/*****************************************************************************
 * cache.c: Plugins cache
 *****************************************************************************
 * Copyright (C) 2001-2007 VLC authors and VideoLAN
 * $Id: 5d9651fcf2ee1fb6c5a2fda272b740dc4c950952 $
 *
 * Authors: Sam Hocevar <sam@zoy.org>
 *          Ethan C. Baldridge <BaldridgeE@cadmus.com>
 *          Hans-Peter Jansen <hpj@urpla.net>
 *          Gildas Bazin <gbazin@videolan.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#   include <unistd.h>
#endif
#include <assert.h>

#include <vlc_common.h>
#include "libvlc.h"

#include <vlc_plugin.h>
#include <errno.h>

#include "config/configuration.h"

#include <vlc_fs.h>

#include "modules/modules.h"


/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
#ifdef HAVE_DYNAMIC_PLUGINS
/* Sub-version number
 * (only used to avoid breakage in dev version when cache structure changes) */
#define CACHE_SUBVERSION_NUM 22

/* Cache filename */
#define CACHE_NAME "plugins.dat"
/* Magic for the cache filename */
#define CACHE_STRING "cache "PACKAGE_NAME" "PACKAGE_VERSION


void CacheDelete( vlc_object_t *obj, const char *dir )
{
    char *path;

    assert( dir != NULL );

    if( asprintf( &path, "%s"DIR_SEP CACHE_NAME, dir ) == -1 )
        return;
    msg_Dbg( obj, "removing plugins cache file %s", path );
    vlc_unlink( path );
    free( path );
}

#define LOAD_IMMEDIATE(a) \
    if (fread (&(a), sizeof (char), sizeof (a), file) != sizeof (a)) \
        goto error
#define LOAD_FLAG(a) \
    do { \
        unsigned char b; \
        LOAD_IMMEDIATE(b); \
        if (b > 1) \
            goto error; \
        (a) = b; \
    } while (0)

static int CacheLoadString (char **p, FILE *file)
{
    char *psz = NULL;
    uint16_t size;

    LOAD_IMMEDIATE (size);
    if (size > 16384)
    {
error:
        return -1;
    }

    if (size > 0)
    {
        psz = malloc (size+1);
        if (unlikely(psz == NULL))
            goto error;
        if (fread (psz, 1, size, file) != size)
        {
            free (psz);
            goto error;
        }
        psz[size] = '\0';
    }
    *p = psz;
    return 0;
}

#define LOAD_STRING(a) \
    if (CacheLoadString (&(a), file)) goto error

static int CacheLoadConfig (module_config_t *cfg, FILE *file)
{
    LOAD_IMMEDIATE (cfg->i_type);
    LOAD_IMMEDIATE (cfg->i_short);
    LOAD_FLAG (cfg->b_advanced);
    LOAD_FLAG (cfg->b_internal);
    LOAD_FLAG (cfg->b_unsaveable);
    LOAD_FLAG (cfg->b_safe);
    LOAD_FLAG (cfg->b_removed);
    LOAD_STRING (cfg->psz_type);
    LOAD_STRING (cfg->psz_name);
    LOAD_STRING (cfg->psz_text);
    LOAD_STRING (cfg->psz_longtext);
    LOAD_IMMEDIATE (cfg->list_count);

    if (IsConfigStringType (cfg->i_type))
    {
        LOAD_STRING (cfg->orig.psz);
        if (cfg->orig.psz != NULL)
            cfg->value.psz = strdup (cfg->orig.psz);
        else
            cfg->value.psz = NULL;

        if (cfg->list_count)
            cfg->list.psz = xmalloc (cfg->list_count * sizeof (char *));
        else /* TODO: fix config_GetPszChoices() instead of this hack: */
            LOAD_IMMEDIATE(cfg->list.psz_cb);
        for (unsigned i = 0; i < cfg->list_count; i++)
        {
            LOAD_STRING (cfg->list.psz[i]);
            if (cfg->list.psz[i] == NULL /* NULL -> empty string */
             && (cfg->list.psz[i] = calloc (1, 1)) == NULL)
                goto error;
        }
    }
    else
    {
        LOAD_IMMEDIATE (cfg->orig);
        LOAD_IMMEDIATE (cfg->min);
        LOAD_IMMEDIATE (cfg->max);
        cfg->value = cfg->orig;

