1 files changed, 75 insertions, 0 deletions
diff --git a/cmds/lshal/HelpCommand.cpp b/cmds/lshal/HelpCommand.cpp
new file mode 100644
index 0000000000..6773ace6d2
--- /dev/null
+++ b/cmds/lshal/HelpCommand.cpp
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 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 "HelpCommand.h"
+
+#include "Lshal.h"
+
+namespace android {
+namespace lshal {
+
+std::string HelpCommand::GetName() {
+    return "help";
+}
+
+std::string HelpCommand::getSimpleDescription() const {
+    return "Print help message.";
+}
+
+Status HelpCommand::main(const Arg &arg) {
+    if (optind >= arg.argc) {
+        // `lshal help` prints global usage.
+        mLshal.usage();
+        return OK;
+    }
+    (void)usageOfCommand(arg.argv[optind]);
+    return OK;
+}
+
+Status HelpCommand::usageOfCommand(const std::string& c) const {
+    if (c.empty()) {
+        mLshal.usage();
+        return USAGE;
+    }
+    auto command = mLshal.selectCommand(c);
+    if (command == nullptr) {
+        // from HelpCommand::main, `lshal help unknown`
+        mLshal.usage();
+        return USAGE;
+    }
+
+    command->usage();
+    return USAGE;
+
+}
+
+void HelpCommand::usage() const {
+    mLshal.err()
+            << "help:" << std::endl
+            << "    lshal -h" << std::endl
+            << "    lshal --help" << std::endl
+            << "    lshal help" << std::endl
+            << "        Print this help message" << std::endl;
+    mLshal.forEachCommand([&](const Command* e) {
+        mLshal.err() << "    lshal help " << e->getName() << std::endl
+                     << "        Print help message for " << e->getName() << std::endl;
+    });
+
+}
+
+}  // namespace lshal
+}  // namespace android
+