mirror/RetroArch
1
0
Fork 0
mirror of https://github.com/libretro/RetroArch synced 2025-03-14 10:21:46 +00:00
Code Issues Packages Projects Releases Wiki Activity

create a single fetchfs backend instead of 1 per file

Browse Source 
symlinking manifest entries and using a baseurl gives us a way to
create just a single fetchfs backend (and a single thread) since
emscripten upstream is not willing to integrate manifest support to
fetchfs directly.

Retroarch embedders could use this to get assets or other resources
lazily or chunk-by-chunk for large files.
This commit is contained in:
Joseph C. Osborn 2025-03-10 14:55:54 -07:00
parent 9e64cce10f
commit 809e5d78be
1 changed files with 59 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
frontend/drivers/platform_emscripten.c
View File

@ -491,6 +491,7 @@ void platform_emscripten_mount_filesystems(void)
{
char *opfs_mount = getenv("OPFS_MOUNT");
char *fetch_manifest = getenv("FETCH_MANIFEST");
char *fetch_base_dir = getenv("FETCH_BASE_DIR");
if (opfs_mount)
{
int res;
@ -518,20 +519,23 @@ void platform_emscripten_mount_filesystems(void)
abort();
}
}
if (fetch_manifest)
if (fetch_manifest || fetch_base_dir)
{
/* fetch_manifest should be a path to a manifest file.
manifest files have this format:
BASEURL
URL PATH
URL PATH
URL PATH
...
Where URL may not contain spaces, but PATH may.
URL segments are relative to BASEURL.
*/
int max_line_len = 1024;
if (!(fetch_manifest && fetch_base_dir))
printf("[FetchFS] must specify both FETCH_MANIFEST and FETCH_BASE_DIR\n");
printf("[FetchFS] read fetch manifest from %s\n", fetch_manifest);
FILE *file = fopen(fetch_manifest, "r");
if (!file)
@ -541,44 +545,66 @@ void platform_emscripten_mount_filesystems(void)
}
char *line = calloc(sizeof(char), max_line_len);
size_t len = max_line_len;
while (getline(&line, &len, file) != -1)
if (getline(&line, &len, file) == -1 || len == 0)
printf("[FetchFS] missing base URL, skipping fetch initialization\n");
else
{
char *path = strstr(line, " ");
char *base_url = strdup(line);
backend_t fetch;
int fd;
if (len <= 2 || !path)
// Don't create fetch backend unless manifest actually has entries
while (getline(&line, &len, file) != -1)
{
printf("[FetchFS] Manifest file has invalid line %s\n", line);
continue;
}
*path = '\0';
path += 1;
path[strcspn(path, "\r\n")] = '\0';
printf("[FetchFS] Fetch %s from %s\n", path, line);
{
char *parent = strdup(path);
path_parent_dir(parent, strlen(parent));
if (!path_mkdir(parent))
if (!fetch)
{
printf("[FetchFS] mkdir error %d\n", errno);
fetch = wasmfs_create_fetch_backend(base_url, 16*1024*1024);
wasmfs_create_directory(fetch_base_dir, 0777, fetch);
}
char *realfs_path = strstr(line, " "), *url = line;
int fd;
if(len <= 2 || !realfs_path)
{
printf("[FetchFS] Manifest file has invalid line %s\n",line);
continue;
}
*realfs_path = '\0';
realfs_path += 1;
realfs_path[strcspn(realfs_path, "\r\n")] = '\0';
printf("[FetchFS] Fetch %s from URL %s / %s, fetched path %s / %s\n", realfs_path, base_url, url, fetch_base_dir, url);
char fetchfs_path[PATH_MAX];
fill_pathname_join(fetchfs_path, fetch_base_dir, url, sizeof(fetchfs_path));
/* Make the directories for link path */
{
char *parent = strdup(realfs_path);
path_parent_dir(parent, strlen(parent));
if(!path_mkdir(parent)) {
printf("[FetchFS] mkdir error %s %d\n", realfs_path, errno);
abort();
}
free(parent);
}
/* Make the directories for URL path */
{
char *parent = strdup(fetchfs_path);
path_parent_dir(parent, strlen(parent));
if(!path_mkdir(parent)) {
printf("[FetchFS] mkdir error %s %d\n", fetchfs_path, errno);
abort();
}
free(parent);
}
fd = open(fetchfs_path, O_CREAT);
if(!fd) {
printf("[FetchFS] couldn't create fetch file %s\n", fetchfs_path);
abort();
}
free(parent);
close(fd);
if(symlink(fetchfs_path, realfs_path) != 0) {
printf("[FetchFS] couldn't create link %s to fetch file %s (errno %d)\n", realfs_path, fetchfs_path, errno);
abort();
}
len = max_line_len;
}
fetch = wasmfs_create_fetch_backend(line, 16*1024*1024);
if (!fetch)
{
printf("[FetchFS] couldn't create fetch backend\n");
abort();
}
fd = wasmfs_create_file(path, 0777, fetch);
if (!fd)
{
printf("[FetchFS] couldn't create fetch file\n");
abort();
}
close(fd);
len = max_line_len;
free(base_url);
}
fclose(file);
free(line);