Update file handling

Author: mdboom

src/face.c

@@ -36,7 +36,6 @@ either expressed or implied, of the FreeBSD Project.
 #include "charmap.h"
 #include "constants.h"
 #include "encoding.h"
-#include "file.h"
 #include "glyph.h"
 #include "sfntnames.h"
 #include "size.h"
@@ -71,26 +70,18 @@ ftpy_ConstantType Py_FT_KERNING_ConstantType;
 */
 
 
-typedef struct
-{
-    PyObject *py_file;
-    FILE *fp;
-    int close_file;
-} py_file_def;
-
-
 static unsigned long read_from_file_callback(
     FT_Stream stream, unsigned long offset, unsigned char *buffer,
     unsigned long count) {
 
-    py_file_def *def = (py_file_def *)stream->descriptor.pointer;
+    Py_Face *self = (Py_Face *)stream->descriptor.pointer;
 
-    if (fseek(def->fp, offset, SEEK_SET) == -1) {
+    if (ftpy_fseek(self->fp, offset, SEEK_SET) == -1) {
         return 0;
     }
 
     if (count > 0) {
-        return fread(buffer, 1, count, def->fp);
+        return fread(buffer, 1, count, self->fp);
     }
 
     return 0;
@@ -99,15 +90,16 @@ static unsigned long read_from_file_callback(
 
 static void close_file_callback(FT_Stream stream)
 {
-    py_file_def *def = (py_file_def *)stream->descriptor.pointer;
+    Py_Face *self = (Py_Face *)stream->descriptor.pointer;
 
-    ftpy_PyFile_DupClose(def->py_file, def->fp);
+    ftpy_PyFile_DupClose(self->py_file, self->fp, self->offset);
 
-    if (def->close_file) {
-        ftpy_PyFile_CloseFile(def->py_file);
+    if (self->close_file) {
+        ftpy_PyFile_CloseFile(self->py_file);
     }
 
-    Py_DECREF(def->py_file);
+    Py_DECREF(self->py_file);
+    self->py_file = NULL;
 }
 
 
@@ -127,10 +119,10 @@ static int _py_file_to_open_args(
     PyObject *data = NULL;
     char *data_ptr;
     Py_ssize_t data_len;
-    py_file_def *stream_info = NULL;
     long file_size;
     void *new_memory;
     PyObject *read_string = NULL;
+    ftpy_offset_t offset;
 
     int result = -1;
 
@@ -146,25 +138,20 @@ static int _py_file_to_open_args(
         py_file = py_file_arg;
     }
 
-    if ((fp = ftpy_PyFile_Dup(py_file, (char *)"rb"))) {
-        stream_info = PyMem_Malloc(sizeof(py_file_def));
-        if (stream_info == NULL) {
-            goto exit;
-        }
-        memset(stream_info, 0, sizeof(py_file_def));
-
+    if ((fp = ftpy_PyFile_Dup(py_file, (char *)"rb", &offset))) {
         Py_INCREF(py_file);
-        stream_info->py_file = py_file;
-        stream_info->close_file = close_file;
-        stream_info->fp = fp;
+        face->py_file = py_file;
+        face->close_file = close_file;
+        face->fp = fp;
+        face->offset = offset;
         fseek(fp, 0, SEEK_END);
-        file_size = ftell(fp);
+        file_size = ftpy_ftell(fp);
         fseek(fp, 0, SEEK_SET);
 
         face->stream.base = NULL;
         face->stream.size = (unsigned long)file_size;
         face->stream.pos = 0;
-        face->stream.descriptor.pointer = stream_info;
+        face->stream.descriptor.pointer = face;
         face->stream.read = &read_from_file_callback;
         face->stream.close = &close_file_callback;
 
@@ -236,7 +223,10 @@ static int _py_file_to_open_args(
 static void
 Py_Face_dealloc(Py_Face* self)
 {
-    FT_Done_Face(self->x);
+    if (self->x) {
+        FT_Done_Face(self->x);
+    }
+    Py_XDECREF(self->py_file);
     Py_XDECREF(self->filename);
     free(self->mem);
     Py_TYPE(self)->tp_clear((PyObject*)self);

src/face.h

@@ -32,6 +32,7 @@ either expressed or implied, of the FreeBSD Project.
 
