path: root/options/m_config.c

/*
 * This file is part of mpv.
 *
 * mpv 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.
 *
 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

/// \file
/// \ingroup Config

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <strings.h>
#include <assert.h>
#include <stdbool.h>
#include <pthread.h>

#include "libmpv/client.h"

#include "mpv_talloc.h"

#include "m_config.h"
#include "options/m_option.h"
#include "common/common.h"
#include "common/global.h"
#include "common/msg.h"
#include "common/msg_control.h"
#include "misc/dispatch.h"
#include "misc/node.h"
#include "osdep/atomic.h"

extern const char mp_help_text[];

static const union m_option_value default_value;

// Profiles allow to predefine some sets of options that can then
// be applied later on with the internal -profile option.
#define MAX_PROFILE_DEPTH 20
// Maximal include depth.
#define MAX_RECURSION_DEPTH 8

// For use with m_config_cache.
struct m_config_shadow {
    struct m_config *root;
    pthread_mutex_t lock;
    // -- protected by lock
    struct m_config_data *data; // protected shadow copy of the option data
    struct m_config_cache **listeners;
    int num_listeners;
};

// Represents a sub-struct (OPT_SUBSTRUCT()).
struct m_config_group {
    const struct m_sub_options *group;
    int group_count;    // 1 + number of all sub groups owned by this (so
                        // m_config.groups[idx..idx+group_count] is used by the
                        // entire tree of sub groups included by this group)
    int parent_group;   // index of parent group into m_config.groups[], or
                        // -1 for group 0
    int parent_ptr;     // ptr offset in the parent group's data, or -1 if
                        // none
    int co_index;       // index of the first group opt into m_config.opts[]
    int co_end_index;   // index of the last group opt + 1 (i.e. exclusive)
};

// A copy of option data. Used for the main option struct, the shadow data,
// and copies for m_config_cache.
struct m_config_data {
    struct m_config *root;          // root config (with up-to-date data)
    int group_index;                // start index into m_config.groups[]
    struct m_group_data *gdata;     // user struct allocation (our copy of data)
    int num_gdata;                  // (group_index+num_gdata = end index)
    atomic_llong ts;                // last change timestamp we've seen
};

// Per m_config_data state for each m_config_group.
struct m_group_data {
    char *udata;        // pointer to group user option struct
    long long ts;       // incremented on every write access
};

struct m_profile {
    struct m_profile *next;
    char *name;
    char *desc;
    int num_opts;
    // Option/value pair array.
    char **opts;
};

// In the file local case, this contains the old global value.
struct m_opt_backup {
    struct m_opt_backup *next;
    struct m_config_option *co;
    void *backup;
};

static void add_sub_group(struct m_config *config, const char *name_prefix,
                          int parent_group_index, int parent_ptr,
                          const struct m_sub_options *subopts);

static struct m_group_data *m_config_gdata(struct m_config_data *data,
                                           int group_index)
{
    if (group_index < data->group_index ||
        group_index >= data->group_index + data->num_gdata)
        return NULL;

    return &data->gdata[group_index - data->group_index];
}

static int show_profile(struct m_config *config, bstr param)
{
    struct m_profile *p;
    if (!param.len)
        return M_OPT_MISSING_PARAM;
    if (!(p = m_config_get_profile(config, param))) {
        MP_ERR(config, "Unknown profile '%.*s'.\n", BSTR_P(param));
        return M_OPT_EXIT;
    }
    if (!config->profile_depth)
        MP_INFO(config, "Profile %s: %s\n", p->name,
                p->desc ? p->desc : "");
    config->profile_depth++;
    for (int i = 0; i < p->num_opts; i++) {
        MP_INFO(config, "%*s%s=%s\n", config->profile_depth, "",
                p->opts[2 * i], p->opts[2 * i + 1]);

        if (config->profile_depth < MAX_PROFILE_DEPTH
            && !strcmp(p->opts[2*i], "profile")) {
            char *e, *list = p->opts[2 * i + 1];
            while ((e = strchr(list, ','))) {
                int l = e - list;
                if (!l)
                    continue;
                show_profile(config, (bstr){list, e - list});
                list = e + 1;
            }
            if (list[0] != '\0')
                show_profile(config, bstr0(list));
        }
    }
    config->profile_depth--;
    if (!config->profile_depth)
        MP_INFO(config, "\n");
    return M_OPT_EXIT;
}

// The memcpys are supposed to work around the strict aliasing violation,
// that would result if we just dereferenced a void** (where the void** is
// actually casted from struct some_type* ). The dummy struct type is in
// theory needed, because void* and struct pointers could have different
// representations, while pointers to different struct types don't.
static void *substruct_read_ptr(const void *ptr)
{
    struct mp_dummy_ *res;
    memcpy(&res, ptr, sizeof(res));
    return res;
}
static void substruct_write_ptr(void *ptr, void *val)
{
    struct mp_dummy_ *src = val;
    memcpy(ptr, &src, sizeof(src));
}

// Initialize a field with a given value. In case this is dynamic data, it has
// to be allocated and copied. src can alias dst.
static void init_opt_inplace(const struct m_option *opt, void *dst,
                             const void *src)
{
    // The option will use dynamic memory allocation iff it has a free callback.
    if (opt->type->free) {
        union m_option_value temp;
        memcpy(&temp, src, opt->type->size);
        memset(dst, 0, opt->type->size);
        m_option_copy(opt, dst, &temp);
    } else if (src != dst) {
        memcpy(dst, src, opt->type->size);
    }
}

static void alloc_group(struct m_config_data *data, int group_index,
                        struct m_config_data *copy)
{
    assert(group_index == data->group_index + data->num_gdata);
    assert(group_index < data->root->num_groups);
    struct m_config_group *group = &data->root->groups[group_index];
    const struct m_sub_options *opts = group->group;

    MP_TARRAY_GROW(data, data->gdata, data->num_gdata);
    struct m_group_data *gdata = &data->gdata[data->num_gdata++];

    struct m_group_data *copy_gdata =
        copy ? m_config_gdata(copy, group_index) : NULL;

    *gdata = (struct m_group_data){
        .udata = talloc_zero_size(data, opts->size),
        .ts = copy_gdata ? copy_gdata->ts : 0,
    };

    if (opts->defaults)
        memcpy(gdata->udata, opts->defaults, opts->size);

    char *copy_src = copy_gdata ? copy_gdata->udata : NULL;

    for (int n = group->co_index; n < group->co_end_index; n++) {
        assert(n >= 0 && n < data->root->num_opts);
        struct m_config_option *co = &data->root->opts[n];

        if (co->opt->offset < 0 || co->opt->type->size == 0)
            continue;

        void *dst = gdata->udata + co->opt->offset;
        const void *defptr = co->opt->defval ? co->opt->defval : dst;
        if (copy_src)
            defptr = copy_src + co->opt->offset;

        init_opt_inplace(co->opt, dst, defptr);
    }

    // If there's a parent, update its pointer to the new struct.
    if (group->parent_