1 files changed, 68 insertions, 0 deletions
diff --git a/simpleperf/cmd_help.cpp b/simpleperf/cmd_help.cpp
new file mode 100644
index 00000000..bf08dba5
--- /dev/null
+++ b/simpleperf/cmd_help.cpp
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <string>
+#include <vector>
+
+#include <base/logging.h>
+
+#include "command.h"
+
+class HelpCommand : public Command {
+ public:
+  HelpCommand()
+      : Command("help", "print help information for simpleperf",
+                "Usage: simpleperf help [subcommand]\n"
+                "    Without subcommand, print short help string for every subcommand.\n"
+                "    With subcommand, print long help string for the subcommand.\n\n") {
+  }
+
+  bool Run(const std::vector<std::string>& args) override;
+
+ private:
+  void PrintShortHelp();
+  void PrintLongHelpForOneCommand(const Command& cmd);
+};
+
+bool HelpCommand::Run(const std::vector<std::string>& args) {
+  if (args.empty()) {
+    PrintShortHelp();
+  } else {
+    Command* cmd = Command::FindCommandByName(args[0]);
+    if (cmd == nullptr) {
+      LOG(ERROR) << "malformed command line: can't find help string for unknown command " << args[0];
+      LOG(ERROR) << "try using \"--help\"";
+      return false;
+    } else {
+      PrintLongHelpForOneCommand(*cmd);
+    }
+  }
+  return true;
+}
+
+void HelpCommand::PrintShortHelp() {
+  printf("Usage: simpleperf [--help] subcommand [args_for_subcommand]\n\n");
+  for (auto& command : Command::GetAllCommands()) {
+    printf("%-20s%s\n", command->Name().c_str(), command->ShortHelpString().c_str());
+  }
+}
+
+void HelpCommand::PrintLongHelpForOneCommand(const Command& command) {
+  printf("%s\n", command.LongHelpString().c_str());
+}
+
+HelpCommand help_command;