[lldb][lldb-dap] Return optional from json utils

lldb/tools/lldb-dap/BreakpointBase.cpp

@@ -13,8 +13,8 @@
 using namespace lldb_dap;
 
 BreakpointBase::BreakpointBase(DAP &d, const llvm::json::Object &obj)
-    : dap(d), condition(std::string(GetString(obj, "condition"))),
-      hitCondition(std::string(GetString(obj, "hitCondition"))) {}
+    : dap(d), condition(std::string(GetString(obj, "condition").value_or(""))),
+      hitCondition(std::string(GetString(obj, "hitCondition").value_or(""))) {}
 
 void BreakpointBase::UpdateBreakpoint(const BreakpointBase &request_bp) {
   if (condition != request_bp.condition) {

lldb/tools/lldb-dap/DAP.cpp

@@ -630,9 +630,11 @@ DAP::CreateTargetFromArguments(const llvm::json::Object &arguments,
   // enough information to determine correct arch and platform (or ELF can be
   // omitted at all), so it is good to leave the user an apportunity to specify
   // those. Any of those three can be left empty.
-  llvm::StringRef target_triple = GetString(arguments, "targetTriple");
-  llvm::StringRef platform_name = GetString(arguments, "platformName");
-  llvm::StringRef program = GetString(arguments, "program");
+  const llvm::StringRef target_triple =
+      GetString(arguments, "targetTriple").value_or("");
+  const llvm::StringRef platform_name =
+      GetString(arguments, "platformName").value_or("");
+  const llvm::StringRef program = GetString(arguments, "program").value_or("");
   auto target = this->debugger.CreateTarget(
       program.data(), target_triple.data(), platform_name.data(),
       true, // Add dependent modules.
@@ -668,7 +670,7 @@ bool DAP::HandleObject(const protocol::Message &M) {
   llvm::json::Object object = *v.getAsObject();
   const auto packet_type = GetString(object, "type");
   if (packet_type == "request") {
-    const auto command = GetString(object, "command");
+    const auto command = GetString(object, "command").value_or("");
 
     auto new_handler_pos = request_handlers.find(command);
     if (new_handler_pos != request_handlers.end()) {
@@ -704,7 +706,7 @@ bool DAP::HandleObject(const protocol::Message &M) {
         Result = std::move(*B);
       (*response_handler)(Result);
     } else {
-      llvm::StringRef message = GetString(object, "message");
+      llvm::StringRef message = GetString(object, "message").value_or("");
       if (message.empty()) {
         message = "Unknown error, response failed";
       }

lldb/tools/lldb-dap/FunctionBreakpoint.cpp

@@ -13,7 +13,8 @@
 namespace lldb_dap {
 
 FunctionBreakpoint::FunctionBreakpoint(DAP &d, const llvm::json::Object &obj)
-    : Breakpoint(d, obj), functionName(std::string(GetString(obj, "name"))) {}
+    : Breakpoint(d, obj),
+      functionName(std::string(GetString(obj, "name").value_or(""))) {}
 
 void FunctionBreakpoint::SetBreakpoint() {
   if (functionName.empty())

