llvm-project/lldb/source/Commands/CommandObjectBreakpointCommand.cpp

//===-- CommandObjectBreakpointCommand.cpp ----------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "CommandObjectBreakpointCommand.h"
#include "CommandObjectBreakpoint.h"
#include "lldb/Core/IOHandler.h"
#include "lldb/Interpreter/CommandInterpreter.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Breakpoint/BreakpointIDList.h"
#include "lldb/Breakpoint/Breakpoint.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Breakpoint/StoppointCallbackContext.h"
#include "lldb/Core/State.h"

using namespace lldb;
using namespace lldb_private;

//-------------------------------------------------------------------------
// CommandObjectBreakpointCommandAdd
//-------------------------------------------------------------------------

class CommandObjectBreakpointCommandAdd :
    public CommandObjectParsed,
    public IOHandlerDelegateMultiline
{
public:
    CommandObjectBreakpointCommandAdd(CommandInterpreter &interpreter)
        : CommandObjectParsed(interpreter, "add",
                              "Add LLDB commands to a breakpoint, to be executed whenever the breakpoint is hit."
                              "  If no breakpoint is specified, adds the commands to the last created breakpoint.",
                              nullptr),
          IOHandlerDelegateMultiline("DONE", IOHandlerDelegate::Completion::LLDBCommand),
          m_options()
    {
        SetHelpLong (
R"(
General information about entering breakpoint commands
------------------------------------------------------

)" "This command will prompt for commands to be executed when the specified \
breakpoint is hit.  Each command is typed on its own line following the '> ' \
prompt until 'DONE' is entered." R"(

)" "Syntactic errors may not be detected when initially entered, and many \
malformed commands can silently fail when executed.  If your breakpoint commands \
do not appear to be executing, double-check the command syntax." R"(

)" "Note: You may enter any debugger command exactly as you would at the debugger \
prompt.  There is no limit to the number of commands supplied, but do NOT enter \
more than one command per line." R"(

Special information about PYTHON breakpoint commands
----------------------------------------------------

)" "You may enter either one or more lines of Python, including function \
definitions or calls to functions that will have been imported by the time \
the code executes.  Single line breakpoint commands will be interpreted 'as is' \
when the breakpoint is hit.  Multiple lines of Python will be wrapped in a \
generated function, and a call to the function will be attached to the breakpoint." R"(

This auto-generated function is passed in three arguments:

    frame:  an lldb.SBFrame object for the frame which hit breakpoint.

    bp_loc: an lldb.SBBreakpointLocation object that represents the breakpoint location that was hit.

    dict:   the python session dictionary hit.

)" "When specifying a python function with the --python-function option, you need \
to supply the function name prepended by the module name:" R"(

    --python-function myutils.breakpoint_callback

The function itself must have the following prototype:

def breakpoint_callback(frame, bp_loc, dict):
  # Your code goes here

)" "The arguments are the same as the arguments passed to generated functions as \
described above.  Note that the global variable 'lldb.frame' will NOT be updated when \
this function is called, so be sure to use the 'frame' argument. The 'frame' argument \
can get you to the thread via frame.GetThread(), the thread can get you to the \
process via thread.GetProcess(), and the process can get you back to the target \
via process.GetTarget()." R"(

)" "Important Note: As Python code gets collected into functions, access to global \
variables requires explicit scoping using the 'global' keyword.  Be sure to use correct \
Python syntax, including indentation, when entering Python breakpoint commands." R"(

Example Python one-line breakpoint command:

(lldb) breakpoint command add -s python 1
Enter your Python command(s). Type 'DONE' to end.
> print "Hit this breakpoint!"
> DONE

As a convenience, this also works for a short Python one-liner:

(lldb) breakpoint command add -s python 1 -o 'import time; print time.asctime()'
(lldb) run
Launching '.../a.out'  (x86_64)
(lldb) Fri Sep 10 12:17:45 2010
Process 21778 Stopped
* thread #1: tid = 0x2e03, 0x0000000100000de8 a.out`c + 7 at main.c:39, stop reason = breakpoint 1.1, queue = com.apple.main-thread
  36
  37   	int c(int val)
  38   	{
  39 ->	    return val + 3;
  40   	}
  41
  42   	int main (int argc, char const *argv[])