        if (cfg->list_count)
            cfg->list.i = xmalloc (cfg->list_count * sizeof (int));
        else /* TODO: fix config_GetPszChoices() instead of this hack: */
            LOAD_IMMEDIATE(cfg->list.i_cb);
        for (unsigned i = 0; i < cfg->list_count; i++)
             LOAD_IMMEDIATE (cfg->list.i[i]);
    }
    cfg->list_text = xmalloc (cfg->list_count * sizeof (char *));
    for (unsigned i = 0; i < cfg->list_count; i++)
    {
        LOAD_STRING (cfg->list_text[i]);
        if (cfg->list_text[i] == NULL /* NULL -> empty string */
         && (cfg->list_text[i] = calloc (1, 1)) == NULL)
            goto error;
    }

    return 0;
error:
    return -1; /* FIXME: leaks */
}

static int CacheLoadModuleConfig (module_t *module, FILE *file)
{
    uint16_t lines;

    /* Calculate the structure length */
    LOAD_IMMEDIATE (module->i_config_items);
    LOAD_IMMEDIATE (module->i_bool_items);
    LOAD_IMMEDIATE (lines);

    /* Allocate memory */
    if (lines)
    {
        module->p_config = malloc (lines * sizeof (module_config_t));
        if (unlikely(module->p_config == NULL))
        {
            module->confsize = 0;
            return -1;
        }
    }
    else
        module->p_config = NULL;
    module->confsize = lines;

    /* Do the duplication job */
    for (size_t i = 0; i < lines; i++)
        if (CacheLoadConfig (module->p_config + i, file))
            return -1;
    return 0;
error:
    return -1; /* FIXME: leaks */
}


/**
 * Loads a plugins cache file.
 *
 * This function will load the plugin cache if present and valid. This cache
 * will in turn be queried by AllocateAllPlugins() to see if it needs to
 * actually load the dynamically loadable module.
 * This allows us to only fully load plugins when they are actually used.
 */
size_t CacheLoad( vlc_object_t *p_this, const char *dir, module_cache_t **r )
{
    char *psz_filename;
    FILE *file;
    int i_size, i_read;
    char p_cachestring[sizeof(CACHE_STRING)];
    size_t i_cache;
    int32_t i_marker;

    assert( dir != NULL );

    *r = NULL;
    if( asprintf( &psz_filename, "%s"DIR_SEP CACHE_NAME, dir ) == -1 )
        return 0;

    msg_Dbg( p_this, "loading plugins cache file %s", psz_filename );

    file = vlc_fopen( psz_filename, "rb" );
    if( !file )
    {
        msg_Warn( p_this, "cannot read %s (%m)",
                  psz_filename );
        free( psz_filename );
        return 0;
    }
    free( psz_filename );

    /* Check the file is a plugins cache */
    i_size = sizeof(CACHE_STRING) - 1;
    i_read = fread( p_cachestring, 1, i_size, file );
    if( i_read != i_size ||
        memcmp( p_cachestring, CACHE_STRING, i_size ) )
    {
        msg_Warn( p_this, "This doesn't look like a valid plugins cache" );
        fclose( file );
        return 0;
    }

#ifdef DISTRO_VERSION
    /* Check for distribution specific version */
    char p_distrostring[sizeof( DISTRO_VERSION )];
    i_size = sizeof( DISTRO_VERSION ) - 1;
    i_read = fread( p_distrostring, 1, i_size, file );
    if( i_read != i_size ||
        memcmp( p_distrostring, DISTRO_VERSION, i_size ) )
    {
        msg_Warn( p_this, "This doesn't look like a valid plugins cache" );
        fclose( file );
        return 0;
    }
#endif

    /* Check Sub-version number */
    i_read = fread( &i_marker, 1, sizeof(i_marker), file );
    if( i_read != sizeof(i_marker) || i_marker != CACHE_SUBVERSION_NUM )
    {
        msg_Warn( p_this, "This doesn't look like a valid plugins cache "
                  "(corrupted header)" );
        fclose( file );
        return 0;
    }

