pstcache.c

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/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Persistent Bitmap Cache routines
   Copyright (C) Jeroen Meijer <jeroen@oldambt7.com> 2004-2008

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "precomp.h"

#define MAX_CELL_SIZE       0x1000  /* pixels */

#define IS_PERSISTENT(id) (id < 8 && g_pstcache_fd[id] > 0)

extern int g_server_depth;
extern RD_BOOL g_bitmap_cache;
extern RD_BOOL g_bitmap_cache_persist_enable;
extern RD_BOOL g_bitmap_cache_precache;

int g_pstcache_fd[8];
int g_pstcache_Bpp;
RD_BOOL g_pstcache_enumerated = False;
uint8 zero_key[] = { 0, 0, 0, 0, 0, 0, 0, 0 };


/* Update mru stamp/index for a bitmap */
void
pstcache_touch_bitmap(uint8 cache_id, uint16 cache_idx, uint32 stamp)
{
    int fd;

    if (!IS_PERSISTENT(cache_id) || cache_idx >= BMPCACHE2_NUM_PSTCELLS)
        return;

    fd = g_pstcache_fd[cache_id];
    rd_lseek_file(fd, 12 + cache_idx * (g_pstcache_Bpp * MAX_CELL_SIZE + sizeof(CELLHEADER)));
    rd_write_file(fd, &stamp, sizeof(stamp));
}

/* Load a bitmap from the persistent cache */
RD_BOOL
pstcache_load_bitmap(uint8 cache_id, uint16 cache_idx)
{
    uint8 *celldata;
    int fd;
    CELLHEADER cellhdr;
    RD_HBITMAP bitmap;

    if (!g_bitmap_cache_persist_enable)
        return False;

    if (!IS_PERSISTENT(cache_id) || cache_idx >= BMPCACHE2_NUM_PSTCELLS)
        return False;

    fd = g_pstcache_fd[cache_id];
    rd_lseek_file(fd, cache_idx * (g_pstcache_Bpp * MAX_CELL_SIZE + sizeof(CELLHEADER)));
    rd_read_file(fd, &cellhdr, sizeof(CELLHEADER));
    celldata = (uint8 *) xmalloc(cellhdr.length);
    rd_read_file(fd, celldata, cellhdr.length);

    bitmap = ui_create_bitmap(cellhdr.width, cellhdr.height, celldata);
    DEBUG(("Load bitmap from disk: id=%d, idx=%d, bmp=%p)\n", cache_id, cache_idx, bitmap));
    cache_put_bitmap(cache_id, cache_idx, bitmap);

    xfree(celldata);
    return True;
}

/* Store a bitmap in the persistent cache */
RD_BOOL
pstcache_save_bitmap(uint8 cache_id, uint16 cache_idx, uint8 * key,
             uint8 width, uint8 height, uint16 length, uint8 * data)
{
    int fd;
    CELLHEADER cellhdr;

    if (!IS_PERSISTENT(cache_id) || cache_idx >= BMPCACHE2_NUM_PSTCELLS)
        return False;

    memcpy(cellhdr.key, key, sizeof(HASH_KEY));
    cellhdr.width = width;
    cellhdr.height = height;
    cellhdr.length = length;
    cellhdr.stamp = 0;

    fd = g_pstcache_fd[cache_id];
    rd_lseek_file(fd, cache_idx * (g_pstcache_Bpp * MAX_CELL_SIZE + sizeof(CELLHEADER)));
    rd_write_file(fd, &cellhdr, sizeof(CELLHEADER));
    rd_write_file(fd, data, length);

    return True;
}

/* List the bitmap keys from the persistent cache file */
int
pstcache_enumerate(uint8 id, HASH_KEY * keylist)
{
    int fd, n;
    uint16 idx;
    sint16 mru_idx[0xa00];
    uint32 mru_stamp[0xa00];
    CELLHEADER cellhdr;

    if (!(g_bitmap_cache && g_bitmap_cache_persist_enable && IS_PERSISTENT(id)))
        return 0;

    /* The server disconnects if the bitmap cache content is sent more than once */
    if (g_pstcache_enumerated)
        return 0;

    DEBUG_RDP5(("Persistent bitmap cache enumeration... "));
    for (idx = 0; idx < BMPCACHE2_NUM_PSTCELLS; idx++)
    {
        fd = g_pstcache_fd[id];
        rd_lseek_file(fd, idx * (g_pstcache_Bpp * MAX_CELL_SIZE + sizeof(CELLHEADER)));
        if (rd_read_file(fd, &cellhdr, sizeof(CELLHEADER)) <= 0)
            break;

        if (memcmp(cellhdr.key, zero_key, sizeof(HASH_KEY)) != 0)
        {
            memcpy(keylist[idx], cellhdr.key, sizeof(HASH_KEY));

            /* Pre-cache (not possible for 8 bit colour depth cause it needs a colourmap) */
            if (g_bitmap_cache_precache && cellhdr.stamp && g_server_depth > 8)
                pstcache_load_bitmap(id, idx);

            /* Sort by stamp */
            for (n = idx; n > 0 && cellhdr.stamp < mru_stamp[n - 1]; n--)
            {
                mru_idx[n] = mru_idx[n - 1];
                mru_stamp[n] = mru_stamp[n - 1];
            }

            mru_idx[n] = idx;
            mru_stamp[n] = cellhdr.stamp;
        }
        else
        {
            break;
        }
    }

    DEBUG_RDP5(("%d cached bitmaps.\n", idx));

    cache_rebuild_bmpcache_linked_list(id, mru_idx, idx);
    g_pstcache_enumerated = True;
    return idx;
}

/* initialise the persistent bitmap cache */
RD_BOOL
pstcache_init(uint8 cache_id)
{
    int fd;
    char filename[256];

    if (g_pstcache_enumerated)
        return True;

    g_pstcache_fd[cache_id] = 0;

    if (!(g_bitmap_cache && g_bitmap_cache_persist_enable))
        return False;

    if (!rd_pstcache_mkdir())
    {
        DEBUG(("failed to get/make cache directory!\n"));
        return False;
    }

    g_pstcache_Bpp = (g_server_depth + 7) / 8;
    sprintf(filename, "cache/pstcache_%d_%d", cache_id, g_pstcache_Bpp);
    DEBUG(("persistent bitmap cache file: %s\n", filename));

    fd = rd_open_file(filename);
    if (fd == -1)
        return False;

    if (!rd_lock_file(fd, 0, 0))
    {
        warning("Persistent bitmap caching is disabled. (The file is already in use)\n");
        rd_close_file(fd);
        return False;
    }

    g_pstcache_fd[cache_id] = fd;
    return True;
}