Create fileutils.c/.h

 * _Py_fopen() and _Py_stat() come from Python/import.c
 * (_Py)_wrealpath() comes from Python/sysmodule.c
 * _Py_char2wchar(), _Py_wchar2char() and _Py_wfopen() come from Modules/main.c
 * (_Py)_wstat(), (_Py)_wgetcwd(), _Py_wreadlink() come from Modules/getpath.c

1 files changed, 758 insertions, 0 deletions

diff --git a/Python/fileutils.c b/Python/fileutils.c
new file mode 100644
index 0000000..ad8b840
--- /dev/null
+++ b/Python/fileutils.c
@@ -0,0 +1,758 @@
+#include "Python.h"
+
+#ifdef HAVE_STAT
+
+/* Decode a byte string from the locale encoding with the
+   surrogateescape error handler (undecodable bytes are decoded as characters
+   in range U+DC80..U+DCFF). If a byte sequence can be decoded as a surrogate
+   character, escape the bytes using the surrogateescape error handler instead
+   of decoding them.
+
+   Use _Py_wchar2char() to encode the character string back to a byte string.
+
+   Return a pointer to a newly allocated (wide) character string (use
+   PyMem_Free() to free the memory), or NULL on error (conversion error or
+   memory error). */
+wchar_t*
+_Py_char2wchar(char* arg)
+{
+    wchar_t *res;
+#ifdef HAVE_BROKEN_MBSTOWCS
+    /* Some platforms have a broken implementation of
+     * mbstowcs which does not count the characters that
+     * would result from conversion.  Use an upper bound.
+     */
+    size_t argsize = strlen(arg);
+#else
+    size_t argsize = mbstowcs(NULL, arg, 0);
+#endif
+    size_t count;
+    unsigned char *in;
+    wchar_t *out;
+#ifdef HAVE_MBRTOWC
+    mbstate_t mbs;
+#endif
+    if (argsize != (size_t)-1) {
+        res = (wchar_t *)PyMem_Malloc((argsize+1)*sizeof(wchar_t));
+        if (!res)
+            goto oom;
+        count = mbstowcs(res, arg, argsize+1);
+        if (count != (size_t)-1) {
+            wchar_t *tmp;
+            /* Only use the result if it contains no
+               surrogate characters. */
+            for (tmp = res; *tmp != 0 &&
+                         (*tmp < 0xd800 || *tmp > 0xdfff); tmp++)
+                ;
+            if (*tmp == 0)
+                return res;
+        }
+        PyMem_Free(res);
+    }
+    /* Conversion failed. Fall back to escaping with surrogateescape. */
+#ifdef HAVE_MBRTOWC
+    /* Try conversion with mbrtwoc (C99), and escape non-decodable bytes. */
+
+    /* Overallocate; as multi-byte characters are in the argument, the
+       actual output could use less memory. */
+    argsize = strlen(arg) + 1;
+    res = (wchar_t*)PyMem_Malloc(argsize*sizeof(wchar_t));
+    if (!res) goto oom;
+    in = (unsigned char*)arg;
+    out = res;
+    memset(&mbs, 0, sizeof mbs);
+    while (argsize) {
+        size_t converted = mbrtowc(out, (char*)in, argsize, &mbs);
+        if (converted == 0)
+            /* Reached end of string; null char stored. */
+            break;
+        if (converted == (size_t)-2) {
+            /* Incomplete character. This should never happen,
+               since we provide everything that we have -
+               unless there is a bug in the C library, or I
+               misunderstood how mbrtowc works. */
+            fprintf(stderr, "unexpected mbrtowc result -2\n");
+            return NULL;
+        }
+        if (converted == (size_t)-1) {
+            /* Conversion error. Escape as UTF-8b, and start over
+               in the initial shift state. */
+            *out++ = 0xdc00 + *in++;
+            argsize--;
+            memset(&mbs, 0, sizeof mbs);
+            continue;
+        }
+        if (*out >= 0xd800 && *out <= 0xdfff) {
+            /* Surrogate character.  Escape the original
+               byte sequence with surrogateescape. */
+            argsize -= converted;
+            while (converted--)
+                *out++ = 0xdc00 + *in++;
+            continue;
+        }
+        /* successfully converted some bytes */
+        in += converted;
+        argsize -= converted;
+        out++;
+    }
+#else
+    /* Cannot use C locale for escaping; manually escape as if charset
+       is ASCII (i.e. escape all bytes > 128. This will still roundtrip
+       correctly in the locale's charset, which must be an ASCII superset. */
+    res = PyMem_Malloc((strlen(arg)+1)*sizeof(wchar_t));
+    if (!res) goto oom;
+    in = (unsigned char*)arg;
+    out = res;
+    while(*in)
+        if(*in < 128)
+            *out++ = *in++;
+        else
+            *out++ = 0xdc00 + *in++;
+    *out = 0;
+#endif
+    return res;
+oom:
+    fprintf(stderr, "out of memory\n");
+    return NULL;
+}
+
+/* Encode a (wide) character string to the locale encoding with the
+   surrogateescape error handler (characters in range U+DC80..U+DCFF are
+   converted to bytes 0x80..0xFF).
