Add the ability to define a Python based command that uses CommandObjectParsed (#70734)

This allows you to specify options and arguments and their definitions
and then have lldb handle the completions, help, etc. in the same way
that lldb does for its parsed commands internally.

This feature has some design considerations as well as the code, so I've
also set up an RFC, but I did this one first and will put the RFC
address in here once I've pushed it...

Note, the lldb "ParsedCommand interface" doesn't actually do all the
work that it should. For instance, saying the type of an option that has
a completer doesn't automatically hook up the completer, and ditto for
argument values. We also do almost no work to verify that the arguments
match their definition, or do auto-completion for them. This patch
allows you to make a command that's bug-for-bug compatible with built-in
ones, but I didn't want to stall it on getting the auto-command checking
to work all the way correctly.

As an overall design note, my primary goal here was to make an interface
that worked well in the script language. For that I needed, for
instance, to have a property-based way to get all the option values that
were specified. It was much more convenient to do that by making a
fairly bare-bones C interface to define the options and arguments of a
command, and set their values, and then wrap that in a Python class
(installed along with the other bits of the lldb python module) which
you can then derive from to make your new command. This approach will
also make it easier to experiment.

See the file test_commands.py in the test case for examples of how this
works.

1 files changed, 252 insertions, 1 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index ef7a2c1..dadcde6 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -24,6 +24,7 @@
 #include "ScriptInterpreterPythonImpl.h"
 
 #include "lldb/API/SBError.h"
+#include "lldb/API/SBExecutionContext.h"
 #include "lldb/API/SBFrame.h"
 #include "lldb/API/SBValue.h"
 #include "lldb/Breakpoint/StoppointCallbackContext.h"
@@ -531,7 +532,6 @@ void ScriptInterpreterPythonImpl::IOHandlerInputComplete(IOHandler &io_handler,
         break;
       data_up->user_source.SplitIntoLines(data);
 
-      StructuredData::ObjectSP empty_args_sp;
       if (GenerateBreakpointCommandCallbackData(data_up->user_source,
                                                 data_up->script_source,
                                                 /*has_extra_args=*/false,
@@ -2766,6 +2766,58 @@ bool ScriptInterpreterPythonImpl::RunScriptBasedCommand(
   return ret_val;
 }
 
+bool ScriptInterpreterPythonImpl::RunScriptBasedParsedCommand(
+    StructuredData::GenericSP impl_obj_sp, Args &args,
+    ScriptedCommandSynchronicity synchronicity,
+    lldb_private::CommandReturnObject &cmd_retobj, Status &error,
+    const lldb_private::ExecutionContext &exe_ctx) {
+  if (!impl_obj_sp || !impl_obj_sp->IsValid()) {
+    error.SetErrorString("no function to execute");
+    return false;
+  }
+
+  lldb::DebuggerSP debugger_sp = m_debugger.shared_from_this();
+  lldb::ExecutionContextRefSP exe_ctx_ref_sp(new ExecutionContextRef(exe_ctx));
+
+  if (!debugger_sp.get()) {
+    error.SetErrorString("invalid Debugger pointer");
+    return false;
+  }
+
+  bool ret_val = false;
+
+  std::string err_msg;
+
+  {
+    Locker py_lock(this,
+                   Locker::AcquireLock | Locker::InitSession |
+                       (cmd_retobj.GetInteractive() ? 0 : Locker::NoSTDIN),
+                   Locker::FreeLock | Locker::TearDownSession);
+
+    SynchronicityHandler synch_handler(debugger_sp, synchronicity);
+
+    StructuredData::ArraySP args_arr_sp(new StructuredData::Array());
+
+    for (const Args::ArgEntry &entry : args) {
+      args_arr_sp->AddStringItem(entry.ref());
+    }
+    StructuredDataImpl args_impl(args_arr_sp);
+    
+    ret_val = SWIGBridge::LLDBSwigPythonCallParsedCommandObject(
+        static_cast<PyObject *>(impl_obj_sp->GetValue()), debugger_sp,
+        args_impl, cmd_retobj, exe_ctx_ref_sp);
+  }
+
+  if (!ret_val)
+    error.SetErrorString("unable to execute script function");
+  else if (cmd_retobj.GetStatus() == eReturnStatusFailed)
+    return false;
+
+  error.Clear();
+  return ret_val;
+}
+
+
 /// In Python, a special attribute __doc__ contains the docstring for an object
 /// (function, method, class, ...) if any is defined Otherwise, the attribute's
 /// value is None.
@@ -2884,6 +2936,205 @@ uint32_t ScriptInterpreterPythonImpl::GetFlagsForCommandObject(
   return result;
 }
 