Example multiple line Python breakpoint command:

(lldb) breakpoint command add -s p 1
Enter your Python command(s). Type 'DONE' to end.
> global bp_count
> bp_count = bp_count + 1
> print "Hit this breakpoint " + repr(bp_count) + " times!"
> DONE

Example multiple line Python breakpoint command, using function definition:

(lldb) breakpoint command add -s python 1
Enter your Python command(s). Type 'DONE' to end.
> def breakpoint_output (bp_no):
>     out_string = "Hit breakpoint number " + repr (bp_no)
>     print out_string
>     return True
> breakpoint_output (1)
> DONE

)" "In this case, since there is a reference to a global variable, \
'bp_count', you will also need to make sure 'bp_count' exists and is \
initialized:" R"(

(lldb) script
>>> bp_count = 0
>>> quit()

)" "Your Python code, however organized, can optionally return a value.  \
If the returned value is False, that tells LLDB not to stop at the breakpoint \
to which the code is associated. Returning anything other than False, or even \
returning None, or even omitting a return statement entirely, will cause \
LLDB to stop." R"(

)" "Final Note: A warning that no breakpoint command was generated when there \
are no syntax errors may indicate that a function was declared but never called."
        );

        CommandArgumentEntry arg;
        CommandArgumentData bp_id_arg;

        // Define the first (and only) variant of this arg.
        bp_id_arg.arg_type = eArgTypeBreakpointID;
        bp_id_arg.arg_repetition = eArgRepeatOptional;

        // There is only one variant this argument could be; put it into the argument entry.
        arg.push_back (bp_id_arg);

        // Push the data for the first argument into the m_arguments vector.
        m_arguments.push_back (arg);
    }

    ~CommandObjectBreakpointCommandAdd() override = default;

    Options *
    GetOptions () override
    {
        return &m_options;
    }

    void
    IOHandlerActivated (IOHandler &io_handler) override
    {
        StreamFileSP output_sp(io_handler.GetOutputStreamFile());
        if (output_sp)
        {
            output_sp->PutCString(g_reader_instructions);
            output_sp->Flush();
        }
    }

    void
    IOHandlerInputComplete (IOHandler &io_handler, std::string &line) override
    {
        io_handler.SetIsDone(true);
        
        std::vector<BreakpointOptions *> *bp_options_vec = (std::vector<BreakpointOptions *> *)io_handler.GetUserData();
        for (BreakpointOptions *bp_options : *bp_options_vec)
        {
            if (!bp_options)
                continue;
                    
            std::unique_ptr<BreakpointOptions::CommandData> data_ap(new BreakpointOptions::CommandData());
            if (data_ap)
            {
                data_ap->user_source.SplitIntoLines (line.c_str(), line.size());
                BatonSP baton_sp (new BreakpointOptions::CommandBaton (data_ap.release()));
                bp_options->SetCallback (BreakpointOptionsCallbackFunction, baton_sp);
            }
        }
    }
    
    void
    CollectDataForBreakpointCommandCallback (std::vector<BreakpointOptions *> &bp_options_vec,
                                             CommandReturnObject &result)
    {
        m_interpreter.GetLLDBCommandsFromIOHandler ("> ",           // Prompt
                                                    *this,          // IOHandlerDelegate
                                                    true,           // Run IOHandler in async mode
                                                    &bp_options_vec);    // Baton for the "io_handler" that will be passed back into our IOHandlerDelegate functions
    }
    
    /// Set a one-liner as the callback for the breakpoint.
    void 
    SetBreakpointCommandCallback (std::vector<BreakpointOptions *> &bp_options_vec,
                                  const char *oneliner)
    {
        for (auto bp_options : bp_options_vec)
        {
            std::unique_ptr<BreakpointOptions::CommandData> data_ap(new BreakpointOptions::CommandData());

            // It's necessary to set both user_source and script_source to the oneliner.
            // The former is used to generate callback description (as in breakpoint command list)
            // while the latter is used for Python to interpret during the actual callback.
            data_ap->user_source.AppendString (oneliner);
            data_ap->script_source.assign (oneliner);
            data_ap->stop_on_error = m_options.m_stop_on_error;