+
+   This function is the reverse of _Py_char2wchar().
+
+   Return a pointer to a newly allocated byte string (use PyMem_Free() to free
+   the memory), or NULL on error (conversion error or memory error). */
+char*
+_Py_wchar2char(const wchar_t *text)
+{
+    const size_t len = wcslen(text);
+    char *result = NULL, *bytes = NULL;
+    size_t i, size, converted;
+    wchar_t c, buf[2];
+
+    /* The function works in two steps:
+       1. compute the length of the output buffer in bytes (size)
+       2. outputs the bytes */
+    size = 0;
+    buf[1] = 0;
+    while (1) {
+        for (i=0; i < len; i++) {
+            c = text[i];
+            if (c >= 0xdc80 && c <= 0xdcff) {
+                /* UTF-8b surrogate */
+                if (bytes != NULL) {
+                    *bytes++ = c - 0xdc00;
+                    size--;
+                }
+                else
+                    size++;
+                continue;
+            }
+            else {
+                buf[0] = c;
+                if (bytes != NULL)
+                    converted = wcstombs(bytes, buf, size);
+                else
+                    converted = wcstombs(NULL, buf, 0);
+                if (converted == (size_t)-1) {
+                    if (result != NULL)
+                        PyMem_Free(result);
+                    return NULL;
+                }
+                if (bytes != NULL) {
+                    bytes += converted;
+                    size -= converted;
+                }
+                else
+                    size += converted;
+            }
+        }
+        if (result != NULL) {
+            *bytes = 0;
+            break;
+        }
+
+        size += 1; /* nul byte at the end */
+        result = PyMem_Malloc(size);
+        if (result == NULL)
+            return NULL;
+        bytes = result;
+    }
+    return result;
+}
+
+#if defined(MS_WINDOWS) || defined(HAVE_STAT)
+int
+_Py_wstat(const wchar_t* path, struct stat *buf)
+{
+/* In principle, this should use HAVE__WSTAT, and _wstat
+   should be detected by autoconf. However, no current
+   POSIX system provides that function, so testing for
+   it is pointless.
+   Not sure whether the MS_WINDOWS guards are necessary:
+   perhaps for cygwin/mingw builds?