+StructuredData::ObjectSP 
+ScriptInterpreterPythonImpl::GetOptionsForCommandObject(
+    StructuredData::GenericSP cmd_obj_sp) {
+  StructuredData::ObjectSP result = {};
+
+  Locker py_lock(this, Locker::AcquireLock | Locker::NoSTDIN, Locker::FreeLock);
+
+  static char callee_name[] = "get_options_definition";
+
+  if (!cmd_obj_sp)
+    return result;
+
+  PythonObject implementor(PyRefType::Borrowed,
+                           (PyObject *)cmd_obj_sp->GetValue());
+
+  if (!implementor.IsAllocated())
+    return result;
+
+  PythonObject pmeth(PyRefType::Owned,
+                     PyObject_GetAttrString(implementor.get(), callee_name));
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+
+  if (!pmeth.IsAllocated())
+    return result;
+
+  if (PyCallable_Check(pmeth.get()) == 0) {
+    if (PyErr_Occurred())
+      PyErr_Clear();
+    return result;
+  }
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+
+  PythonDictionary py_return = unwrapOrSetPythonException(
+      As<PythonDictionary>(implementor.CallMethod(callee_name)));
+
+  // if it fails, print the error but otherwise go on
+  if (PyErr_Occurred()) {
+    PyErr_Print();
+    PyErr_Clear();
+    return {};
+  }
+    return py_return.CreateStructuredObject();
+}
+
+StructuredData::ObjectSP 
+ScriptInterpreterPythonImpl::GetArgumentsForCommandObject(
+    StructuredData::GenericSP cmd_obj_sp) {
+  StructuredData::ObjectSP result = {};
+
+  Locker py_lock(this, Locker::AcquireLock | Locker::NoSTDIN, Locker::FreeLock);
+
+  static char callee_name[] = "get_args_definition";
+
+  if (!cmd_obj_sp)
+    return result;
+
+  PythonObject implementor(PyRefType::Borrowed,
+                           (PyObject *)cmd_obj_sp->GetValue());
+
+  if (!implementor.IsAllocated())
+    return result;
+
+  PythonObject pmeth(PyRefType::Owned,
+                     PyObject_GetAttrString(implementor.get(), callee_name));
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+
+  if (!pmeth.IsAllocated())
+    return result;
+
+  if (PyCallable_Check(pmeth.get()) == 0) {
+    if (PyErr_Occurred())
+      PyErr_Clear();
+    return result;
+  }
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+
+  PythonList py_return = unwrapOrSetPythonException(
+      As<PythonList>(implementor.CallMethod(callee_name)));
+
+  // if it fails, print the error but otherwise go on
+  if (PyErr_Occurred()) {
+    PyErr_Print();
+    PyErr_Clear();
+    return {};
+  }
+    return py_return.CreateStructuredObject();
+}
+
+void 
+ScriptInterpreterPythonImpl::OptionParsingStartedForCommandObject(
+    StructuredData::GenericSP cmd_obj_sp) {
+
+  Locker py_lock(this, Locker::AcquireLock | Locker::NoSTDIN, Locker::FreeLock);
+
+  static char callee_name[] = "option_parsing_started";
+
+  if (!cmd_obj_sp)
+    return ;
+
+  PythonObject implementor(PyRefType::Borrowed,
+                           (PyObject *)cmd_obj_sp->GetValue());
+
+  if (!implementor.IsAllocated())
+    return;
+
+  PythonObject pmeth(PyRefType::Owned,
+                     PyObject_GetAttrString(implementor.get(), callee_name));
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+
+  if (!pmeth.IsAllocated())
+    return;
+
+  if (PyCallable_Check(pmeth.get()) == 0) {
+    if (PyErr_Occurred())
+      PyErr_Clear();
+    return;
+  }
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+
+  // option_parsing_starting doesn't return anything, ignore anything but 
+  // python errors.
+  unwrapOrSetPythonException(
+      As<bool>(implementor.CallMethod(callee_name)));
+
+  // if it fails, print the error but otherwise go on
+  if (PyErr_Occurred()) {
+    PyErr_Print();
+    PyErr_Clear();
+    return;
+  }
+}
+
+bool
+ScriptInterpreterPythonImpl::SetOptionValueForCommandObject(
+    StructuredData::GenericSP cmd_obj_sp, ExecutionContext *exe_ctx,
+    llvm::StringRef long_option, llvm::StringRef value) {
+  StructuredData::ObjectSP result = {};
+
+  Locker py_lock(this, Locker::AcquireLock | Locker::NoSTDIN, Locker::FreeLock);
+
+  static char callee_name[] = "set_option_value";
+
+  if (!cmd_obj_sp)
+    return false;
+
+  PythonObject implementor(PyRefType::Borrowed,
+                           (PyObject *)cmd_obj_sp->GetValue());
+
+  if (!implementor.IsAllocated())
+    return false;
+
+  PythonObject pmeth(PyRefType::Owned,
+                     PyObject_GetAttrString(implementor.get(), callee_name));
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+
+  if (!pmeth.IsAllocated())
+    return false;
+
+  if (PyCallable_Check(pmeth.get()) == 0) {
+    if (PyErr_Occurred())
+      PyErr_Clear();
+    return false;
+  }
+
+  if (PyErr_Occurred())
+    PyErr_Clear();
+    
+  lldb::ExecutionContextRefSP exe_ctx_ref_sp;
+  if (exe_ctx)
+    exe_ctx_ref_sp.reset(new ExecutionContextRef(exe_ctx));
+  PythonObject ctx_ref_obj = SWIGBridge::ToSWIGWrapper(exe_ctx_ref_sp);
+    
+  bool py_return = unwrapOrSetPythonException(
+      As<bool>(implementor.CallMethod(callee_name, ctx_ref_obj, long_option.str().c_str(), 
+                                      value.str().c_str())));
+
+  // if it fails, print the error but otherwise go on
+  if (PyErr_Occurred()) {
+    PyErr_Print();
+    PyErr_Clear();
+    return false;
+  }
+  return py_return;
+}
+
 bool ScriptInterpreterPythonImpl::GetLongHelpForCommandObject(
     StructuredData::GenericSP cmd_obj_sp, std::string &dest) {
   dest.clear();