The Tor Browser: media/libpng/pngrio.c@97036ab72558

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     2 /* pngrio.c - functions for data input

     3  *

     4  * Last changed in libpng 1.6.9 [February 6, 2014]

     5  * Copyright (c) 1998-2014 Glenn Randers-Pehrson

     6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

     7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

     8  *

     9  * This code is released under the libpng license.

    10  * For conditions of distribution and use, see the disclaimer

    11  * and license in png.h

    12  *

    13  * This file provides a location for all input.  Users who need

    14  * special handling are expected to write a function that has the same

    15  * arguments as this and performs a similar function, but that possibly

    16  * has a different input method.  Note that you shouldn't change this

    17  * function, but rather write a replacement function and then make

    18  * libpng use it at run time with png_set_read_fn(...).

    19  */

    21 #include "pngpriv.h"

    23 #ifdef PNG_READ_SUPPORTED

    25 /* Read the data from whatever input you are using.  The default routine

    26  * reads from a file pointer.  Note that this routine sometimes gets called

    27  * with very small lengths, so you should implement some kind of simple

    28  * buffering if you are using unbuffered reads.  This should never be asked

    29  * to read more then 64K on a 16 bit machine.

    30  */

    31 void /* PRIVATE */

    32 png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length)

    33 {

    34    png_debug1(4, "reading %d bytes", (int)length);

    36    if (png_ptr->read_data_fn != NULL)

    37       (*(png_ptr->read_data_fn))(png_ptr, data, length);

    39    else

    40       png_error(png_ptr, "Call to NULL read function");

    41 }

    43 #ifdef PNG_STDIO_SUPPORTED

    44 /* This is the function that does the actual reading of data.  If you are

    45  * not reading from a standard C stream, you should create a replacement

    46  * read_data function and use it at run time with png_set_read_fn(), rather

    47  * than changing the library.

    48  */

    49 void PNGCBAPI

    50 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)

    51 {

    52    png_size_t check;

    54    if (png_ptr == NULL)

    55       return;

    57    /* fread() returns 0 on error, so it is OK to store this in a png_size_t

    58     * instead of an int, which is what fread() actually returns.

    59     */

    60    check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr));

    62    if (check != length)

    63       png_error(png_ptr, "Read Error");

    64 }

    65 #endif

    67 /* This function allows the application to supply a new input function

    68  * for libpng if standard C streams aren't being used.

    69  *

    70  * This function takes as its arguments:

    71  *

    72  * png_ptr      - pointer to a png input data structure

    73  *

    74  * io_ptr       - pointer to user supplied structure containing info about

    75  *                the input functions.  May be NULL.

    76  *

    77  * read_data_fn - pointer to a new input function that takes as its

    78  *                arguments a pointer to a png_struct, a pointer to

    79  *                a location where input data can be stored, and a 32-bit

    80  *                unsigned int that is the number of bytes to be read.

    81  *                To exit and output any fatal error messages the new write

    82  *                function should call png_error(png_ptr, "Error msg").

    83  *                May be NULL, in which case libpng's default function will

    84  *                be used.

    85  */

    86 void PNGAPI

    87 png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr,

    88    png_rw_ptr read_data_fn)

    89 {

    90    if (png_ptr == NULL)

    91       return;

    93    png_ptr->io_ptr = io_ptr;

    95 #ifdef PNG_STDIO_SUPPORTED

    96    if (read_data_fn != NULL)

    97       png_ptr->read_data_fn = read_data_fn;

    99    else

   100       png_ptr->read_data_fn = png_default_read_data;

   101 #else

   102    png_ptr->read_data_fn = read_data_fn;

   103 #endif

   105 #ifdef PNG_WRITE_SUPPORTED

   106    /* It is an error to write to a read device */

   107    if (png_ptr->write_data_fn != NULL)

   108    {

   109       png_ptr->write_data_fn = NULL;

   110       png_warning(png_ptr,

   111           "Can't set both read_data_fn and write_data_fn in the"

   112           " same structure");

   113    }

   114 #endif

   116 #ifdef PNG_WRITE_FLUSH_SUPPORTED

   117    png_ptr->output_flush_fn = NULL;

   118 #endif

   119 }

   120 #endif /* PNG_READ_SUPPORTED */

The Tor Browser / file revision

media/libpng/pngrio.c@97036ab72558

media/libpng/pngrio.c