            BatonSP baton_sp (new BreakpointOptions::CommandBaton (data_ap.release()));
            bp_options->SetCallback (BreakpointOptionsCallbackFunction, baton_sp);
        }
    }
    
    static bool
    BreakpointOptionsCallbackFunction (void *baton,
                                       StoppointCallbackContext *context, 
                                       lldb::user_id_t break_id,
                                       lldb::user_id_t break_loc_id)
    {
        bool ret_value = true;
        if (baton == nullptr)
            return true;

        BreakpointOptions::CommandData *data = (BreakpointOptions::CommandData *) baton;
        StringList &commands = data->user_source;
        
        if (commands.GetSize() > 0)
        {
            ExecutionContext exe_ctx (context->exe_ctx_ref);
            Target *target = exe_ctx.GetTargetPtr();
            if (target)
            {
                CommandReturnObject result;
                Debugger &debugger = target->GetDebugger();
                // Rig up the results secondary output stream to the debugger's, so the output will come out synchronously
                // if the debugger is set up that way.
                    
                StreamSP output_stream (debugger.GetAsyncOutputStream());
                StreamSP error_stream (debugger.GetAsyncErrorStream());
                result.SetImmediateOutputStream (output_stream);
                result.SetImmediateErrorStream (error_stream);
        
                CommandInterpreterRunOptions options;
                options.SetStopOnContinue(true);
                options.SetStopOnError (data->stop_on_error);
                options.SetEchoCommands (true);
                options.SetPrintResults (true);
                options.SetAddToHistory (false);

                debugger.GetCommandInterpreter().HandleCommands (commands,
                                                                 &exe_ctx,
                                                                 options,
                                                                 result);
                result.GetImmediateOutputStream()->Flush();
                result.GetImmediateErrorStream()->Flush();
           }
        }
        return ret_value;
    }    

    class CommandOptions : public Options
    {
    public:
        CommandOptions () :
            Options (),
            m_use_commands (false),
            m_use_script_language (false),
            m_script_language (eScriptLanguageNone),
            m_use_one_liner (false),
            m_one_liner(),
            m_function_name()
        {
        }

        ~CommandOptions() override = default;

        Error
        SetOptionValue (uint32_t option_idx, const char *option_arg,
                        ExecutionContext *execution_context) override
        {
            Error error;
            const int short_option = m_getopt_table[option_idx].val;

            switch (short_option)
            {
            case 'o':
                m_use_one_liner = true;
                m_one_liner = option_arg;
                break;

            case 's':
                m_script_language = (lldb::ScriptLanguage) Args::StringToOptionEnum (option_arg, 
                                                                                     g_option_table[option_idx].enum_values, 
                                                                                     eScriptLanguageNone,
                                                                                     error);

                if (m_script_language == eScriptLanguagePython || m_script_language == eScriptLanguageDefault)
                {
                    m_use_script_language = true;
                }
                else
                {
                    m_use_script_language = false;
                }          
                break;

            case 'e':
                {
                    bool success = false;
                    m_stop_on_error = Args::StringToBoolean(option_arg, false, &success);
                    if (!success)
                        error.SetErrorStringWithFormat("invalid value for stop-on-error: \"%s\"", option_arg);
                }
                break;
                    
            case 'F':
                m_use_one_liner = false;
                m_use_script_language = true;
                m_function_name.assign(option_arg);
                break;

            case 'D':
                m_use_dummy = true;
                break;

            default:
                break;
            }
            return error;
        }

        void
        OptionParsingStarting (ExecutionContext *execution_context) override
        {
            m_use_commands = true;
            m_use_script_language = false;
            m_script_language = eScriptLanguageNone;

            m_use_one_liner = false;
            m_stop_on_error = true;
            m_one_liner.clear();
            m_function_name.clear();
            m_use_dummy = false;
        }

        const OptionDefinition*
        GetDefinitions () override
        {
            return g_option_table;
        }

        // Options table: Required for subclasses of Options.

        static OptionDefinition g_option_table[];

        // Instance variables to hold the values for command options.

        bool m_use_commands;
        bool m_use_script_language;
        lldb::ScriptLanguage m_script_language;