    /* Check header marker */
    i_read = fread( &i_marker, 1, sizeof(i_marker), file );
    if( i_read != sizeof(i_marker) ||
        i_marker != ftell( file ) - (int)sizeof(i_marker) )
    {
        msg_Warn( p_this, "This doesn't look like a valid plugins cache "
                  "(corrupted header)" );
        fclose( file );
        return 0;
    }

    if (fread( &i_cache, 1, sizeof(i_cache), file ) != sizeof(i_cache) )
    {
        msg_Warn( p_this, "This doesn't look like a valid plugins cache "
                  "(file too short)" );
        fclose( file );
        return 0;
    }

    module_cache_t *cache = NULL;

    for (size_t count = 0; count < i_cache;)
    {
        module_t *module;
        int i_submodules;

        module = vlc_module_create (NULL);

        /* Load additional infos */
        LOAD_STRING(module->psz_shortname);
        LOAD_STRING(module->psz_longname);
        LOAD_STRING(module->psz_help);

        LOAD_IMMEDIATE(module->i_shortcuts);
        if (module->i_shortcuts > MODULE_SHORTCUT_MAX)
            goto error;
        else
        {
            module->pp_shortcuts =
                              xmalloc (sizeof (*module->pp_shortcuts) * module->i_shortcuts);
            for (unsigned j = 0; j < module->i_shortcuts; j++)
                LOAD_STRING(module->pp_shortcuts[j]);
        }

        LOAD_STRING(module->psz_capability);
        LOAD_IMMEDIATE(module->i_score);
        LOAD_IMMEDIATE(module->b_unloadable);

        /* Config stuff */
        if (CacheLoadModuleConfig (module, file) != VLC_SUCCESS)
            goto error;

        LOAD_STRING(module->domain);
        if (module->domain != NULL)
            vlc_bindtextdomain (module->domain);

        LOAD_IMMEDIATE( i_submodules );

        while( i_submodules-- )
        {
            module_t *submodule = vlc_module_create (module);
            free (submodule->pp_shortcuts);
            LOAD_STRING(submodule->psz_shortname);
            LOAD_STRING(submodule->psz_longname);

            LOAD_IMMEDIATE(submodule->i_shortcuts);
            if (submodule->i_shortcuts > MODULE_SHORTCUT_MAX)
                goto error;
            else
            {
                submodule->pp_shortcuts =
                           xmalloc (sizeof (*submodule->pp_shortcuts) * submodule->i_shortcuts);
                for (unsigned j = 0; j < submodule->i_shortcuts; j++)
                    LOAD_STRING(submodule->pp_shortcuts[j]);
            }

            LOAD_STRING(submodule->psz_capability);
            LOAD_IMMEDIATE(submodule->i_score);
        }

        char *path;
        struct stat st;

        /* Load common info */
        LOAD_STRING(path);
        if (path == NULL)
            goto error;
        LOAD_IMMEDIATE(st.st_mtime);
        LOAD_IMMEDIATE(st.st_size);

        CacheAdd (&cache, &count, path, &st, module);
        free (path);
        /* TODO: deal with errors */
    }
    fclose( file );

    *r = cache;
    return i_cache;

error:
    msg_Warn( p_this, "plugins cache not loaded (corrupted)" );

    /* TODO: cleanup */
    fclose( file );
    return 0;
}

#define SAVE_IMMEDIATE( a ) \
    if (fwrite (&(a), sizeof(a), 1, file) != 1) \
        goto error
#define SAVE_FLAG(a) \
    do { \
        char b = (a); \
        SAVE_IMMEDIATE(b); \
    } while (0)

static int CacheSaveString (FILE *file, const char *str)
{
    uint16_t size = (str != NULL) ? strlen (str) : 0;

    SAVE_IMMEDIATE (size);
    if (size != 0 && fwrite (str, 1, size, file) != size)
    {
error:
        return -1;
    }
    return 0;
}