+*/
+#ifdef MS_WINDOWS
+    return _wstat(path, buf);
+#else
+    int err;
+    char *fname;
+    fname = _Py_wchar2char(path);
+    if (fname == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+    err = stat(fname, buf);
+    PyMem_Free(fname);
+    return err;
+#endif
+}
+#endif
+
+/* Call _wstat() on Windows, or stat() otherwise. Only fill st_mode
+   attribute on Windows. Return 0 on success, -1 on stat error or (if
+   PyErr_Occurred()) unicode error. */
+
+int
+_Py_stat(PyObject *unicode, struct stat *statbuf)
+{
+#ifdef MS_WINDOWS
+    wchar_t *path;
+    int err;
+    struct _stat wstatbuf;
+
+    path = PyUnicode_AsWideCharString(unicode, NULL);
+    if (path == NULL)
+        return -1;
+    err = _wstat(path, &wstatbuf);
+    PyMem_Free(path);
+    if (!err)
+        statbuf->st_mode = wstatbuf.st_mode;
+    return err;
+#else
+    int ret;
+    PyObject *bytes = PyUnicode_EncodeFSDefault(unicode);
+    if (bytes == NULL)
+        return -1;
+    ret = stat(PyBytes_AS_STRING(bytes), statbuf);
+    Py_DECREF(bytes);
+    return ret;
+#endif
+}
+
+FILE *
+_Py_wfopen(const wchar_t *path, const wchar_t *mode)
+{
+#ifndef MS_WINDOWS
+    FILE *f;
+    char *cpath;
+    char cmode[10];
+    size_t r;
+    r = wcstombs(cmode, mode, 10);
+    if (r == (size_t)-1 || r >= 10) {
+        errno = EINVAL;
+        return NULL;
+    }
+    cpath = _Py_wchar2char(path);
+    if (cpath == NULL)
+        return NULL;
+    f = fopen(cpath, cmode);
+    PyMem_Free(cpath);
+    return f;
+#else
+    return _wfopen(path, mode);
+#endif
+}
+
+/* Call _wfopen() on Windows, or fopen() otherwise. Return the new file
+   object on success, or NULL if the file cannot be open or (if
+   PyErr_Occurred()) on unicode error */
+
+FILE*
+_Py_fopen(PyObject *unicode, const char *mode)
+{
+#ifdef MS_WINDOWS
+    wchar_t *path;
+    wchar_t wmode[10];
+    int usize;
+    FILE *f;
+
+    usize = MultiByteToWideChar(CP_ACP, 0, mode, -1, wmode, sizeof(wmode));
+    if (usize == 0)
+        return NULL;
+
+    path = PyUnicode_AsWideCharString(unicode, NULL);
+    if (path == NULL)
+        return NULL;
+    f = _wfopen(path, wmode);
+    PyMem_Free(path);
+    return f;
+#else
+    FILE *f;
+    PyObject *bytes = PyUnicode_EncodeFSDefault(unicode);
+    if (bytes == NULL)
+        return NULL;
+    f = fopen(PyBytes_AS_STRING(bytes), mode);
+    Py_DECREF(bytes);
+    return f;
+#endif
+}
+
+#ifdef HAVE_READLINK
+int
+_Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t bufsiz)
+{
+    char *cpath;
+    char cbuf[PATH_MAX];
+    int res;
+    size_t r1;
+
+    cpath = _Py_wchar2char(path);
+    if (cpath == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+    res = (int)readlink(cpath, cbuf, PATH_MAX);
+    PyMem_Free(cpath);
+    if (res == -1)
+        return -1;
+    if (res == PATH_MAX) {
+        errno = EINVAL;
+        return -1;
+    }
+    cbuf[res] = '\0'; /* buf will be null terminated */
+    r1 = mbstowcs(buf, cbuf, bufsiz);
+    if (r1 == -1) {
+        errno = EINVAL;
+        return -1;
+    }
+    return (int)r1;
+}
+#endif
+
+#ifdef HAVE_REALPATH
+wchar_t*
+_Py_wrealpath(const wchar_t *path, wchar_t *resolved_path)
+{
+    char *cpath;
+    char cresolved_path[PATH_MAX];
+    char *res;
+    size_t r;
+    cpath = _Py_wchar2char(path);
+    if (cpath == NULL) {
+        errno = EINVAL;
+        return NULL;
+    }
+    res = realpath(cpath, cresolved_path);
+    PyMem_Free(cpath);
+    if (res == NULL)
+        return NULL;
+    r = mbstowcs(resolved_path, cresolved_path, PATH_MAX);
+    if (r == (size_t)-1 || r >= PATH_MAX) {
+        errno = EINVAL;
+        return NULL;
+    }
+    return resolved_path;
+}
+#endif
+
+wchar_t*
+_Py_wgetcwd(wchar_t *buf, size_t size)
+{
+#ifdef MS_WINDOWS
+    return _wgetcwd(buf, size);
+#else
+    char fname[PATH_MAX];
+    if (getcwd(fname, PATH_MAX) == NULL)
+        return NULL;
+    if (mbstowcs(buf, fname, size) >= size) {
+        errno = ERANGE;
+        return NULL;
+    }
+    return buf;
+#endif
+}
+
+#endif
+
+#include "Python.h"
+
+#ifdef HAVE_STAT
+
+/* Decode a byte string from the locale encoding with the
+   surrogateescape error handler (undecodable bytes are decoded as characters
+   in range U+DC80..U+DCFF). If a byte sequence can be decoded as a surrogate
+   character, escape the bytes using the surrogateescape error handler instead
+   of decoding them.