lldb/tools/lldb-dap/Handler/AttachRequestHandler.cpp

@@ -58,7 +58,7 @@ void AttachRequestHandler::operator()(const llvm::json::Object &request) const {
   const auto gdb_remote_port =
       GetInteger<uint64_t>(arguments, "gdb-remote-port").value_or(invalid_port);
   const auto gdb_remote_hostname =
-      GetString(arguments, "gdb-remote-hostname", "localhost");
+      GetString(arguments, "gdb-remote-hostname").value_or("localhost");
   if (pid != LLDB_INVALID_PROCESS_ID)
     attach_info.SetProcessID(pid);
   const auto wait_for = GetBoolean(arguments, "waitFor").value_or(false);
@@ -69,23 +69,25 @@ void AttachRequestHandler::operator()(const llvm::json::Object &request) const {
   dap.exit_commands = GetStrings(arguments, "exitCommands");
   dap.terminate_commands = GetStrings(arguments, "terminateCommands");
   auto attachCommands = GetStrings(arguments, "attachCommands");
-  llvm::StringRef core_file = GetString(arguments, "coreFile");
-  const auto timeout_seconds =
+  llvm::StringRef core_file = GetString(arguments, "coreFile").value_or("");
+  const uint64_t timeout_seconds =
       GetInteger<uint64_t>(arguments, "timeout").value_or(30);
   dap.stop_at_entry = core_file.empty()
                           ? GetBoolean(arguments, "stopOnEntry").value_or(false)
                           : true;
   dap.post_run_commands = GetStrings(arguments, "postRunCommands");
-  const llvm::StringRef debuggerRoot = GetString(arguments, "debuggerRoot");
+  const llvm::StringRef debuggerRoot =
+      GetString(arguments, "debuggerRoot").value_or("");
   dap.enable_auto_variable_summaries =
       GetBoolean(arguments, "enableAutoVariableSummaries").value_or(false);
   dap.enable_synthetic_child_debugging =
       GetBoolean(arguments, "enableSyntheticChildDebugging").value_or(false);
   dap.display_extended_backtrace =
       GetBoolean(arguments, "displayExtendedBacktrace").value_or(false);
-  dap.command_escape_prefix = GetString(arguments, "commandEscapePrefix", "`");
-  dap.SetFrameFormat(GetString(arguments, "customFrameFormat"));
-  dap.SetThreadFormat(GetString(arguments, "customThreadFormat"));
+  dap.command_escape_prefix =
+      GetString(arguments, "commandEscapePrefix").value_or("`");
+  dap.SetFrameFormat(GetString(arguments, "customFrameFormat").value_or(""));
+  dap.SetThreadFormat(GetString(arguments, "customThreadFormat").value_or(""));
 
   PrintWelcomeMessage();
 

lldb/tools/lldb-dap/Handler/BreakpointLocationsHandler.cpp

@@ -130,7 +130,7 @@ void BreakpointLocationsRequestHandler::operator()(
   FillResponse(request, response);
   auto *arguments = request.getObject("arguments");
   auto *source = arguments->getObject("source");
-  std::string path = GetString(source, "path").str();
+  std::string path = GetString(source, "path").value_or("").str();
   const auto start_line = GetInteger<uint64_t>(arguments, "line")
                               .value_or(LLDB_INVALID_LINE_NUMBER);
   const auto start_column = GetInteger<uint64_t>(arguments, "column")

lldb/tools/lldb-dap/Handler/CompileUnitsRequestHandler.cpp

@@ -60,7 +60,8 @@ void CompileUnitsRequestHandler::operator()(
   llvm::json::Object body;
   llvm::json::Array units;
   const auto *arguments = request.getObject("arguments");
-  std::string module_id = std::string(GetString(arguments, "moduleId"));
+  const std::string module_id =
+      GetString(arguments, "moduleId").value_or("").str();
   int num_modules = dap.target.GetNumModules();
   for (int i = 0; i < num_modules; i++) {
     auto curr_module = dap.target.GetModuleAtIndex(i);

lldb/tools/lldb-dap/Handler/CompletionsHandler.cpp

@@ -142,7 +142,7 @@ void CompletionsRequestHandler::operator()(
     frame.GetThread().SetSelectedFrame(frame.GetFrameID());
   }
 
-  std::string text = GetString(arguments, "text").str();
+  std::string text = GetString(arguments, "text").value_or("").str();
   auto original_column =
       GetInteger<int64_t>(arguments, "column").value_or(text.size());
   auto original_line = GetInteger<int64_t>(arguments, "line").value_or(1);

lldb/tools/lldb-dap/Handler/DataBreakpointInfoRequestHandler.cpp

@@ -117,7 +117,7 @@ void DataBreakpointInfoRequestHandler::operator()(
   const auto *arguments = request.getObject("arguments");
   const auto variablesReference =
       GetInteger<uint64_t>(arguments, "variablesReference").value_or(0);
-  llvm::StringRef name = GetString(arguments, "name");
+  llvm::StringRef name = GetString(arguments, "name").value_or("");
   lldb::SBFrame frame = dap.GetLLDBFrame(*arguments);
   lldb::SBValue variable = dap.variables.FindVariable(variablesReference, name);
   std::string addr, size;

lldb/tools/lldb-dap/Handler/DisassembleRequestHandler.cpp

@@ -93,7 +93,8 @@ void DisassembleRequestHandler::operator()(
   FillResponse(request, response);
   auto *arguments = request.getObject("arguments");
 