#define SAVE_STRING( a ) \
    if (CacheSaveString (file, (a))) \
        goto error

static int CacheSaveConfig (FILE *file, const module_config_t *cfg)
{
    SAVE_IMMEDIATE (cfg->i_type);
    SAVE_IMMEDIATE (cfg->i_short);
    SAVE_FLAG (cfg->b_advanced);
    SAVE_FLAG (cfg->b_internal);
    SAVE_FLAG (cfg->b_unsaveable);
    SAVE_FLAG (cfg->b_safe);
    SAVE_FLAG (cfg->b_removed);
    SAVE_STRING (cfg->psz_type);
    SAVE_STRING (cfg->psz_name);
    SAVE_STRING (cfg->psz_text);
    SAVE_STRING (cfg->psz_longtext);
    SAVE_IMMEDIATE (cfg->list_count);

    if (IsConfigStringType (cfg->i_type))
    {
        SAVE_STRING (cfg->orig.psz);
        if (cfg->list_count == 0)
            SAVE_IMMEDIATE (cfg->list.psz_cb); /* XXX: see CacheLoadConfig() */
        for (unsigned i = 0; i < cfg->list_count; i++)
            SAVE_STRING (cfg->list.psz[i]);
    }
    else
    {
        SAVE_IMMEDIATE (cfg->orig);
        SAVE_IMMEDIATE (cfg->min);
        SAVE_IMMEDIATE (cfg->max);
        if (cfg->list_count == 0)
            SAVE_IMMEDIATE (cfg->list.i_cb); /* XXX: see CacheLoadConfig() */
        for (unsigned i = 0; i < cfg->list_count; i++)
             SAVE_IMMEDIATE (cfg->list.i[i]);
    }
    for (unsigned i = 0; i < cfg->list_count; i++)
        SAVE_STRING (cfg->list_text[i]);

    return 0;
error:
    return -1;
}

static int CacheSaveModuleConfig (FILE *file, const module_t *module)
{
    uint16_t lines = module->confsize;

    SAVE_IMMEDIATE (module->i_config_items);
    SAVE_IMMEDIATE (module->i_bool_items);
    SAVE_IMMEDIATE (lines);

    for (size_t i = 0; i < lines; i++)
        if (CacheSaveConfig (file, module->p_config + i))
           goto error;

    return 0;
error:
    return -1;
}

static int CacheSaveBank( FILE *file, const module_cache_t *, size_t );

/**
 * Saves a module cache to disk, and release cache data from memory.
 */
void CacheSave (vlc_object_t *p_this, const char *dir,
               module_cache_t *entries, size_t n)
{
    char *filename = NULL, *tmpname = NULL;

    if (asprintf (&filename, "%s"DIR_SEP CACHE_NAME, dir ) == -1)
        goto out;

    if (asprintf (&tmpname, "%s.%"PRIu32, filename, (uint32_t)getpid ()) == -1)
        goto out;
    msg_Dbg (p_this, "saving plugins cache %s", filename);

    FILE *file = vlc_fopen (tmpname, "wb");
    if (file == NULL)
    {
        if (errno != EACCES && errno != ENOENT)
            msg_Warn (p_this, "cannot create %s (%m)", tmpname);
        goto out;
    }

    if (CacheSaveBank (file, entries, n))
    {
        msg_Warn (p_this, "cannot write %s (%m)", tmpname);
        clearerr (file);
        fclose (file);
        vlc_unlink (tmpname);
        goto out;
    }

#if !defined( _WIN32 ) && !defined( __OS2__ )
    vlc_rename (tmpname, filename); /* atomically replace old cache */
    fclose (file);
#else
    vlc_unlink (filename);
    fclose (file);
    vlc_rename (tmpname, filename);
#endif
out:
    free (filename);
    free (tmpname);

    for (size_t i = 0; i < n; i++)
        free (entries[i].path);
    free (entries);
}

static int CacheSaveSubmodule (FILE *, const module_t *);

static int CacheSaveBank (FILE *file, const module_cache_t *cache,
                          size_t i_cache)
{
    uint32_t i_file_size = 0;

    /* Contains version number */
    if (fputs (CACHE_STRING, file) == EOF)
        goto error;
#ifdef DISTRO_VERSION
    /* Allow binary maintaner to pass a string to detect new binary version*/
    if (fputs( DISTRO_VERSION, file ) == EOF)
        goto error;
#endif
    /* Sub-version number (to avoid breakage in the dev version when cache
     * structure changes) */
    i_file_size = CACHE_SUBVERSION_NUM;
    if (fwrite (&i_file_size, sizeof (i_file_size), 1, file) != 1 )
        goto error;

    /* Header marker */
    i_file_size = ftell( file );
    if (fwrite (&i_file_size, sizeof (i_file_size), 1, file) != 1)
        goto error;

    if (fwrite( &i_cache, sizeof (i_cache), 1, file) != 1)
        goto error;

    for (unsigned i = 0; i < i_cache; i++)
    {
        module_t *module = cache[i].p_module;
        uint32_t i_submodule;