 #include "freetypy.h"
 #include "constants.h"
+#include "file.h"
 
 
 typedef struct {
@@ -42,6 +43,12 @@ typedef struct {
     size_t mem_size;
     PyObject *filename;
     int load_flags;
+
+    /* For stream reading */
+    PyObject *py_file;
+    FILE *fp;
+    int close_file;
+    ftpy_offset_t offset;
 } Py_Face;
 
 

src/file.c

@@ -44,14 +44,14 @@ either expressed or implied, of the FreeBSD Project.
 /*
  * Get a FILE* handle to the file represented by the Python object
  */
-FILE *ftpy_PyFile_Dup(PyObject *file, char *mode)
+FILE *ftpy_PyFile_Dup(PyObject *file, char *mode, ftpy_offset_t *orig_pos)
 {
     int fd, fd2;
     PyObject *ret, *os;
     Py_ssize_t pos;
     FILE *handle;
     /* Flush first to ensure things end up in the file in the correct order */
-    ret = PyObject_CallMethod(file, "flush", "");
+    ret = PyObject_CallMethod(file, (char *)"flush", (char *)"");
     if (ret == NULL) {
         return NULL;
     }
@@ -60,17 +60,22 @@ FILE *ftpy_PyFile_Dup(PyObject *file, char *mode)
     if (fd == -1) {
         return NULL;
     }
+
+    /* The handle needs to be dup'd because we have to call fclose
+       at the end */
     os = PyImport_ImportModule("os");
     if (os == NULL) {
         return NULL;
     }
-    ret = PyObject_CallMethod(os, "dup", "i", fd);
+    ret = PyObject_CallMethod(os, (char *)"dup", (char *)"i", fd);
     Py_DECREF(os);
     if (ret == NULL) {
         return NULL;
     }
     fd2 = PyNumber_AsSsize_t(ret, NULL);
     Py_DECREF(ret);
+
+/* Convert to FILE* handle */
 #ifdef _WIN32
     handle = _fdopen(fd2, mode);
 #else
@@ -80,7 +85,16 @@ FILE *ftpy_PyFile_Dup(PyObject *file, char *mode)
         PyErr_SetString(PyExc_IOError,
                         "Getting a FILE* from a Python file object failed");
     }
-    ret = PyObject_CallMethod(file, "tell", "");
+
+    /* Record the original raw file handle position */
+    *orig_pos = ftpy_ftell(handle);
+    if (*orig_pos == -1) {
+        // handle is a stream, so we don't have to worry about this
+        return handle;
+    }
+
+    /* Seek raw handle to the Python-side position */
+    ret = PyObject_CallMethod(file, (char *)"tell", (char *)"");
     if (ret == NULL) {
         fclose(handle);
         return NULL;
@@ -91,25 +105,48 @@ FILE *ftpy_PyFile_Dup(PyObject *file, char *mode)
         fclose(handle);
         return NULL;
     }
-    fseek(handle, pos, SEEK_SET);
+
+    if (ftpy_fseek(handle, pos, SEEK_SET) == -1) {
+        PyErr_SetString(PyExc_IOError, "seeking file failed");
+        return NULL;
+    }
+
     return handle;
 }
 
 /*
  * Close the dup-ed file handle, and seek the Python one to the current position
  */
-int ftpy_PyFile_DupClose(PyObject *file, FILE* handle)
+int ftpy_PyFile_DupClose(PyObject *file, FILE* handle, ftpy_offset_t orig_pos)
 {
+    int fd;
     PyObject *ret;
     Py_ssize_t position;
-    position = ftell(handle);
+
+    position = ftpy_ftell(handle);
     fclose(handle);
 
