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mirror of https://github.com/mpv-player/mpv synced 2024-10-30 04:46:41 +01:00
mpv/player/scripting.c
wm4 11c573fda0 scripting: change when/how player waits for scripts being loaded
Fundamentally, scripts are loaded asynchronously, but as a feature,
there was code to wait until a script is loaded (for a certain arbitrary
definition of "loaded"). This was done in scripting.c with the
wait_loaded() function.

This called mp_idle(), and since there are commands to load/unload
scripts, it meant the player core loop could be entered recursively. I
think this is a major complication and has some problems. For example,
if you had a script that does 'os.execute("sleep inf")', then every time
you ran a command to load an instance of the script would add a new
stack frame of mp_idle(). This would lead to some sort of reentrancy
horror that is hard to debug. Also misc/dispatch.c contains a somewhat
tricky mess to support such recursive invocations. There were also some
bugs due to this and due to unforeseen interactions with other messes.

This scripting stuff was the only thing making use of that reentrancy,
and future commands that have "logical" waiting for something should be
implemented differently. So get rid of it.

Change the code to wait only in the player initialization phase: the
only place where it really has to wait is before playback is started,
because scripts might want to set options or hooks that interact with
playback initialization. Unloading of builtin scripts (can happen with
e.g. "set osc no") is left asynchronous; the unloading wasn't too robust
anyway, and this change won't make a difference if someone is trying to
break it intentionally. Note that this is not in mp_initialize(),
because mpv_initialize() uses this by locking the core, which would have
the same problem.

In the future, commands which logically wait should use different
mechanisms. Originally I thought the current approach (that is removed
with this commit) should be used, but it's too much of a mess and can't
even be used in some cases. Examples are:
- "loadfile" should be made blocking (needs to run the normal player
  code and manually unblock the thread issuing the command)
- "add-sub" should not freeze the player until the URL is opened (needs
  to run opening on a separate thread)
Possibly the current scripting behavior could be restored once new
mechanisms exist, and if it turns out that anyone needs it.

With this commit there should be no further instances of recursive
playloop invocations (other than the case in the following commit),
since all mp_idle()/mp_wait_events() calls are done strictly from the
main thread (and not commands/properties or libmpv client API that
"lock" the main thread).
2018-04-18 01:17:41 +03:00