+
+   Use _Py_wchar2char() to encode the character string back to a byte string.
+
+   Return a pointer to a newly allocated (wide) character string (use
+   PyMem_Free() to free the memory), or NULL on error (conversion error or
+   memory error). */
+wchar_t*
+_Py_char2wchar(char* arg)
+{
+    wchar_t *res;
+#ifdef HAVE_BROKEN_MBSTOWCS
+    /* Some platforms have a broken implementation of
+     * mbstowcs which does not count the characters that
+     * would result from conversion.  Use an upper bound.
+     */
+    size_t argsize = strlen(arg);
+#else
+    size_t argsize = mbstowcs(NULL, arg, 0);
+#endif
+    size_t count;
+    unsigned char *in;
+    wchar_t *out;
+#ifdef HAVE_MBRTOWC
+    mbstate_t mbs;
+#endif
+    if (argsize != (size_t)-1) {
+        res = (wchar_t *)PyMem_Malloc((argsize+1)*sizeof(wchar_t));
+        if (!res)
+            goto oom;
+        count = mbstowcs(res, arg, argsize+1);
+        if (count != (size_t)-1) {
+            wchar_t *tmp;
+            /* Only use the result if it contains no
+               surrogate characters. */
+            for (tmp = res; *tmp != 0 &&
+                         (*tmp < 0xd800 || *tmp > 0xdfff); tmp++)
+                ;
+            if (*tmp == 0)
+                return res;
+        }
+        PyMem_Free(res);
+    }
+    /* Conversion failed. Fall back to escaping with surrogateescape. */
+#ifdef HAVE_MBRTOWC
+    /* Try conversion with mbrtwoc (C99), and escape non-decodable bytes. */
+
+    /* Overallocate; as multi-byte characters are in the argument, the
+       actual output could use less memory. */
+    argsize = strlen(arg) + 1;
+    res = (wchar_t*)PyMem_Malloc(argsize*sizeof(wchar_t));
+    if (!res) goto oom;
+    in = (unsigned char*)arg;
+    out = res;
+    memset(&mbs, 0, sizeof mbs);
+    while (argsize) {
+        size_t converted = mbrtowc(out, (char*)in, argsize, &mbs);
+        if (converted == 0)
+            /* Reached end of string; null char stored. */
+            break;
+        if (converted == (size_t)-2) {
+            /* Incomplete character. This should never happen,
+               since we provide everything that we have -
+               unless there is a bug in the C library, or I
+               misunderstood how mbrtowc works. */
+            fprintf(stderr, "unexpected mbrtowc result -2\n");
+            return NULL;
+        }
+        if (converted == (size_t)-1) {
+            /* Conversion error. Escape as UTF-8b, and start over
+               in the initial shift state. */
+            *out++ = 0xdc00 + *in++;
+            argsize--;
+            memset(&mbs, 0, sizeof mbs);
+            continue;
+        }
+        if (*out >= 0xd800 && *out <= 0xdfff) {
+            /* Surrogate character.  Escape the original
+               byte sequence with surrogateescape. */
+            argsize -= converted;
+            while (converted--)
+                *out++ = 0xdc00 + *in++;
+            continue;
+        }
+        /* successfully converted some bytes */
+        in += converted;
+        argsize -= converted;
+        out++;
+    }
+#else
+    /* Cannot use C locale for escaping; manually escape as if charset
+       is ASCII (i.e. escape all bytes > 128. This will still roundtrip
+       correctly in the locale's charset, which must be an ASCII superset. */
+    res = PyMem_Malloc((strlen(arg)+1)*sizeof(wchar_t));
+    if (!res) goto oom;
+    in = (unsigned char*)arg;
+    out = res;
+    while(*in)
+        if(*in < 128)
+            *out++ = *in++;
+        else
+            *out++ = 0xdc00 + *in++;
+    *out = 0;
+#endif
+    return res;
+oom:
+    fprintf(stderr, "out of memory\n");
+    return NULL;
+}
+
+/* Encode a (wide) character string to the locale encoding with the
+   surrogateescape error handler (characters in range U+DC80..U+DCFF are
+   converted to bytes 0x80..0xFF).