-  llvm::StringRef memoryReference = GetString(arguments, "memoryReference");
+  llvm::StringRef memoryReference =
+      GetString(arguments, "memoryReference").value_or("");
   auto addr_opt = DecodeMemoryReference(memoryReference);
   if (!addr_opt.has_value()) {
     response["success"] = false;

lldb/tools/lldb-dap/Handler/EvaluateRequestHandler.cpp

@@ -145,8 +145,9 @@ void EvaluateRequestHandler::operator()(
   llvm::json::Object body;
   const auto *arguments = request.getObject("arguments");
   lldb::SBFrame frame = dap.GetLLDBFrame(*arguments);
-  std::string expression = GetString(arguments, "expression").str();
-  llvm::StringRef context = GetString(arguments, "context");
+  std::string expression =
+      GetString(arguments, "expression").value_or("").str();
+  const llvm::StringRef context = GetString(arguments, "context").value_or("");
   bool repeat_last_command =
       expression.empty() && dap.last_nonempty_var_expression.empty();
 

lldb/tools/lldb-dap/Handler/LaunchRequestHandler.cpp

@@ -61,16 +61,18 @@ void LaunchRequestHandler::operator()(const llvm::json::Object &request) const {
   dap.terminate_commands = GetStrings(arguments, "terminateCommands");
   dap.post_run_commands = GetStrings(arguments, "postRunCommands");
   dap.stop_at_entry = GetBoolean(arguments, "stopOnEntry").value_or(false);
-  const llvm::StringRef debuggerRoot = GetString(arguments, "debuggerRoot");
+  const llvm::StringRef debuggerRoot =
+      GetString(arguments, "debuggerRoot").value_or("");
   dap.enable_auto_variable_summaries =
       GetBoolean(arguments, "enableAutoVariableSummaries").value_or(false);
   dap.enable_synthetic_child_debugging =
       GetBoolean(arguments, "enableSyntheticChildDebugging").value_or(false);
   dap.display_extended_backtrace =
       GetBoolean(arguments, "displayExtendedBacktrace").value_or(false);
-  dap.command_escape_prefix = GetString(arguments, "commandEscapePrefix", "`");
-  dap.SetFrameFormat(GetString(arguments, "customFrameFormat"));
-  dap.SetThreadFormat(GetString(arguments, "customThreadFormat"));
+  dap.command_escape_prefix =
+      GetString(arguments, "commandEscapePrefix").value_or("`");
+  dap.SetFrameFormat(GetString(arguments, "customFrameFormat").value_or(""));
+  dap.SetThreadFormat(GetString(arguments, "customThreadFormat").value_or(""));
 
   PrintWelcomeMessage();
 

lldb/tools/lldb-dap/Handler/ReadMemoryRequestHandler.cpp

@@ -98,7 +98,8 @@ void ReadMemoryRequestHandler::operator()(
   FillResponse(request, response);
   auto *arguments = request.getObject("arguments");
 
-  llvm::StringRef memoryReference = GetString(arguments, "memoryReference");
+  llvm::StringRef memoryReference =
+      GetString(arguments, "memoryReference").value_or("");
   auto addr_opt = DecodeMemoryReference(memoryReference);
   if (!addr_opt.has_value()) {
     response["success"] = false;

lldb/tools/lldb-dap/Handler/RequestHandler.cpp

@@ -54,7 +54,7 @@ void RequestHandler::SetSourceMapFromArguments(
   std::string sourceMapCommand;
   llvm::raw_string_ostream strm(sourceMapCommand);
   strm << "settings set target.source-map ";
-  const auto sourcePath = GetString(arguments, "sourcePath");
+  const auto sourcePath = GetString(arguments, "sourcePath").value_or("");
 
   // sourceMap is the new, more general form of sourcePath and overrides it.
   constexpr llvm::StringRef sourceMapKey = "sourceMap";
@@ -169,7 +169,7 @@ RequestHandler::LaunchProcess(const llvm::json::Object &request) const {
 
