comparison mercurial/osutil.c @ 8330:7de68012f86e

Windows: improve performance via buffered I/O

The posixfile_nt code hits the win32 file API directly, which
essentially amounts to performing a system call for every read and
write. This is slow.

We add a C extension that lets us use a Python file object instead,
but preserve our desired POSIX-like semantics (the ability to rename
or delete a file that is being accessed).

If the C extension is not available (e.g. in a VPS environment
without a compiler), we fall back to the posixfile_nt code.

8329:79a12651d46b

 the GNU General Public License, incorporated herein by reference.
*/

#define _ATFILE_SOURCE
#include <Python.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <dirent.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#endif

#ifdef _WIN32
/*
stat struct compatible with hg expectations

	}

	return _listdir(path, plen, wantstat, skip);
}

static char osutil_doc[] = "Native operating system services.";

static PyMethodDef methods[] = {
	{"listdir", (PyCFunction)listdir, METH_VARARGS | METH_KEYWORDS,
	 "list a directory\n"},
	{NULL, NULL}
};

PyMODINIT_FUNC initosutil(void)
{

8330:7de68012f86e

 the GNU General Public License, incorporated herein by reference.
*/

#define _ATFILE_SOURCE
#include <Python.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>

#ifdef _WIN32
# include <windows.h>
# include <io.h>
#else
# include <dirent.h>
# include <sys/stat.h>
# include <sys/types.h>
# include <unistd.h>
#endif

#ifdef _WIN32
/*
stat struct compatible with hg expectations

	}

	return _listdir(path, plen, wantstat, skip);
}

#ifdef _WIN32
static PyObject *posixfile(PyObject *self, PyObject *args, PyObject *kwds)
{
	static char *kwlist[] = {"name", "mode", "buffering", NULL};
	PyObject *file_obj = NULL;
	char *name = NULL;
	char *mode = "rb";
	DWORD access;
	DWORD creation;
	HANDLE handle;
	int fd, flags = 0;
	int bufsize = -1;
	char m0, m1, m2;
	char fpmode[4];
	int fppos = 0;
	int plus;
	FILE *fp;

	if (!PyArg_ParseTupleAndKeywords(args, kwds, "et|si:posixfile", kwlist,
					 Py_FileSystemDefaultEncoding,
					 &name, &mode, &bufsize))
		return NULL;

	m0 = mode[0];
	m1 = m0 ? mode[1] : '\0';
	m2 = m1 ? mode[2] : '\0';
	plus = m1 == '+' || m2 == '+';

	fpmode[fppos++] = m0;
	if (m1 == 'b' || m2 == 'b') {
		flags = _O_BINARY;
		fpmode[fppos++] = 'b';
	}
	else
		flags = _O_TEXT;
	if (plus) {
		flags |= _O_RDWR;
		access = GENERIC_READ | GENERIC_WRITE;
		fpmode[fppos++] = '+';
	}
	fpmode[fppos++] = '\0';

	switch (m0) {
	case 'r':
		creation = OPEN_EXISTING;
		if (!plus) {
			flags |= _O_RDONLY;
			access = GENERIC_READ;
		}
		break;
	case 'w':
		creation = CREATE_ALWAYS;
		if (!plus) {
			access = GENERIC_WRITE;
			flags |= _O_WRONLY;
		}
		break;
	case 'a':
		creation = OPEN_ALWAYS;
		flags |= _O_APPEND;
		if (!plus) {
			flags |= _O_WRONLY;
			access = GENERIC_WRITE;
		}
		break;
	default:
		PyErr_Format(PyExc_ValueError,
			     "mode string must begin with one of 'r', 'w', "
			     "or 'a', not '%c'", m0);
		goto bail;
	}

	handle = CreateFile(name, access,
			    FILE_SHARE_READ | FILE_SHARE_WRITE |
			    FILE_SHARE_DELETE,
			    NULL,
			    creation,
			    FILE_ATTRIBUTE_NORMAL,
			    0);

	if (handle == INVALID_HANDLE_VALUE) {
		PyErr_SetFromWindowsErrWithFilename(GetLastError(), name);
		goto bail;
	}

	fd = _open_osfhandle((intptr_t) handle, flags);
	if (fd == -1) {
		CloseHandle(handle);
		PyErr_SetFromErrnoWithFilename(PyExc_IOError, name);
		goto bail;
	}

	fp = _fdopen(fd, fpmode);
	if (fp == NULL) {
		_close(fd);
		PyErr_SetFromErrnoWithFilename(PyExc_IOError, name);
		goto bail;
	}

	file_obj = PyFile_FromFile(fp, name, mode, fclose);
	if (file_obj == NULL) {
		fclose(fp);
		goto bail;
	}

	PyFile_SetBufSize(file_obj, bufsize);
bail:
	PyMem_Free(name);
	return file_obj;
}
#endif

static char osutil_doc[] = "Native operating system services.";

static PyMethodDef methods[] = {
	{"listdir", (PyCFunction)listdir, METH_VARARGS | METH_KEYWORDS,
	 "list a directory\n"},
#ifdef _WIN32
	{"posixfile", (PyCFunction)posixfile, METH_VARARGS | METH_KEYWORDS,
	 "Open a file with POSIX-like semantics.\n"
"On error, this function may raise either a WindowsError or an IOError."},
#endif
	{NULL, NULL}
};

PyMODINIT_FUNC initosutil(void)
{