+
+   This function is the reverse of _Py_char2wchar().
+
+   Return a pointer to a newly allocated byte string (use PyMem_Free() to free
+   the memory), or NULL on error (conversion error or memory error). */
+char*
+_Py_wchar2char(const wchar_t *text)
+{
+    const size_t len = wcslen(text);
+    char *result = NULL, *bytes = NULL;
+    size_t i, size, converted;
+    wchar_t c, buf[2];
+
+    /* The function works in two steps:
+       1. compute the length of the output buffer in bytes (size)
+       2. outputs the bytes */
+    size = 0;
+    buf[1] = 0;
+    while (1) {
+        for (i=0; i < len; i++) {
+            c = text[i];
+            if (c >= 0xdc80 && c <= 0xdcff) {
+                /* UTF-8b surrogate */
+                if (bytes != NULL) {
+                    *bytes++ = c - 0xdc00;
+                    size--;
+                }
+                else
+                    size++;
+                continue;
+            }
+            else {
+                buf[0] = c;
+                if (bytes != NULL)
+                    converted = wcstombs(bytes, buf, size);
+                else
+                    converted = wcstombs(NULL, buf, 0);
+                if (converted == (size_t)-1) {
+                    if (result != NULL)
+                        PyMem_Free(result);
+                    return NULL;
+                }
+                if (bytes != NULL) {
+                    bytes += converted;
+                    size -= converted;
+                }
+                else
+                    size += converted;
+            }
+        }
+        if (result != NULL) {
+            *bytes = 0;
+            break;
+        }
+
+        size += 1; /* nul byte at the end */
+        result = PyMem_Malloc(size);
+        if (result == NULL)
+            return NULL;
+        bytes = result;
+    }
+    return result;
+}
+
+#if defined(MS_WINDOWS) || defined(HAVE_STAT)
+int
+_Py_wstat(const wchar_t* path, struct stat *buf)
+{
+/* In principle, this should use HAVE__WSTAT, and _wstat
+   should be detected by autoconf. However, no current
+   POSIX system provides that function, so testing for
+   it is pointless.
+   Not sure whether the MS_WINDOWS guards are necessary:
+   perhaps for cygwin/mingw builds?