   // Grab the current working directory if there is one and set it in the
   // launch info.
-  const auto cwd = GetString(arguments, "cwd");
+  const auto cwd = GetString(arguments, "cwd").value_or("");
   if (!cwd.empty())
     launch_info.SetWorkingDirectory(cwd.data());
 

lldb/tools/lldb-dap/Handler/SetBreakpointsRequestHandler.cpp

@@ -130,7 +130,7 @@ void SetBreakpointsRequestHandler::operator()(
   FillResponse(request, response);
   const auto *arguments = request.getObject("arguments");
   const auto *source = arguments->getObject("source");
-  const auto path = GetString(source, "path");
+  const auto path = GetString(source, "path").value_or("");
   const auto *breakpoints = arguments->getArray("breakpoints");
   llvm::json::Array response_breakpoints;
 

lldb/tools/lldb-dap/Handler/SetVariableRequestHandler.cpp

@@ -116,9 +116,9 @@ void SetVariableRequestHandler::operator()(
   // This is a reference to the containing variable/scope
   const auto variablesReference =
       GetInteger<uint64_t>(arguments, "variablesReference").value_or(0);
-  llvm::StringRef name = GetString(arguments, "name");
+  llvm::StringRef name = GetString(arguments, "name").value_or("");
 
-  const auto value = GetString(arguments, "value");
+  const auto value = GetString(arguments, "value").value_or("");
   // Set success to false just in case we don't find the variable by name
   response.try_emplace("success", false);
 

lldb/tools/lldb-dap/InstructionBreakpoint.cpp

@@ -22,6 +22,7 @@ InstructionBreakpoint::InstructionBreakpoint(DAP &d,
     : Breakpoint(d, obj), instructionAddressReference(LLDB_INVALID_ADDRESS),
       offset(GetInteger<int64_t>(obj, "offset").value_or(0)) {
   GetString(obj, "instructionReference")
+      .value_or("")
       .getAsInteger(0, instructionAddressReference);
   instructionAddressReference += offset;
 }

lldb/tools/lldb-dap/JSONUtils.cpp

@@ -70,34 +70,17 @@ llvm::StringRef GetAsString(const llvm::json::Value &value) {
 }
 
 // Gets a string from a JSON object using the key, or returns an empty string.
-llvm::StringRef GetString(const llvm::json::Object &obj, llvm::StringRef key,
-                          llvm::StringRef defaultValue) {
-  if (std::optional<llvm::StringRef> value = obj.getString(key))
-    return *value;
-  return defaultValue;
+std::optional<llvm::StringRef> GetString(const llvm::json::Object &obj,
+                                         llvm::StringRef key) {
+  return obj.getString(key);
 }
 
-llvm::StringRef GetString(const llvm::json::Object *obj, llvm::StringRef key,
-                          llvm::StringRef defaultValue) {
+std::optional<llvm::StringRef> GetString(const llvm::json::Object *obj,
+                                         llvm::StringRef key) {
   if (obj == nullptr)
-    return defaultValue;
-  return GetString(*obj, key, defaultValue);
-}
-
-// Gets an unsigned integer from a JSON object using the key, or returns the
-// specified fail value.
-uint64_t GetUnsigned(const llvm::json::Object &obj, llvm::StringRef key,
-                     uint64_t fail_value) {
-  if (auto value = obj.getInteger(key))
-    return (uint64_t)*value;
-  return fail_value;
-}
+    return std::nullopt;
 
-uint64_t GetUnsigned(const llvm::json::Object *obj, llvm::StringRef key,
-                     uint64_t fail_value) {
-  if (obj == nullptr)
-    return fail_value;
-  return GetUnsigned(*obj, key, fail_value);
+  return GetString(*obj, key);
 }
 
 std::optional<bool> GetBoolean(const llvm::json::Object &obj,
@@ -116,6 +99,19 @@ std::optional<bool> GetBoolean(const llvm::json::Object *obj,
   return std::nullopt;
 }
 
