Pass StartupOptions around as a const ref as much as possible

Nice for simplification and consistency, as well as following the style guide.

ComputeBaseDirectories still takes a StartupOptions* since it mutates it - I'll
clean this up in another change...

I left BlazeServer's ctor as is since I want to just lift the fields that it
needs off of StartupOptions. However, I want to do this when I can guarantee in
the code that StartupOptions will no longer be mutated - this'll probably come
in the same change as touching up ComputeBaseDirectories...

RELNOTES: None
PiperOrigin-RevId: 251940659

src/main/cpp/blaze_util_darwin.cc

@@ -197,8 +197,8 @@ string GetSystemJavabase() {
 }
 
 int ConfigureDaemonProcess(posix_spawnattr_t *attrp,
-                           const StartupOptions *options) {
-  return posix_spawnattr_set_qos_class_np(attrp, options->macos_qos_class);
+                           const StartupOptions &options) {
+  return posix_spawnattr_set_qos_class_np(attrp, options.macos_qos_class);
 }
 
 void WriteSystemSpecificProcessIdentifier(

src/main/cpp/blaze_util_freebsd.cc

@@ -156,7 +156,7 @@ string GetSystemJavabase() {
 }
 
 int ConfigureDaemonProcess(posix_spawnattr_t *attrp,
-                           const StartupOptions *options) {
+                           const StartupOptions &options) {
   // No interesting platform-specific details to configure on this platform.
   return 0;
 }

src/main/cpp/blaze_util_linux.cc

@@ -205,7 +205,7 @@ static bool GetStartTime(const string& pid, string* start_time) {
 }
 
 int ConfigureDaemonProcess(posix_spawnattr_t* attrp,
-                           const StartupOptions* options) {
+                           const StartupOptions &options) {
   // No interesting platform-specific details to configure on this platform.
   return 0;
 }

src/main/cpp/blaze_util_platform.h

@@ -163,7 +163,7 @@ int ExecuteDaemon(const std::string& exe,
                   const bool daemon_output_append,
                   const std::string& binaries_dir,
                   const std::string& server_dir,
-                  const StartupOptions* options,
+                  const StartupOptions &options,
                   BlazeServerStartup** server_startup);
 
 // A character used to separate paths in a list.

src/main/cpp/blaze_util_posix.cc

@@ -339,7 +339,7 @@ bool SocketBlazeServerStartup::IsStillAlive() {
 // Returns zero on success or -1 on error, in which case errno is set to the
 // corresponding error details.
 int ConfigureDaemonProcess(posix_spawnattr_t* attrp,
-                           const StartupOptions* options);
+                           const StartupOptions &options);
 
 void WriteSystemSpecificProcessIdentifier(
     const string& server_dir, pid_t server_pid);
@@ -351,7 +351,7 @@ int ExecuteDaemon(const string& exe,
                   const bool daemon_output_append,
                   const string& binaries_dir,
                   const string& server_dir,
-                  const StartupOptions* options,
+                  const StartupOptions &options,
                   BlazeServerStartup** server_startup) {
   const string pid_file = blaze_util::JoinPath(server_dir, kServerPidFile);
   const string daemonize = blaze_util::JoinPath(binaries_dir, "daemonize");

src/main/cpp/blaze_util_windows.cc

@@ -658,7 +658,7 @@ int ExecuteDaemon(const string& exe,
                   const bool daemon_out_append,
                   const string& binaries_dir,
                   const string& server_dir,
-                  const StartupOptions* options,
+                  const StartupOptions &options,
                   BlazeServerStartup** server_startup) {
   wstring wdaemon_output;
   string error;

src/main/cpp/startup_options.cc

@@ -238,7 +238,7 @@ blaze_exit_code::ExitCode StartupOptions::ProcessArg(
              NULL) {
     // TODO(bazel-team): Consider examining the javabase and re-execing in case
     // of architecture mismatch.
-    server_javabase_ = blaze::AbsolutePathFromFlag(value);
+    explicit_server_javabase_ = blaze::AbsolutePathFromFlag(value);
     option_sources["server_javabase"] = rcfile;
   } else if ((value = GetUnaryOption(arg, next_arg, "--host_jvm_args")) !=
              NULL) {
@@ -492,10 +492,10 @@ string StartupOptions::GetEmbeddedJavabase() const {
   return "";
 }
 
-string StartupOptions::GetServerJavabase() {
+string StartupOptions::GetServerJavabase() const {
   // 1) Allow overriding the server_javabase via --server_javabase.
-  if (!server_javabase_.empty()) {
-    return server_javabase_;
+  if (!explicit_server_javabase_.empty()) {
+    return explicit_server_javabase_;
   }
   if (default_server_javabase_.empty()) {
     string bundled_jre_path = GetEmbeddedJavabase();
@@ -517,7 +517,7 @@ string StartupOptions::GetServerJavabase() {
 }
 
 string StartupOptions::GetExplicitServerJavabase() const {
-  return server_javabase_;
+  return explicit_server_javabase_;
 }
 
 string StartupOptions::GetJvm() {

src/main/cpp/startup_options.h

@@ -225,7 +225,7 @@ class StartupOptions {
 
   // Returns the GetHostJavabase. This should be called after parsing
   // the --server_javabase option.
-  std::string GetServerJavabase();
+  std::string GetServerJavabase() const;
 
   // Returns the explicit value of the --server_javabase startup option or the
   // empty string if it was not specified on the command line.
@@ -331,8 +331,12 @@ class StartupOptions {
                                        bool *is_space_separated,
                                        std::string *error);
 
-  std::string server_javabase_;
-  std::string default_server_javabase_;
+  // The server javabase as provided on the commandline.
+  std::string explicit_server_javabase_;
+
+  // The server javabase to be used (computed lazily).
+  mutable std::string default_server_javabase_;
+
   // Contains the collection of startup flags that Bazel accepts.
   std::set<std::unique_ptr<StartupFlag>> valid_startup_flags;
 };