+*/
+#ifdef MS_WINDOWS
+    return _wstat(path, buf);
+#else
+    int err;
+    char *fname;
+    fname = _Py_wchar2char(path);
+    if (fname == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+    err = stat(fname, buf);
+    PyMem_Free(fname);
+    return err;
+#endif
+}
+#endif
+
+/* Call _wstat() on Windows, or stat() otherwise. Only fill st_mode
+   attribute on Windows. Return 0 on success, -1 on stat error or (if
+   PyErr_Occurred()) unicode error. */
+
+int
+_Py_stat(PyObject *unicode, struct stat *statbuf)
+{
+#ifdef MS_WINDOWS
+    wchar_t *path;
+    int err;
+    struct _stat wstatbuf;
+
+    path = PyUnicode_AsWideCharString(unicode, NULL);
+    if (path == NULL)
+        return -1;
+    err = _wstat(path, &wstatbuf);
+    PyMem_Free(path);
+    if (!err)
+        statbuf->st_mode = wstatbuf.st_mode;
+    return err;
+#else
+    int ret;
+    PyObject *bytes = PyUnicode_EncodeFSDefault(unicode);
+    if (bytes == NULL)
+        return -1;
+    ret = stat(PyBytes_AS_STRING(bytes), statbuf);
+    Py_DECREF(bytes);
+    return ret;
+#endif
+}
+
+FILE *
+_Py_wfopen(const wchar_t *path, const wchar_t *mode)
+{
+#ifndef MS_WINDOWS
+    FILE *f;
+    char *cpath;
+    char cmode[10];
+    size_t r;
+    r = wcstombs(cmode, mode, 10);
+    if (r == (size_t)-1 || r >= 10) {
+        errno = EINVAL;
+        return NULL;
+    }
+    cpath = _Py_wchar2char(path);
+    if (cpath == NULL)
+        return NULL;
+    f = fopen(cpath, cmode);
+    PyMem_Free(cpath);
+    return f;
+#else
+    return _wfopen(path, mode);
+#endif
+}
+
+/* Call _wfopen() on Windows, or fopen() otherwise. Return the new file
+   object on success, or NULL if the file cannot be open or (if
+   PyErr_Occurred()) on unicode error */
+
+FILE*
+_Py_fopen(PyObject *unicode, const char *mode)
+{
+#ifdef MS_WINDOWS
+    wchar_t *path;
+    wchar_t wmode[10];
+    int usize;
+    FILE *f;
+
+    usize = MultiByteToWideChar(CP_ACP, 0, mode, -1, wmode, sizeof(wmode));
+    if (usize == 0)
+        return NULL;
+
+    path = PyUnicode_AsWideCharString(unicode, NULL);
+    if (path == NULL)
+        return NULL;
+    f = _wfopen(path, wmode);
+    PyMem_Free(path);
+    return f;
+#else
+    FILE *f;
+    PyObject *bytes = PyUnicode_EncodeFSDefault(unicode);
+    if (bytes == NULL)
+        return NULL;
+    f = fopen(PyBytes_AS_STRING(bytes), mode);
+    Py_DECREF(bytes);
+    return f;
+#endif
+}
+
+#ifdef HAVE_READLINK
+int
+_Py_wreadlink(const wchar_t *path, wchar_t *buf, size_t bufsiz)
+{
+    char *cpath;
+    char cbuf[PATH_MAX];
+    int res;
+    size_t r1;
+
+    cpath = _Py_wchar2char(path);
+    if (cpath == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+    res = (int)readlink(cpath, cbuf, PATH_MAX);
+    PyMem_Free(cpath);
+    if (res == -1)
+        return -1;
+    if (res == PATH_MAX) {
+        errno = EINVAL;
+        return -1;
+    }
+    cbuf[res] = '\0'; /* buf will be null terminated */
+    r1 = mbstowcs(buf, cbuf, bufsiz);
+    if (r1 == -1) {
+        errno = EINVAL;
+        return -1;
+    }
+    return (int)r1;
+}
+#endif
+
+#ifdef HAVE_REALPATH
+wchar_t*
+_Py_wrealpath(const wchar_t *path, wchar_t *resolved_path)
+{
+    char *cpath;
+    char cresolved_path[PATH_MAX];
+    char *res;
+    size_t r;
+    cpath = _Py_wchar2char(path);
+    if (cpath == NULL) {
+        errno = EINVAL;
+        return NULL;
+    }
+    res = realpath(cpath, cresolved_path);
+    PyMem_Free(cpath);
+    if (res == NULL)
+        return NULL;
+    r = mbstowcs(resolved_path, cresolved_path, PATH_MAX);
+    if (r == (size_t)-1 || r >= PATH_MAX) {
+        errno = EINVAL;
+        return NULL;
+    }
+    return resolved_path;
+}
+#endif
+
+wchar_t*
+_Py_wgetcwd(wchar_t *buf, size_t size)
+{
+#ifdef MS_WINDOWS
+    return _wgetcwd(buf, size);
+#else
+    char fname[PATH_MAX];
+    if (getcwd(fname, PATH_MAX) == NULL)
+        return NULL;
+    if (mbstowcs(buf, fname, size) >= size) {
+        errno = ERANGE;
+        return NULL;
+    }
+    return buf;
+#endif
+}
+
+#endif
+