        // Instance variables to hold the values for one_liner options.
        bool m_use_one_liner;
        std::string m_one_liner;
        bool m_stop_on_error;
        std::string m_function_name;
        bool m_use_dummy;
    };

protected:
    bool
    DoExecute (Args& command, CommandReturnObject &result) override
    {
        Target *target = GetSelectedOrDummyTarget(m_options.m_use_dummy);

        if (target == nullptr)
        {
            result.AppendError ("There is not a current executable; there are no breakpoints to which to add commands");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        const BreakpointList &breakpoints = target->GetBreakpointList();
        size_t num_breakpoints = breakpoints.GetSize();

        if (num_breakpoints == 0)
        {
            result.AppendError ("No breakpoints exist to have commands added");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        if (!m_options.m_use_script_language && !m_options.m_function_name.empty())
        {
            result.AppendError ("need to enable scripting to have a function run as a breakpoint command");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }
        
        BreakpointIDList valid_bp_ids;
        CommandObjectMultiwordBreakpoint::VerifyBreakpointOrLocationIDs (command, target, result, &valid_bp_ids);

        m_bp_options_vec.clear();
        
        if (result.Succeeded())
        {
            const size_t count = valid_bp_ids.GetSize();
            
            for (size_t i = 0; i < count; ++i)
            {
                BreakpointID cur_bp_id = valid_bp_ids.GetBreakpointIDAtIndex (i);
                if (cur_bp_id.GetBreakpointID() != LLDB_INVALID_BREAK_ID)
                {
                    Breakpoint *bp = target->GetBreakpointByID (cur_bp_id.GetBreakpointID()).get();
                    BreakpointOptions *bp_options = nullptr;
                    if (cur_bp_id.GetLocationID() == LLDB_INVALID_BREAK_ID)
                    {
                        // This breakpoint does not have an associated location.
                        bp_options = bp->GetOptions();
                    }
                    else                    
                    {
                        BreakpointLocationSP bp_loc_sp(bp->FindLocationByID (cur_bp_id.GetLocationID()));
                        // This breakpoint does have an associated location.
                        // Get its breakpoint options.
                        if (bp_loc_sp)
                            bp_options = bp_loc_sp->GetLocationOptions();
                    }
                    if (bp_options)
                        m_bp_options_vec.push_back (bp_options);
                }
            }

            // If we are using script language, get the script interpreter
            // in order to set or collect command callback.  Otherwise, call
            // the methods associated with this object.
            if (m_options.m_use_script_language)
            {
                ScriptInterpreter *script_interp = m_interpreter.GetScriptInterpreter();
                // Special handling for one-liner specified inline.
                if (m_options.m_use_one_liner)
                {
                    script_interp->SetBreakpointCommandCallback (m_bp_options_vec,
                                                                 m_options.m_one_liner.c_str());
                }
                else if (!m_options.m_function_name.empty())
                {
                    script_interp->SetBreakpointCommandCallbackFunction (m_bp_options_vec,
                                                                         m_options.m_function_name.c_str());
                }
                else
                {
                    script_interp->CollectDataForBreakpointCommandCallback (m_bp_options_vec,
                                                                            result);
                }
            }
            else
            {
                // Special handling for one-liner specified inline.
                if (m_options.m_use_one_liner)
                    SetBreakpointCommandCallback (m_bp_options_vec,
                                                  m_options.m_one_liner.c_str());
                else
                    CollectDataForBreakpointCommandCallback (m_bp_options_vec,
                                                             result);
            }
        }

        return result.Succeeded();
    }

private:
    CommandOptions m_options;
    std::vector<BreakpointOptions *> m_bp_options_vec;  // This stores the breakpoint options that we are currently
                                                        // collecting commands for.  In the CollectData... calls we need
                                                        // to hand this off to the IOHandler, which may run asynchronously.
                                                        // So we have to have some way to keep it alive, and not leak it.
                                                        // Making it an ivar of the command object, which never goes away
                                                        // achieves this.  Note that if we were able to run
                                                        // the same command concurrently in one interpreter we'd have to
                                                        // make this "per invocation".  But there are many more reasons
                                                        // why it is not in general safe to do that in lldb at present,
                                                        // so it isn't worthwhile to come up with a more complex mechanism
                                                        // to address this particular weakness right now.
    static const char *g_reader_instructions;
};

const char *
CommandObjectBreakpointCommandAdd::g_reader_instructions = "Enter your debugger command(s).  Type 'DONE' to end.\n";