268 lines
7.6 KiB
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/>.
*/
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <dirent.h>
#include <math.h>
#include <pthread.h>
#include <assert.h>
#include "config.h"
#include "osdep/io.h"
#include "osdep/threads.h"
#include "common/common.h"
#include "common/msg.h"
#include "options/path.h"
#include "misc/bstr.h"
#include "core.h"
#include "client.h"
#include "libmpv/client.h"
extern const struct mp_scripting mp_scripting_lua;
extern const struct mp_scripting mp_scripting_cplugin;
extern const struct mp_scripting mp_scripting_js;
static const struct mp_scripting *const scripting_backends[] = {
#if HAVE_LUA
&mp_scripting_lua,
#endif
#if HAVE_CPLUGINS
&mp_scripting_cplugin,
#endif
#if HAVE_JAVASCRIPT
&mp_scripting_js,
#endif
NULL
};
static char *script_name_from_filename(void *talloc_ctx, const char *fname)
{
fname = mp_basename(fname);
if (fname[0] == '@')
fname += 1;
char *name = talloc_strdup(talloc_ctx, fname);
// Drop file extension
char *dot = strrchr(name, '.');
if (dot)
*dot = '\0';
// Turn it into a safe identifier - this is used with e.g. dispatching
// input via: "send scriptname ..."
for (int n = 0; name[n]; n++) {
char c = name[n];
if (!(c >= 'A' && c <= 'Z') && !(c >= 'a' && c <= 'z') &&
!(c >= '0' && c <= '9'))
name[n] = '_';
}
return talloc_asprintf(talloc_ctx, "%s", name);
}
struct thread_arg {
struct mp_log *log;
const struct mp_scripting *backend;
mpv_handle *client;
const char *fname;
};
static void *script_thread(void *p)
{
pthread_detach(pthread_self());
struct thread_arg *arg = p;
char name[90];
snprintf(name, sizeof(name), "%s (%s)", arg->backend->name,
mpv_client_name(arg->client));
mpthread_set_name(name);
if (arg->backend->load(arg->client, arg->fname) < 0)
MP_ERR(arg, "Could not load %s %s\n", arg->backend->name, arg->fname);
mpv_destroy(arg->client);
talloc_free(arg);
return NULL;
}
static int mp_load_script(struct MPContext *mpctx, const char *fname)
{
char *ext = mp_splitext(fname, NULL);
const struct mp_scripting *backend = NULL;
for (int n = 0; scripting_backends[n]; n++) {
const struct mp_scripting *b = scripting_backends[n];
if (ext && strcasecmp(ext, b->file_ext) == 0) {
backend = b;
break;
}
}
if (!backend) {
MP_VERBOSE(mpctx, "Can't load unknown script: %s\n", fname);
return -1;
}
struct thread_arg *arg = talloc_ptrtype(NULL, arg);
char *name = script_name_from_filename(arg, fname);
*arg = (struct thread_arg){
.fname = talloc_strdup(arg, fname),
.backend = backend,
// Create the client before creating the thread; otherwise a race
// condition could happen, where MPContext is destroyed while the
// thread tries to create the client.
.client = mp_new_client(mpctx->clients, name),
};
if (!arg->client) {
talloc_free(arg);
return -1;
}
mp_client_set_weak(arg->client);
arg->log = mp_client_get_log(arg->client);
MP_DBG(arg, "Loading %s %s...\n", backend->name, fname);
pthread_t thread;
if (pthread_create(&thread, NULL, script_thread, arg)) {
mpv_destroy(arg->client);
talloc_free(arg);
return -1;
}
return 0;
}
int mp_load_user_script(struct MPContext *mpctx, const char *fname)
{
char *path = mp_get_user_path(NULL, mpctx->global, fname);
int ret = mp_load_script(mpctx, path);
talloc_free(path);
return ret;
}
static int compare_filename(const void *pa, const void *pb)
{
char *a = (char *)pa;
char *b = (char *)pb;
return strcmp(a, b);
}
static char **list_script_files(void *talloc_ctx, char *path)
{
char **files = NULL;
int count = 0;
DIR *dp = opendir(path);
if (!dp)
return NULL;
struct dirent *ep;
while ((ep = readdir(dp))) {
char *fname = mp_path_join(talloc_ctx, path, ep->d_name);
struct stat s;
if (!stat(fname, &s) && S_ISREG(s.st_mode))
MP_TARRAY_APPEND(talloc_ctx, files, count, fname);
}
closedir(dp);
if (files)
qsort(files, count, sizeof(char *), compare_filename);
MP_TARRAY_APPEND(talloc_ctx, files, count, NULL);
return files;
}
static void load_builtin_script(struct MPContext *mpctx, bool enable,
const char *fname)
{
void *tmp = talloc_new(NULL);
// (The name doesn't have to match if there were conflicts with other
// scripts, so this is on best-effort basis.)
char *name = script_name_from_filename(tmp, fname);
if (enable != mp_client_exists(mpctx, name)) {
if (enable) {
mp_load_script(mpctx, fname);
} else {
// Try to unload it by sending a shutdown event. This can be
// unreliable, because user scripts could have clashing names, or
// disabling and then quickly re-enabling a builtin script might
// detect the still-terminating script as loaded.
mp_client_send_event(mpctx, name, 0, MPV_EVENT_SHUTDOWN, NULL);
}
}
talloc_free(tmp);
}
void mp_load_builtin_scripts(struct MPContext *mpctx)
{
load_builtin_script(mpctx, mpctx->opts->lua_load_osc, "@osc.lua");
load_builtin_script(mpctx, mpctx->opts->lua_load_ytdl, "@ytdl_hook.lua");
load_builtin_script(mpctx, mpctx->opts->lua_load_stats, "@stats.lua");
}
void mp_load_scripts(struct MPContext *mpctx)
{
// Load scripts from options
char **files = mpctx->opts->script_files;
for (int n = 0; files && files[n]; n++) {
if (files[n][0])
mp_load_user_script(mpctx, files[n]);
}
if (!mpctx->opts->auto_load_scripts)
return;
// Load all scripts
void *tmp = talloc_new(NULL);
char **scriptsdir = mp_find_all_config_files(tmp, mpctx->global, "scripts");
for (int i = 0; scriptsdir && scriptsdir[i]; i++) {
files = list_script_files(tmp, scriptsdir[i]);
for (int n = 0; files && files[n]; n++)
mp_load_script(mpctx, files[n]);
}
talloc_free(tmp);
}
#if HAVE_CPLUGINS
#include <dlfcn.h>
#define MPV_DLOPEN_FN "mpv_open_cplugin"
typedef int (*mpv_open_cplugin)(mpv_handle *handle);
static int load_cplugin(struct mpv_handle *client, const char *fname)
{
MPContext *ctx = mp_client_get_core(client);
void *lib = dlopen(fname, RTLD_NOW | RTLD_LOCAL);
if (!lib)
goto error;
// Note: once loaded, we never unload, as unloading the libraries linked to
// the plugin can cause random serious problems.
mpv_open_cplugin sym = (mpv_open_cplugin)dlsym(lib, MPV_DLOPEN_FN);
if (!sym)
goto error;
return sym(client) ? -1 : 0;
error: ;
char *err = dlerror();
if (err)
MP_ERR(ctx, "C plugin error: '%s'\n", err);
return -1;
}
const struct mp_scripting mp_scripting_cplugin = {
.name = "SO plugin",
.file_ext = "so",
.load = load_cplugin,
};
#endif