view mercurial/diffhelpers.c @ 27765:f1fb93eebb1d

util: adjust hgexecutable() to handle frozen Mercurial on OS X

sys.executable is "$appbundle/Contents/MacOS/python" when Mercurial is bundled
in a frozen app bundle on OS X, so that isn't appropriate.  It appears that this
was only visible for things launched via util.system(), like external hooks,
where $HG was set wrong.

It appears that Mercurial also uses 'sys.modules['__main__'].__file__' (here)
and 'sys.argv[0]' (in platform.gethgcmd()) to figure out the command to spawn.
In both cases, this points to "$appbundle/Contents/Resources/hg", which invokes
the system python since "/usr/bin/env python" is on the shebang line.  On my
system with a screwed up python install, I get an error importing the os module
if this script is invoked.

We could take the dirname of sys.executable and join 'hg' instead of this if we
want to be paranoid, but py2app boostrap is setting the environment variable
since 0.1.6 (current version is 0.9), so it seems safe and we might as well use
it.

/*
 * diffhelpers.c - helper routines for mpatch
 *
 * Copyright 2007 Chris Mason <[e-mail]>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License v2, incorporated herein by reference.
 */

#include <Python.h>
#include <stdlib.h>
#include <string.h>

#include "util.h"

static char diffhelpers_doc[] = "Efficient diff parsing";
static PyObject *diffhelpers_Error;


/* fixup the last lines of a and b when the patch has no newline at eof */
static void _fix_newline(PyObject *hunk, PyObject *a, PyObject *b)
{
	Py_ssize_t hunksz = PyList_Size(hunk);
	PyObject *s = PyList_GET_ITEM(hunk, hunksz-1);
	char *l = PyBytes_AsString(s);
	Py_ssize_t alen = PyList_Size(a);
	Py_ssize_t blen = PyList_Size(b);
	char c = l[0];
	PyObject *hline;
	Py_ssize_t sz = PyBytes_GET_SIZE(s);

	if (sz > 1 && l[sz-2] == '\r')
		/* tolerate CRLF in last line */
		sz -= 1;

	hline = PyBytes_FromStringAndSize(l, sz-1);
	if (!hline) {
		return;
	}

	if (c == ' ' || c == '+') {
		PyObject *rline = PyBytes_FromStringAndSize(l + 1, sz - 2);
		PyList_SetItem(b, blen-1, rline);
	}
	if (c == ' ' || c == '-') {
		Py_INCREF(hline);
		PyList_SetItem(a, alen-1, hline);
	}
	PyList_SetItem(hunk, hunksz-1, hline);
}

/* python callable form of _fix_newline */
static PyObject *
fix_newline(PyObject *self, PyObject *args)
{
	PyObject *hunk, *a, *b;
	if (!PyArg_ParseTuple(args, "OOO", &hunk, &a, &b))
		return NULL;
	_fix_newline(hunk, a, b);
	return Py_BuildValue("l", 0);
}

#if (PY_VERSION_HEX < 0x02050000)
static const char *addlines_format = "OOiiOO";
#else
static const char *addlines_format = "OOnnOO";
#endif

/*
 * read lines from fp into the hunk.  The hunk is parsed into two arrays
 * a and b.  a gets the old state of the text, b gets the new state
 * The control char from the hunk is saved when inserting into a, but not b
 * (for performance while deleting files)
 */
static PyObject *
addlines(PyObject *self, PyObject *args)
{

	PyObject *fp, *hunk, *a, *b, *x;
	Py_ssize_t i;
	Py_ssize_t lena, lenb;
	Py_ssize_t num;
	Py_ssize_t todoa, todob;
	char *s, c;
	PyObject *l;
	if (!PyArg_ParseTuple(args, addlines_format,
			      &fp, &hunk, &lena, &lenb, &a, &b))
		return NULL;

	while (1) {
		todoa = lena - PyList_Size(a);
		todob = lenb - PyList_Size(b);
		num = todoa > todob ? todoa : todob;
		if (num == 0)
		    break;
		for (i = 0; i < num; i++) {
			x = PyFile_GetLine(fp, 0);
			s = PyBytes_AsString(x);
			c = *s;
			if (strcmp(s, "\\ No newline at end of file\n") == 0) {
				_fix_newline(hunk, a, b);
				continue;
			}
			if (c == '\n') {
				/* Some patches may be missing the control char
				 * on empty lines. Supply a leading space. */
				Py_DECREF(x);
				x = PyBytes_FromString(" \n");
			}
			PyList_Append(hunk, x);
			if (c == '+') {
				l = PyBytes_FromString(s + 1);
				PyList_Append(b, l);
				Py_DECREF(l);
			} else if (c == '-') {
				PyList_Append(a, x);
			} else {
				l = PyBytes_FromString(s + 1);
				PyList_Append(b, l);
				Py_DECREF(l);
				PyList_Append(a, x);
			}
			Py_DECREF(x);
		}
	}
	return Py_BuildValue("l", 0);
}

/*
 * compare the lines in a with the lines in b.  a is assumed to have
 * a control char at the start of each line, this char is ignored in the
 * compare
 */
static PyObject *
testhunk(PyObject *self, PyObject *args)
{

	PyObject *a, *b;
	long bstart;
	Py_ssize_t alen, blen;
	Py_ssize_t i;
	char *sa, *sb;

	if (!PyArg_ParseTuple(args, "OOl", &a, &b, &bstart))
		return NULL;
	alen = PyList_Size(a);
	blen = PyList_Size(b);
	if (alen > blen - bstart || bstart < 0) {
		return Py_BuildValue("l", -1);
	}
	for (i = 0; i < alen; i++) {
		sa = PyBytes_AsString(PyList_GET_ITEM(a, i));
		sb = PyBytes_AsString(PyList_GET_ITEM(b, i + bstart));
		if (strcmp(sa + 1, sb) != 0)
			return Py_BuildValue("l", -1);
	}
	return Py_BuildValue("l", 0);
}

static PyMethodDef methods[] = {
	{"addlines", addlines, METH_VARARGS, "add lines to a hunk\n"},
	{"fix_newline", fix_newline, METH_VARARGS, "fixup newline counters\n"},
	{"testhunk", testhunk, METH_VARARGS, "test lines in a hunk\n"},
	{NULL, NULL}
};

#ifdef IS_PY3K
static struct PyModuleDef diffhelpers_module = {
	PyModuleDef_HEAD_INIT,
	"diffhelpers",
	diffhelpers_doc,
	-1,
	methods
};

PyMODINIT_FUNC PyInit_diffhelpers(void)
{
	PyObject *m;

	m = PyModule_Create(&diffhelpers_module);
	if (m == NULL)
		return NULL;

	diffhelpers_Error = PyErr_NewException("diffhelpers.diffhelpersError",
											NULL, NULL);
	Py_INCREF(diffhelpers_Error);
	PyModule_AddObject(m, "diffhelpersError", diffhelpers_Error);

	return m;
}
#else
PyMODINIT_FUNC
initdiffhelpers(void)
{
	Py_InitModule3("diffhelpers", methods, diffhelpers_doc);
	diffhelpers_Error = PyErr_NewException("diffhelpers.diffhelpersError",
	                                        NULL, NULL);
}
#endif