// FIXME: "script-type" needs to have its contents determined dynamically, so somebody can add a new scripting
// language to lldb and have it pickable here without having to change this enumeration by hand and rebuild lldb proper.

static OptionEnumValueElement
g_script_option_enumeration[4] =
{
    { eScriptLanguageNone,    "command",         "Commands are in the lldb command interpreter language"},
    { eScriptLanguagePython,  "python",          "Commands are in the Python language."},
    { eSortOrderByName,       "default-script",  "Commands are in the default scripting language."},
    { 0,                      nullptr,           nullptr }
};

OptionDefinition
CommandObjectBreakpointCommandAdd::CommandOptions::g_option_table[] =
{
  // clang-format off
  {LLDB_OPT_SET_1,   false, "one-liner",         'o', OptionParser::eRequiredArgument, nullptr, nullptr,                     0, eArgTypeOneLiner,       "Specify a one-line breakpoint command inline. Be sure to surround it with quotes." },
  {LLDB_OPT_SET_ALL, false, "stop-on-error",     'e', OptionParser::eRequiredArgument, nullptr, nullptr,                     0, eArgTypeBoolean,        "Specify whether breakpoint command execution should terminate on error." },
  {LLDB_OPT_SET_ALL, false, "script-type",       's', OptionParser::eRequiredArgument, nullptr, g_script_option_enumeration, 0, eArgTypeNone,           "Specify the language for the commands - if none is specified, the lldb command interpreter will be used."},
  {LLDB_OPT_SET_2,   false, "python-function",   'F', OptionParser::eRequiredArgument, nullptr, nullptr,                     0, eArgTypePythonFunction, "Give the name of a Python function to run as command for this breakpoint. Be sure to give a module name if appropriate."},
  {LLDB_OPT_SET_ALL, false, "dummy-breakpoints", 'D', OptionParser::eNoArgument,       nullptr, nullptr,                     0, eArgTypeNone,           "Sets Dummy breakpoints - i.e. breakpoints set before a file is provided, which prime new targets."},
  {0, false, nullptr, 0, 0, nullptr, nullptr, 0, eArgTypeNone, nullptr}
  // clang-format on
};

//-------------------------------------------------------------------------
// CommandObjectBreakpointCommandDelete
//-------------------------------------------------------------------------

class CommandObjectBreakpointCommandDelete : public CommandObjectParsed
{
public:
    CommandObjectBreakpointCommandDelete (CommandInterpreter &interpreter) :
        CommandObjectParsed(interpreter,
                            "delete",
                            "Delete the set of commands from a breakpoint.",
                            nullptr),
        m_options()
    {
        CommandArgumentEntry arg;
        CommandArgumentData bp_id_arg;

        // Define the first (and only) variant of this arg.
        bp_id_arg.arg_type = eArgTypeBreakpointID;
        bp_id_arg.arg_repetition = eArgRepeatPlain;

        // There is only one variant this argument could be; put it into the argument entry.
        arg.push_back (bp_id_arg);

        // Push the data for the first argument into the m_arguments vector.
        m_arguments.push_back (arg);
    }

    ~CommandObjectBreakpointCommandDelete() override = default;

    Options *
    GetOptions () override
    {
        return &m_options;
    }

    class CommandOptions : public Options
    {
    public:
        CommandOptions() :
            Options(),
            m_use_dummy(false)
        {
        }

        ~CommandOptions() override = default;

        Error
        SetOptionValue (uint32_t option_idx, const char *option_arg,
                        ExecutionContext *execution_context) override
        {
            Error error;
            const int short_option = m_getopt_table[option_idx].val;

            switch (short_option)
            {
                case 'D':
                    m_use_dummy = true;
                    break;

                default:
                    error.SetErrorStringWithFormat ("unrecognized option '%c'", short_option);
                    break;
            }

            return error;
        }

        void
        OptionParsingStarting (ExecutionContext *execution_context) override
        {
            m_use_dummy = false;
        }

        const OptionDefinition*
        GetDefinitions () override
        {
            return g_option_table;
        }

