lshal: add HelpCommand
Add *Command::usage() function for each Command and let
Lshal class to call them.
Suppress output from getopt_long and write our own
error message to customized error stream (for testing).
Test: lshal_test
Test: lshal --help
Change-Id: I8f5847c84a3e01af29fa85871479cab3baeb5312
diff --git a/cmds/lshal/HelpCommand.cpp b/cmds/lshal/HelpCommand.cpp
new file mode 100644
index 0000000..b393f05
--- /dev/null
+++ b/cmds/lshal/HelpCommand.cpp
@@ -0,0 +1,68 @@
+/*
+ * 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 {
+
+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 {
+ static const std::string help =
+ "help:\n"
+ " lshal -h\n"
+ " lshal --help\n"
+ " lshal help\n"
+ " Print this help message\n"
+ " lshal help list\n"
+ " Print help message for list\n"
+ " lshal help debug\n"
+ " Print help message for debug\n";
+
+ mLshal.err() << help;
+}
+
+} // namespace lshal
+} // namespace android
+