# HG changeset patch
# User Adrian Buehlmann <adrian@cadifra.com>
# Date 2012-06-28 22:01:19
# Node ID d5422faf648cc589425cd3b0dbf1f6dbf93036a0
# Parent  9720c55d605b97065832b48d38b1d56c2db6dc2b

exewrapper: adding new exewrapper.c

diff --git a/mercurial/exewrapper.c b/mercurial/exewrapper.c
new file mode 100644
--- /dev/null
+++ b/mercurial/exewrapper.c
@@ -0,0 +1,101 @@
+/*
+ exewrapper.c - wrapper for calling a python script on Windows
+
+ Copyright 2012 Adrian Buehlmann <adrian@cadifra.com> and others
+
+ This software may be used and distributed according to the terms of the
+ GNU General Public License version 2 or any later version.
+*/
+
+#include <Python.h>
+#include <windows.h>
+
+
+#ifdef __GNUC__
+int strcat_s(char *d, size_t n, const char *s)
+{
+	return !strncat(d, s, n);
+}
+#endif
+
+
+static char pyscript[MAX_PATH + 10];
+
+int main(int argc, char *argv[])
+{
+	char *dot;
+	int ret;
+	int i;
+	int n;
+	char **pyargv;
+	WIN32_FIND_DATA fdata;
+	HANDLE hfind;
+	const char *err;
+
+	if (GetModuleFileName(NULL, pyscript, sizeof(pyscript)) == 0)
+	{
+		err = "GetModuleFileName failed";
+		goto bail;
+	}
+
+	dot = strrchr(pyscript, '.');
+	if (dot == NULL) {
+		err = "malformed module filename";
+		goto bail;
+	}
+	*dot = 0; /* cut trailing ".exe" */
+
+	hfind = FindFirstFile(pyscript, &fdata);
+	if (hfind != INVALID_HANDLE_VALUE) {
+		/* pyscript exists, close handle */
+		FindClose(hfind);
+	} else {
+		/* file pyscript isn't there, take <pyscript>exe.py */
+		strcat_s(pyscript, sizeof(pyscript), "exe.py");
+	}
+
+	/*
+	Only add the pyscript to the args, if it's not already there. It may
+	already be there, if Mercurial spawned a child process of itself, in
+	the same way as it got called, that is, with the pyscript already in
+	place. So we optionally accept the pyscript as the first argument
+	(argv[1]), letting our exe taking the role of the python interpreter.
+	*/
+	if (argc >= 2 && strcmp(argv[1], pyscript) == 0) {
+		/*
+		pyscript is already in the args, so there is no need to copy
+		the args and we can directly call the python interpreter with
+		the original args.
+		*/
+		return Py_Main(argc, argv);
+	}
+
+	/*
+	Start assembling the args for the Python interpreter call. We put the
+	name of our exe (argv[0]) in the position where the python.exe
+	canonically is, and insert the pyscript next.
+	*/
+	pyargv = malloc((argc + 5) * sizeof(char*));
+	if (pyargv == NULL) {
+		err = "not enough memory";
+		goto bail;
+	}
+	n = 0;
+	pyargv[n++] = argv[0];
+	pyargv[n++] = pyscript;
+
+	/* copy remaining args from the command line */
+	for (i = 1; i < argc; i++)
+		pyargv[n++] = argv[i];
+	/* argv[argc] is guaranteed to be NULL, so we forward that guarantee */
+	pyargv[n] = NULL;
+
+	ret = Py_Main(n, pyargv); /* The Python interpreter call */
+
+	free(pyargv);
+	return ret;
+
+bail:
+	fprintf(stderr, "abort: %s\n", err);
+	return 255;
+}