio,
   ): Promise<{ host: string; port: number } | undefined> {
-    const dapArgs = [...args, "--connection", "connect://localhost:0"];
+    const dapArgs = [...args, "--connection", "listen://localhost:0" ];
     if (!(await this.shouldContinueStartup(dapPath, dapArgs))) {
       return undefined;
     }

lldb/tools/lldb-dap/tool/lldb-dap.cpp

@@ -127,7 +127,7 @@ EXAMPLES:
   parent over stdio. Passing a --connection URI will cause lldb-dap to listen
   for a connection in the specified mode.
 
-    lldb-dap --connection connection://localhost:<port>
+    lldb-dap --connection listen://localhost:<port>
 
   Passing --wait-for-debugger will pause the process at startup and wait for a
   debugger to attach to the process.
@@ -226,23 +226,32 @@ static llvm::Expected<std::pair<Socket::SocketProtocol, std::string>>
 validateConnection(llvm::StringRef conn) {
   auto uri = lldb_private::URI::Parse(conn);
 
-  if (uri && (uri->scheme == "tcp" || uri->scheme == "connect" ||
-              !uri->hostname.empty() || uri->port)) {
+  auto make_error = [conn]() -> llvm::Error {
+    return llvm::createStringError(
+        "Unsupported connection specifier, expected 'accept:///path' or "
+        "'listen://[host]:port', got '%s'.",
+        conn.str().c_str());
+  };
+
+  if (!uri)
+    return make_error();
+
+  std::optional<Socket::ProtocolModePair> protocol_and_mode =
+      Socket::GetProtocolAndMode(uri->scheme);
+  if (!protocol_and_mode || protocol_and_mode->second != Socket::ModeAccept)
+    return make_error();
+
+  if (protocol_and_mode->first == Socket::ProtocolTcp) {
     return std::make_pair(
         Socket::ProtocolTcp,
         formatv("[{0}]:{1}", uri->hostname.empty() ? "0.0.0.0" : uri->hostname,
                 uri->port.value_or(0)));
   }
 
-  if (uri && (uri->scheme == "unix" || uri->scheme == "unix-connect" ||
-              uri->path != "/")) {
+  if (protocol_and_mode->first == Socket::ProtocolUnixDomain)
     return std::make_pair(Socket::ProtocolUnixDomain, uri->path.str());
-  }
 
-  return llvm::createStringError(
-      "Unsupported connection specifier, expected 'unix-connect:///path' or "
-      "'connect://[host]:port', got '%s'.",
-      conn.str().c_str());
+  return make_error();
 }
 
 static llvm::Error