[Lldb-commits] [lldb] Add the ability to define a Python based command that uses CommandObjectParsed (PR #70734)

[via lldb-commits]

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+"""
+This module implements a couple of utility classes to make writing
+lldb parsed commands more Pythonic.
+The way to use it is to make a class for you command that inherits from ParsedCommandBase.
+That will make an LLDBOVParser which you will use for your
+option definition, and to fetch option values for the current invocation
+of your command.  Access to the OV parser is through:
+
+ParsedCommandBase.get_parser()
+
+Next, implement setup_command_definition in your new command class, and call:
+
+  self.get_parser().add_option
+
+to add all your options.  The order doesn't matter for options, lldb will sort them
+alphabetically for you when it prints help.
+
+Similarly you can define the arguments with:
+
+  self.get_parser.add_argument
+
+at present, lldb doesn't do as much work as it should verifying arguments, it pretty
+much only checks that commands that take no arguments don't get passed arguments.
+
+Then implement the execute function for your command as:
+
+    def __call__(self, debugger, args_array, exe_ctx, result):
+
+The arguments will be in a python array as strings.  
+
+You can access the option values using varname you passed in when defining the option.  
+If you need to know whether a given option was set by the user or not, you can retrieve 
+the option definition array with:
+
+  self.get_options_definition()
+
+look up your element by varname and check the "_value_set" element.
+
+There are example commands in the lldb testsuite at:
+
+llvm-project/lldb/test/API/commands/command/script/add/test_commands.py
+
+FIXME: I should make a convenient wrapper for that. 
+"""
+import inspect
+import lldb
+import sys
+
+class LLDBOVParser:
+    def __init__(self):
+        self.options_array = []
+        self.args_array = []
+
+    # Some methods to translate common value types.  Should return a
+    # tuple of the value and an error value (True => error) if the
+    # type can't be converted.
+    # FIXME: Need a way to push the conversion error string back to lldb.
+    @staticmethod
+    def to_bool(in_value):
+        error = True
+        value = False
+        low_in = in_value.lower()
+        if low_in == "yes" or low_in == "true" or low_in == "1":
+            value = True
+            error = False
+            
+        if not value and low_in == "no" or low_in == "false" or low_in == "0":
+            value = False
+            error = False
+
+        return (value, error)
+
+    @staticmethod
+    def to_int(in_value):
+        #FIXME: Not doing errors yet...
+        return (int(in_value), False)
+
+    def to_unsigned(in_value):
+        # FIXME: find an unsigned converter...
+        # And handle errors.
+        return (int(in_value), False)
+
+    translators = {
+        lldb.eArgTypeBoolean : to_bool,
+        lldb.eArgTypeBreakpointID : to_unsigned,
+        lldb.eArgTypeByteSize : to_unsigned,
+        lldb.eArgTypeCount : to_unsigned,
+        lldb.eArgTypeFrameIndex : to_unsigned,
+        lldb.eArgTypeIndex : to_unsigned,
+        lldb.eArgTypeLineNum : to_unsigned,
+        lldb.eArgTypeNumLines : to_unsigned,
+        lldb.eArgTypeNumberPerLine : to_unsigned,
+        lldb.eArgTypeOffset : to_int,
+        lldb.eArgTypeThreadIndex : to_unsigned,
+        lldb.eArgTypeUnsignedInteger : to_unsigned,
+        lldb.eArgTypeWatchpointID : to_unsigned,
+        lldb.eArgTypeColumnNum : to_unsigned,
+        lldb.eArgTypeRecognizerID : to_unsigned,
+        lldb.eArgTypeTargetID : to_unsigned,
+        lldb.eArgTypeStopHookID : to_unsigned
+    }
+
+    @classmethod
+    def translate_value(cls, value_type, value):
+        error = False
+        try:
+            return cls.translators[value_type](value)
+        except KeyError:
+            # If we don't have a translator, return the string value.
+            return (value, False)
+
+    # FIXME: would this be better done on the C++ side?
+    # The common completers are missing some useful ones.
+    # For instance there really should be a common Type completer
+    # And an "lldb command name" completer.
+    completion_table = {
----------------
jimingham wrote:

The C++ side of the option specification needs work.  When you actually define an option on the C++ side, you give it an eArgType, but that doesn't actually wire up completions directly.  Instead, you have to also do that by hand.  So writing the C++ based commands in inconvenient, and would make writing ones in Python tedious as well.  I don't want people to have to get in the habit of manually doing that, so I am just providing this shim.  The change to get the ArgType -> completer working correctly is much more work, and mostly orthogonal to the main purpose of this patch.

https://github.com/llvm/llvm-project/pull/70734