        // Options table: Required for subclasses of Options.

        static OptionDefinition g_option_table[];

        // Instance variables to hold the values for command options.
        bool m_use_dummy;
    };

protected:
    bool
    DoExecute (Args& command, CommandReturnObject &result) override
    {
        Target *target = GetSelectedOrDummyTarget(m_options.m_use_dummy);

        if (target == nullptr)
        {
            result.AppendError ("There is not a current executable; there are no breakpoints from which to delete commands");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        const BreakpointList &breakpoints = target->GetBreakpointList();
        size_t num_breakpoints = breakpoints.GetSize();

        if (num_breakpoints == 0)
        {
            result.AppendError ("No breakpoints exist to have commands deleted");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        if (command.GetArgumentCount() == 0)
        {
            result.AppendError ("No breakpoint specified from which to delete the commands");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        BreakpointIDList valid_bp_ids;
        CommandObjectMultiwordBreakpoint::VerifyBreakpointOrLocationIDs (command, target, result, &valid_bp_ids);

        if (result.Succeeded())
        {
            const size_t count = valid_bp_ids.GetSize();
            for (size_t i = 0; i < count; ++i)
            {
                BreakpointID cur_bp_id = valid_bp_ids.GetBreakpointIDAtIndex (i);
                if (cur_bp_id.GetBreakpointID() != LLDB_INVALID_BREAK_ID)
                {
                    Breakpoint *bp = target->GetBreakpointByID (cur_bp_id.GetBreakpointID()).get();
                    if (cur_bp_id.GetLocationID() != LLDB_INVALID_BREAK_ID)
                    {
                        BreakpointLocationSP bp_loc_sp (bp->FindLocationByID (cur_bp_id.GetLocationID()));
                        if (bp_loc_sp)
                            bp_loc_sp->ClearCallback();
                        else
                        {
                            result.AppendErrorWithFormat("Invalid breakpoint ID: %u.%u.\n", 
                                                         cur_bp_id.GetBreakpointID(),
                                                         cur_bp_id.GetLocationID());
                            result.SetStatus (eReturnStatusFailed);
                            return false;
                        }
                    }
                    else
                    {
                        bp->ClearCallback();
                    }
                }
            }
        }
        return result.Succeeded();
    }

private:
    CommandOptions m_options;
};

OptionDefinition
CommandObjectBreakpointCommandDelete::CommandOptions::g_option_table[] =
{
  // clang-format off
  {LLDB_OPT_SET_1, false, "dummy-breakpoints", 'D', OptionParser::eNoArgument, nullptr, nullptr, 0, eArgTypeNone, "Delete commands from Dummy breakpoints - i.e. breakpoints set before a file is provided, which prime new targets."},
  {0, false, nullptr, 0, 0, nullptr, nullptr, 0, eArgTypeNone, nullptr}
  // clang-format on
};

//-------------------------------------------------------------------------
// CommandObjectBreakpointCommandList
//-------------------------------------------------------------------------

class CommandObjectBreakpointCommandList : public CommandObjectParsed
{
public:
    CommandObjectBreakpointCommandList (CommandInterpreter &interpreter) :
        CommandObjectParsed(interpreter,
                            "list",
                            "List the script or set of commands to be executed when the breakpoint is hit.",
                            nullptr)
    {
        CommandArgumentEntry arg;
        CommandArgumentData bp_id_arg;

        // Define the first (and only) variant of this arg.
        bp_id_arg.arg_type = eArgTypeBreakpointID;
        bp_id_arg.arg_repetition = eArgRepeatPlain;

        // There is only one variant this argument could be; put it into the argument entry.
        arg.push_back (bp_id_arg);

        // Push the data for the first argument into the m_arguments vector.
        m_arguments.push_back (arg);
    }

    ~CommandObjectBreakpointCommandList() override = default;

protected:
    bool
    DoExecute (Args& command,
             CommandReturnObject &result) override
    {
        Target *target = m_interpreter.GetDebugger().GetSelectedTarget().get();

        if (target == nullptr)
        {
            result.AppendError ("There is not a current executable; there are no breakpoints for which to list commands");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        const BreakpointList &breakpoints = target->GetBreakpointList();
        size_t num_breakpoints = breakpoints.GetSize();

        if (num_breakpoints == 0)
        {
            result.AppendError ("No breakpoints exist for which to list commands");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        if (command.GetArgumentCount() == 0)
        {
            result.AppendError ("No breakpoint specified for which to list the commands");
            result.SetStatus (eReturnStatusFailed);
            return false;
        }

