tools [generators]: Prefer error string over throwing

This is not a library. The tool should not recover here. Print the error
and exit the program.

Coverity-Id: 479436
Pick-to: 6.9 6.8
Change-Id: I97c24b325a037e19de17af9b246ba2bb2be76d78
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>

src/tools/qtgrpcgen/main.cpp

@@ -7,6 +7,9 @@
 #include "options.h"
 #include "utils.h"
 
+#include <iostream>
+#include <cstdlib>
+
 using namespace QtGrpc;
 
 int main(int argc, char *argv[])
@@ -14,8 +17,13 @@ int main(int argc, char *argv[])
     char *optionsPtr = getenv("QT_GRPC_OPTIONS");
     if (optionsPtr != nullptr) {
         QT_PROTOBUF_DEBUG("QT_GRPC_OPTIONS: " << optionsPtr);
-        qtprotoccommon::Options::setFromString(optionsPtr,
-                                               qtprotoccommon::Options::QtGrpcGen);
+        std::string error;
+        qtprotoccommon::Options::setFromString(optionsPtr, qtprotoccommon::Options::QtGrpcGen,
+                                               &error);
+        if (!error.empty()) {
+            std::cerr << error << std::endl;
+            return EXIT_FAILURE;
+        }
     }
     QGrpcGenerator generator;
     return ::google::protobuf::compiler::PluginMain(argc, argv, &generator);

src/tools/qtgrpcgen/qgrpcgenerator.cpp

@@ -223,6 +223,8 @@ bool QGrpcGenerator::GenerateAll(const std::vector<const FileDescriptor *> &file
                                  const std::string &parameter, GeneratorContext *generatorContext,
                                  std::string *error) const
 {
-    Options::setFromString(parameter, qtprotoccommon::Options::QtGrpcGen);
+    Options::setFromString(parameter, qtprotoccommon::Options::QtGrpcGen, error);
+    if (!error->empty())
+        return false;
     return GeneratorBase::GenerateAll(files, parameter, generatorContext, error);
 }

src/tools/qtprotobufgen/main.cpp

@@ -8,13 +8,22 @@
 #include "options.h"
 #include "utils.h"
 
+#include <iostream>
+#include <cstdlib>
+
 using namespace ::QtProtobuf;
 int main(int argc, char *argv[])
 {
     char *optionsPtr = getenv("QT_PROTOBUF_OPTIONS");
     if (optionsPtr != nullptr) {
         QT_PROTOBUF_DEBUG("QT_PROTOBUF_OPTIONS: " << optionsPtr);
-        qtprotoccommon::Options::setFromString(optionsPtr);
+        std::string error;
+        qtprotoccommon::Options::setFromString(optionsPtr, qtprotoccommon::Options::QtProtobufGen,
+                                               &error);
+        if (!error.empty()) {
+            std::cerr << error << std::endl;
+            return EXIT_FAILURE;
+        }
     }
     QProtobufGenerator generator;
     return ::google::protobuf::compiler::PluginMain(argc, argv, &generator);

src/tools/qtprotoccommon/generatorbase.cpp

@@ -28,7 +28,9 @@ bool GeneratorBase::GenerateAll(const std::vector<const FileDescriptor *> &files
     assert(!files.empty());
     assert(generatorContext != nullptr);
 
-    Options::setFromString(parameter);
+    Options::setFromString(parameter, Options::QtProtobufGen, error);
+    if (!error->empty())
+        return false;
     if (Options::instance().generateMacroExportFile()) {
         std::string exportMacroName = Options::instance().exportMacro();
         std::string exportMacroFilename = Options::instance().exportMacroFilename();

src/tools/qtprotoccommon/options.cpp

@@ -3,10 +3,9 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
 #include "options.h"
-
 #include "utils.h"
+
 #include <regex>
-#include <stdexcept>
 #include <string_view>
 
 using namespace ::qtprotoccommon;
@@ -53,7 +52,8 @@ std::string extractCompositeOptionValue(const std::string &option)
     return optionValue;
 }
 
-void Options::setFromString(const std::string &options, GeneratorType)
+void Options::setFromString(const std::string &options, GeneratorType /*unused*/,
+                            std::string *error)
 {
     Options &instance = mutableInstance();
     for (const auto &option : utils::split(options, ";")) {
@@ -77,8 +77,9 @@ void Options::setFromString(const std::string &options, GeneratorType)
             if (!export_macro_values.empty()) {
                 static const std::regex valid_c_identifier("[a-zA-Z_][0-9a-zA-Z_]*");
                 if (!std::regex_match(export_macro_values[0], valid_c_identifier)) {
-                    throw std::invalid_argument("EXPORT_MACRO '" + export_macro_values[0]
-                                                + "' is not a valid C identifier.");
+                    *error = "EXPORT_MACRO '" + export_macro_values[0]
+                        + "' is not a valid C identifier.";
+                    return;
                 }
                 instance.m_exportMacro = export_macro_values[0];
                 QT_PROTOBUF_DEBUG("set m_exportMacro: " << instance.m_exportMacro);

src/tools/qtprotoccommon/options.h

@@ -35,7 +35,7 @@ public:
     Options &operator=(Options &&) = delete;
 
     static const Options &instance();
-    static void setFromString(const std::string &options, GeneratorType type = QtProtobufGen);
+    static void setFromString(const std::string &options, GeneratorType type, std::string *error);
 
     bool hasQml() const { return m_qml; }
     bool generateComments() const { return m_generateComments; }