[lldb] Add a log dump command

Add a log dump command to dump logs to a file. This only works for
channels that have a log handler associated that supports dumping. For
now that's limited to the circular log handler, but more could be added
in the future.

Differential revision: https://reviews.llvm.org/D128557

1 files changed, 113 insertions, 0 deletions

diff --git a/lldb/source/Commands/CommandObjectLog.cpp b/lldb/source/Commands/CommandObjectLog.cpp
index 349af26..684cb35 100644
--- a/lldb/source/Commands/CommandObjectLog.cpp
+++ b/lldb/source/Commands/CommandObjectLog.cpp
@@ -56,6 +56,9 @@ static constexpr OptionEnumValues LogHandlerType() {
 #define LLDB_OPTIONS_log_enable
 #include "CommandOptions.inc"
 
+#define LLDB_OPTIONS_log_dump
+#include "CommandOptions.inc"
+
 /// Common completion logic for log enable/disable.
 static void CompleteEnableDisable(CompletionRequest &request) {
   size_t arg_index = request.GetCursorIndex();
@@ -345,6 +348,114 @@ protected:
     return result.Succeeded();
   }
 };
+class CommandObjectLogDump : public CommandObjectParsed {
+public:
+  CommandObjectLogDump(CommandInterpreter &interpreter)
+      : CommandObjectParsed(interpreter, "log dump",
+                            "dump circular buffer logs", nullptr) {
+    CommandArgumentEntry arg1;
+    CommandArgumentData channel_arg;
+
+    // Define the first (and only) variant of this arg.
+    channel_arg.arg_type = eArgTypeLogChannel;
+    channel_arg.arg_repetition = eArgRepeatPlain;
+
+    // There is only one variant this argument could be; put it into the
+    // argument entry.
+    arg1.push_back(channel_arg);
+
+    // Push the data for the first argument into the m_arguments vector.
+    m_arguments.push_back(arg1);
+  }
+
+  ~CommandObjectLogDump() override = default;
+
+  Options *GetOptions() override { return &m_options; }
+
+  class CommandOptions : public Options {
+  public:
+    CommandOptions() = default;
+
+    ~CommandOptions() override = default;
+
+    Status SetOptionValue(uint32_t option_idx, llvm::StringRef option_arg,
+                          ExecutionContext *execution_context) override {
+      Status error;
+      const int short_option = m_getopt_table[option_idx].val;
+
+      switch (short_option) {
+      case 'f':
+        log_file.SetFile(option_arg, FileSpec::Style::native);
+        FileSystem::Instance().Resolve(log_file);
+        break;
+      default:
+        llvm_unreachable("Unimplemented option");
+      }
+
+      return error;
+    }
+
+    void OptionParsingStarting(ExecutionContext *execution_context) override {
+      log_file.Clear();
+    }
+
+    llvm::ArrayRef<OptionDefinition> GetDefinitions() override {
+      return llvm::makeArrayRef(g_log_dump_options);
+    }
+
+    FileSpec log_file;
+  };
+
+  void
+  HandleArgumentCompletion(CompletionRequest &request,
+                           OptionElementVector &opt_element_vector) override {
+    CompleteEnableDisable(request);
+  }
+
+protected:
+  bool DoExecute(Args &args, CommandReturnObject &result) override {
+    if (args.empty()) {
+      result.AppendErrorWithFormat(
+          "%s takes a log channel and one or more log types.\n",
+          m_cmd_name.c_str());
+      return false;
+    }
+
+    std::unique_ptr<llvm::raw_ostream> stream_up;
+    if (m_options.log_file) {
+      const File::OpenOptions flags = File::eOpenOptionWriteOnly |
+                                      File::eOpenOptionCanCreate |
+                                      File::eOpenOptionTruncate;
+      llvm::Expected<FileUP> file = FileSystem::Instance().Open(
+          m_options.log_file, flags, lldb::eFilePermissionsFileDefault, false);
+      if (!file) {
+        result.AppendErrorWithFormat("Unable to open log file '%s': %s",
+                                     m_options.log_file.GetCString(),
+                                     llvm::toString(file.takeError()).c_str());
+        return false;
+      }
+      stream_up = std::make_unique<llvm::raw_fd_ostream>(
+          (*file)->GetDescriptor(), /*shouldClose=*/true);
+    } else {
+      stream_up = std::make_unique<llvm::raw_fd_ostream>(
+          GetDebugger().GetOutputFile().GetDescriptor(), /*shouldClose=*/false);
+    }
+
+    const std::string channel = std::string(args[0].ref());
+    std::string error;
+    llvm::raw_string_ostream error_stream(error);
+    if (Log::DumpLogChannel(channel, *stream_up, error_stream)) {
+      result.SetStatus(eReturnStatusSuccessFinishNoResult);
+    } else {
+      result.SetStatus(eReturnStatusFailed);
+      result.GetErrorStream() << error_stream.str();
+    }
+
+    return result.Succeeded();
+  }
+
+  CommandOptions m_options;
+};
 
 class CommandObjectLogTimerEnable : public CommandObjectParsed {
 public:
@@ -554,6 +665,8 @@ CommandObjectLog::CommandObjectLog(CommandInterpreter &interpreter)
                  CommandObjectSP(new CommandObjectLogDisable(interpreter)));
   LoadSubCommand("list",
                  CommandObjectSP(new CommandObjectLogList(interpreter)));
+  LoadSubCommand("dump",
+                 CommandObjectSP(new CommandObjectLogDump(interpreter)));
   LoadSubCommand("timers",
                  CommandObjectSP(new CommandObjectLogTimer(interpreter)));
 }