path: root/bindings/python/clang/cindex.py

#===- cindex.py - Python Indexing Library Bindings -----------*- python -*--===#
#
#                     The LLVM Compiler Infrastructure
#
# This file is distributed under the University of Illinois Open Source
# License. See LICENSE.TXT for details.
#
#===------------------------------------------------------------------------===#

r"""
Clang Indexing Library Bindings
===============================

This module provides an interface to the Clang indexing library. It is a
low-level interface to the indexing library which attempts to match the Clang
API directly while also being "pythonic". Notable differences from the C API
are:

 * string results are returned as Python strings, not CXString objects.

 * null cursors are translated to None.

 * access to child cursors is done via iteration, not visitation.

The major indexing objects are:

  Index

    The top-level object which manages some global library state.

  TranslationUnit

    High-level object encapsulating the AST for a single translation unit. These
    can be loaded from .ast files or parsed on the fly.

  Cursor

    Generic object for representing a node in the AST.

  SourceRange, SourceLocation, and File

    Objects representing information about the input source.

Most object information is exposed using properties, when the underlying API
call is efficient.
"""

# TODO
# ====
#
# o API support for invalid translation units. Currently we can't even get the
#   diagnostics on failure because they refer to locations in an object that
#   will have been invalidated.
#
# o fix memory management issues (currently client must hold on to index and
#   translation unit, or risk crashes).
#
# o expose code completion APIs.
#
# o cleanup ctypes wrapping, would be nice to separate the ctypes details more
#   clearly, and hide from the external interface (i.e., help(cindex)).
#
# o implement additional SourceLocation, SourceRange, and File methods.

from ctypes import *

def get_cindex_library():
    # FIXME: It's probably not the case that the library is actually found in
    # this location. We need a better system of identifying and loading the
    # CIndex library. It could be on path or elsewhere, or versioned, etc.
    import platform
    name = platform.system()
    if name == 'Darwin':
        return cdll.LoadLibrary('libclang.dylib')
    elif name == 'Windows':
        return cdll.LoadLibrary('libclang.dll')
    else:
        return cdll.LoadLibrary('libclang.so')

# ctypes doesn't implicitly convert c_void_p to the appropriate wrapper
# object. This is a problem, because it means that from_parameter will see an
# integer and pass the wrong value on platforms where int != void*. Work around
# this by marshalling object arguments as void**.
c_object_p = POINTER(c_void_p)

lib = get_cindex_library()

### Structures and Utility Classes ###

class _CXString(Structure):
    """Helper for transforming CXString results."""

    _fields_ = [("spelling", c_char_p), ("free", c_int)]

    def __del__(self):
        _CXString_dispose(self)

    @staticmethod
    def from_result(res, fn, args):
        assert isinstance(res, _CXString)
        return _CXString_getCString(res)

class SourceLocation(Structure):
    """
    A SourceLocation represents a particular location within a source file.
    """
    _fields_ = [("ptr_data", c_void_p * 2), ("int_data", c_uint)]
    _data = None

    def _get_instantiation(self):
        if self._data is None:
            f, l, c, o = c_object_p(), c_uint(), c_uint(), c_uint()
            SourceLocation_loc(self, byref(f), byref(l), byref(c), byref(o))
            f = File(f) if f else None
            self._data = (f, int(l.value), int(c.value), int(c.value))
        return self._data

    @property
    def file(self):
        """Get the file represented by this source location."""
        return self._get_instantiation()[0]

    @property
    def line(self):
        """Get the line represented by this source location."""
        return self._get_instantiation()[1]

    @property
    def column(self):
        """Get the column represented by this source location."""
        return self._get_instantiation()[2]

    @property
    def offset(self):
        """Get the file offset represented by this source location."""
        return self._get_instantiation()[3]

    def __repr__(self):
        return "<SourceLocation file %r, line %r, column %r>" % (
            self.file.name if self.file else None, self.line, self.column)

class SourceRange(Structure):
    """
    A SourceRange describes a range of source locations within the source
    code.
    """
    _fields_ = [
        ("ptr_data", c_void_p * 2),
        ("begin_int_data",