        /* Save additional infos */
        SAVE_STRING(module->psz_shortname);
        SAVE_STRING(module->psz_longname);
        SAVE_STRING(module->psz_help);
        SAVE_IMMEDIATE(module->i_shortcuts);
        for (unsigned j = 0; j < module->i_shortcuts; j++)
            SAVE_STRING(module->pp_shortcuts[j]);

        SAVE_STRING(module->psz_capability);
        SAVE_IMMEDIATE(module->i_score);
        SAVE_IMMEDIATE(module->b_unloadable);

        /* Config stuff */
        if (CacheSaveModuleConfig (file, module))
            goto error;

        SAVE_STRING(module->domain);

        i_submodule = module->submodule_count;
        SAVE_IMMEDIATE( i_submodule );
        if (CacheSaveSubmodule (file, module->submodule))
            goto error;

        /* Save common info */
        SAVE_STRING(cache[i].path);
        SAVE_IMMEDIATE(cache[i].mtime);
        SAVE_IMMEDIATE(cache[i].size);
    }

    if (fflush (file)) /* flush libc buffers */
        goto error;
    return 0; /* success! */

error:
    return -1;
}

static int CacheSaveSubmodule( FILE *file, const module_t *p_module )
{
    if( !p_module )
        return 0;
    if( CacheSaveSubmodule( file, p_module->next ) )
        goto error;

    SAVE_STRING( p_module->psz_shortname );
    SAVE_STRING( p_module->psz_longname );
    SAVE_IMMEDIATE( p_module->i_shortcuts );
    for( unsigned j = 0; j < p_module->i_shortcuts; j++ )
         SAVE_STRING( p_module->pp_shortcuts[j] );

    SAVE_STRING( p_module->psz_capability );
    SAVE_IMMEDIATE( p_module->i_score );
    return 0;

error:
    return -1;
}

/*****************************************************************************
 * CacheMerge: Merge a cache module descriptor with a full module descriptor.
 *****************************************************************************/
void CacheMerge( vlc_object_t *p_this, module_t *p_cache, module_t *p_module )
{
    (void)p_this;

    p_cache->pf_activate = p_module->pf_activate;
    p_cache->pf_deactivate = p_module->pf_deactivate;
    p_cache->handle = p_module->handle;

    /* FIXME: This looks too simplistic an algorithm to me. What if the module
     * file was altered such that the number of order of submodules was
     * altered... after VLC started -- Courmisch, 09/2008 */
    module_t *p_child = p_module->submodule,
             *p_cchild = p_cache->submodule;
    while( p_child && p_cchild )
    {
        p_cchild->pf_activate = p_child->pf_activate;
        p_cchild->pf_deactivate = p_child->pf_deactivate;
        p_child = p_child->next;
        p_cchild = p_cchild->next;
    }

    p_cache->b_loaded = true;
    p_module->b_loaded = false;
}

/**
 * Looks up a plugin file in a table of cached plugins.
 */
module_t *CacheFind (module_cache_t *cache, size_t count,
                     const char *path, const struct stat *st)
{
    while (count > 0)
    {
        if (cache->path != NULL
         && !strcmp (cache->path, path)
         && cache->mtime == st->st_mtime
         && cache->size == st->st_size)
       {
            module_t *module = cache->p_module;
            cache->p_module = NULL;
            return module;
       }
       cache++;
       count--;
    }

    return NULL;
}

/** Adds entry to the cache */
int CacheAdd (module_cache_t **cachep, size_t *countp,
              const char *path, const struct stat *st, module_t *module)
{
    module_cache_t *cache = *cachep;
    const size_t count = *countp;

    cache = realloc (cache, (count + 1) * sizeof (*cache));
    if (unlikely(cache == NULL))
        return -1;
    *cachep = cache;

    cache += count;
    /* NOTE: strdup() could be avoided, but it would be a bit ugly */
    cache->path = strdup (path);
    cache->mtime = st->st_mtime;
    cache->size = st->st_size;
    cache->p_module = module;
    *countp = count + 1;
    return 0;
}

#endif /* HAVE_DYNAMIC_PLUGINS */