-    ret = PyObject_CallMethod(file, "seek", "ni", position, 0);
-    if (ret == NULL) {
+    /* Restore original file handle position, in order to not confuse
+       Python-side data structures */
+    fd = PyObject_AsFileDescriptor(file);
+    if (fd == -1) {
         return -1;
     }
-    Py_DECREF(ret);
+
+    if (ftpy_lseek(fd, orig_pos, SEEK_SET) != -1) {
+        if (position == -1) {
+            PyErr_SetString(PyExc_IOError, "obtaining file position failed");
+            return -1;
+        }
+
+        /* Seek Python-side handle to the FILE* handle position */
+        ret = PyObject_CallMethod(file, (char *)"seek", (char *)(FTPY_OFF_T_PYFMT "i"), position, 0);
+        if (ret == NULL) {
+            return -1;
+        }
+        Py_DECREF(ret);
+    }
+
     return 0;
 }
 
@@ -128,16 +165,22 @@ int ftpy_PyFile_Check(PyObject *file)
 
 /* Python 2.x */
 
-FILE* ftpy_PyFile_Dup(PyObject *file, char *mode)
+FILE* ftpy_PyFile_Dup(PyObject *file, char *mode, ftpy_offset_t *orig_pos)
 {
     return PyFile_AsFile(file);
 }
 
-int ftpy_PyFile_DupClose(PyObject *file, FILE* handle)
+int ftpy_PyFile_DupClose(PyObject *file, FILE* handle, ftpy_offset_t orig_pos)
 {
+    // deliberately nothing
     return 0;
 }
 
+int ftpy_PyFile_Check(PyObject *file)
+{
+    return PyFile_Check(file);
+}
+
 #endif
 
 PyObject* ftpy_PyFile_OpenFile(PyObject *filename, const char *mode)

src/file.h

@@ -34,8 +34,46 @@ either expressed or implied, of the FreeBSD Project.
 
 #include <stdio.h>
 
-FILE* ftpy_PyFile_Dup(PyObject *file, char *mode);
-int ftpy_PyFile_DupClose(PyObject *file, FILE* handle);
+#ifdef __cplusplus
+extern "C" {
+#endif
+#if defined(_MSC_VER) && defined(_WIN64) && (_MSC_VER > 1400)
+    #include <io.h>
+    #define ftpy_offset_t npy_int64
+    #define ftpy_fseek _fseeki64
+    #define ftpy_ftell _ftelli64
+    #define ftpy_lseek _lseeki64
+
+    #if NPY_SIZEOF_INT == 8
+        #define FTPY_OFF_T_PYFMT "i"
+    #elif NPY_SIZEOF_LONG == 8
+        #define FTPY_OFF_T_PYFMT "l"
+    #elif NPY_SIZEOF_LONGLONG == 8
+        #define FTPY_OFF_T_PYFMT "L"
+    #else
+        #error Unsupported size for type off_t
+    #endif
+#else
+    #define ftpy_fseek fseek
+    #define ftpy_ftell ftell
+    #define ftpy_lseek lseek
+    #define ftpy_offset_t off_t
+
+    #if NPY_SIZEOF_INT == NPY_SIZEOF_SHORT
+        #define FTPY_OFF_T_PYFMT "h"
+    #elif NPY_SIZEOF_INT == NPY_SIZEOF_INT
+        #define FTPY_OFF_T_PYFMT "i"
+    #elif NPY_SIZEOF_INT == NPY_SIZEOF_LONG
+        #define FTPY_OFF_T_PYFMT "l"
+    #elif NPY_SIZEOF_INT == NPY_SIZEOF_LONGLONG
+        #define FTPY_OFF_T_PYFMT "L"
+    #else
+        #error Unsupported size for type off_t
+    #endif
+#endif
+
+FILE* ftpy_PyFile_Dup(PyObject *file, char *mode, ftpy_offset_t *orig_pos);
+int ftpy_PyFile_DupClose(PyObject *file, FILE* handle, ftpy_offset_t orig_pos);
 int ftpy_PyFile_Check(PyObject *file);
 PyObject* ftpy_PyFile_OpenFile(PyObject *filename, const char *mode);
 int ftpy_PyFile_CloseFile(PyObject *file);