+std::optional<int64_t> GetSigned(const llvm::json::Object &obj,
+                                 llvm::StringRef key) {
+  return obj.getInteger(key);
+}
+
+std::optional<int64_t> GetSigned(const llvm::json::Object *obj,
+                                 llvm::StringRef key) {
+  if (obj == nullptr)
+    return std::nullopt;
+
+  return GetSigned(*obj, key);
+}
+
 bool ObjectContainsKey(const llvm::json::Object &obj, llvm::StringRef key) {
   return obj.find(key) != obj.end();
 }
@@ -265,8 +261,9 @@ void FillResponse(const llvm::json::Object &request,
   // to true by default.
   response.try_emplace("type", "response");
   response.try_emplace("seq", (int64_t)0);
-  EmplaceSafeString(response, "command", GetString(request, "command"));
-  const auto seq = GetInteger<int64_t>(request, "seq").value_or(0);
+  EmplaceSafeString(response, "command",
+                    GetString(request, "command").value_or(""));
+  const int64_t seq = GetSigned(request, "seq").value_or(0);
   response.try_emplace("request_seq", seq);
   response.try_emplace("success", true);
 }
@@ -1439,13 +1436,14 @@ CreateRunInTerminalReverseRequest(const llvm::json::Object &launch_request,
     args.push_back(std::to_string(debugger_pid));
   }
   args.push_back("--launch-target");
-  args.push_back(GetString(launch_request_arguments, "program").str());
+  args.push_back(
+      GetString(launch_request_arguments, "program").value_or("").str());
   std::vector<std::string> target_args =
       GetStrings(launch_request_arguments, "args");
   args.insert(args.end(), target_args.begin(), target_args.end());
   run_in_terminal_args.try_emplace("args", args);
 
-  const auto cwd = GetString(launch_request_arguments, "cwd");
+  const auto cwd = GetString(launch_request_arguments, "cwd").value_or("");
   if (!cwd.empty())
     run_in_terminal_args.try_emplace("cwd", cwd);
 

lldb/tools/lldb-dap/JSONUtils.h

@@ -62,17 +62,14 @@ llvm::StringRef GetAsString(const llvm::json::Value &value);
 /// \param[in] key
 ///     The key to use when extracting the value
 ///
-/// \param[in] defaultValue
-///     The default value to return if the key is not present
-///
 /// \return
 ///     A llvm::StringRef that contains the string value for the
-///     specified \a key, or the default value if there is no key that
+///     specified \a key, or \a std::nullopt if there is no key that
 ///     matches or if the value is not a string.
-llvm::StringRef GetString(const llvm::json::Object &obj, llvm::StringRef key,
-                          llvm::StringRef defaultValue = {});
-llvm::StringRef GetString(const llvm::json::Object *obj, llvm::StringRef key,
-                          llvm::StringRef defaultValue = {});
+std::optional<llvm::StringRef> GetString(const llvm::json::Object &obj,
+                                         llvm::StringRef key);
+std::optional<llvm::StringRef> GetString(const llvm::json::Object *obj,
+                                         llvm::StringRef key);
 
 /// Extract the integer value for the specified key from the specified object
 /// and return it as the specified integer type T.

lldb/tools/lldb-dap/SourceBreakpoint.cpp

@@ -26,7 +26,7 @@ namespace lldb_dap {
 
 SourceBreakpoint::SourceBreakpoint(DAP &dap, const llvm::json::Object &obj)
     : Breakpoint(dap, obj),
-      logMessage(std::string(GetString(obj, "logMessage"))),
+      logMessage(GetString(obj, "logMessage").value_or("").str()),
       line(
           GetInteger<uint64_t>(obj, "line").value_or(LLDB_INVALID_LINE_NUMBER)),
       column(GetInteger<uint64_t>(obj, "column")

lldb/tools/lldb-dap/Watchpoint.cpp

@@ -20,8 +20,8 @@
 namespace lldb_dap {
 Watchpoint::Watchpoint(DAP &d, const llvm::json::Object &obj)
     : BreakpointBase(d, obj) {
-  llvm::StringRef dataId = GetString(obj, "dataId");
-  std::string accessType = GetString(obj, "accessType").str();
+  llvm::StringRef dataId = GetString(obj, "dataId").value_or("");
+  std::string accessType = GetString(obj, "accessType").value_or("").str();
   auto [addr_str, size_str] = dataId.split('/');
   llvm::to_integer(addr_str, addr, 16);
   llvm::to_integer(size_str, size);