        BreakpointIDList valid_bp_ids;
        CommandObjectMultiwordBreakpoint::VerifyBreakpointOrLocationIDs (command, target, result, &valid_bp_ids);

        if (result.Succeeded())
        {
            const size_t count = valid_bp_ids.GetSize();
            for (size_t i = 0; i < count; ++i)
            {
                BreakpointID cur_bp_id = valid_bp_ids.GetBreakpointIDAtIndex (i);
                if (cur_bp_id.GetBreakpointID() != LLDB_INVALID_BREAK_ID)
                {
                    Breakpoint *bp = target->GetBreakpointByID (cur_bp_id.GetBreakpointID()).get();
                    
                    if (bp)
                    {
                        const BreakpointOptions *bp_options = nullptr;
                        if (cur_bp_id.GetLocationID() != LLDB_INVALID_BREAK_ID)
                        {
                            BreakpointLocationSP bp_loc_sp(bp->FindLocationByID (cur_bp_id.GetLocationID()));
                            if (bp_loc_sp)
                                bp_options = bp_loc_sp->GetOptionsNoCreate();
                            else
                            {
                                result.AppendErrorWithFormat("Invalid breakpoint ID: %u.%u.\n", 
                                                             cur_bp_id.GetBreakpointID(),
                                                             cur_bp_id.GetLocationID());
                                result.SetStatus (eReturnStatusFailed);
                                return false;
                            }
                        }
                        else
                        {
                            bp_options = bp->GetOptions();
                        }

                        if (bp_options)
                        {
                            StreamString id_str;
                            BreakpointID::GetCanonicalReference (&id_str, 
                                                                 cur_bp_id.GetBreakpointID(), 
                                                                 cur_bp_id.GetLocationID());
                            const Baton *baton = bp_options->GetBaton();
                            if (baton)
                            {
                                result.GetOutputStream().Printf ("Breakpoint %s:\n", id_str.GetData());
                                result.GetOutputStream().IndentMore ();
                                baton->GetDescription(&result.GetOutputStream(), eDescriptionLevelFull);
                                result.GetOutputStream().IndentLess ();
                            }
                            else
                            {
                                result.AppendMessageWithFormat ("Breakpoint %s does not have an associated command.\n", 
                                                                id_str.GetData());
                            }
                        }
                        result.SetStatus (eReturnStatusSuccessFinishResult);
                    }
                    else
                    {
                        result.AppendErrorWithFormat("Invalid breakpoint ID: %u.\n", cur_bp_id.GetBreakpointID());
                        result.SetStatus (eReturnStatusFailed);
                    }
                }
            }
        }

        return result.Succeeded();
    }
};

//-------------------------------------------------------------------------
// CommandObjectBreakpointCommand
//-------------------------------------------------------------------------

CommandObjectBreakpointCommand::CommandObjectBreakpointCommand(CommandInterpreter &interpreter)
    : CommandObjectMultiword(
          interpreter, "command",
          "Commands for adding, removing and listing LLDB commands executed when a breakpoint is hit.",
          "command <sub-command> [<sub-command-options>] <breakpoint-id>")
{
    CommandObjectSP add_command_object (new CommandObjectBreakpointCommandAdd (interpreter));
    CommandObjectSP delete_command_object (new CommandObjectBreakpointCommandDelete (interpreter));
    CommandObjectSP list_command_object (new CommandObjectBreakpointCommandList (interpreter));

    add_command_object->SetCommandName ("breakpoint command add");
    delete_command_object->SetCommandName ("breakpoint command delete");
    list_command_object->SetCommandName ("breakpoint command list");

    LoadSubCommand ("add",    add_command_object);
    LoadSubCommand ("delete", delete_command_object);
    LoadSubCommand ("list",   list_command_object);
}

CommandObjectBreakpointCommand::~CommandObjectBreakpointCommand() = default;