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janet/src/core/filewatch.c
2024-08-18 15:44:59 -05:00

624 lines
22 KiB
C

/*
* Copyright (c) 2024 Calvin Rose
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifndef JANET_AMALG
#include "features.h"
#include <janet.h>
#include "util.h"
#endif
#ifdef JANET_EV
#ifdef JANET_FILEWATCH
#ifdef JANET_LINUX
#include <sys/inotify.h>
#include <unistd.h>
#endif
#ifdef JANET_WINDOWS
#include <windows.h>
#endif
typedef struct {
const char *name;
uint32_t flag;
} JanetWatchFlagName;
typedef struct {
#ifndef JANET_WINDOWS
JanetStream *stream;
#endif
JanetTable* watch_descriptors;
JanetChannel *channel;
uint32_t default_flags;
int is_watching;
} JanetWatcher;
#ifdef JANET_LINUX
#include <sys/inotify.h>
#include <unistd.h>
static const JanetWatchFlagName watcher_flags_linux[] = {
{"access", IN_ACCESS},
{"all", IN_ALL_EVENTS},
{"attrib", IN_ATTRIB},
{"close-nowrite", IN_CLOSE_NOWRITE},
{"close-write", IN_CLOSE_WRITE},
{"create", IN_CREATE},
{"delete", IN_DELETE},
{"delete-self", IN_DELETE_SELF},
{"ignored", IN_IGNORED},
{"modify", IN_MODIFY},
{"move-self", IN_MOVE_SELF},
{"moved-from", IN_MOVED_FROM},
{"moved-to", IN_MOVED_TO},
{"open", IN_OPEN},
{"q-overflow", IN_Q_OVERFLOW},
{"unmount", IN_UNMOUNT},
};
static uint32_t decode_watch_flags(const Janet *options, int32_t n) {
uint32_t flags = 0;
for (int32_t i = 0; i < n; i++) {
if (!(janet_checktype(options[i], JANET_KEYWORD))) {
janet_panicf("expected keyword, got %v", options[i]);
}
JanetKeyword keyw = janet_unwrap_keyword(options[i]);
const JanetWatchFlagName *result = janet_strbinsearch(watcher_flags_linux,
sizeof(watcher_flags_linux) / sizeof(JanetWatchFlagName),
sizeof(JanetWatchFlagName),
keyw);
if (!result) {
janet_panicf("unknown inotify flag %v", options[i]);
}
flags |= result->flag;
}
return flags;
}
static void janet_watcher_init(JanetWatcher *watcher, JanetChannel *channel, uint32_t default_flags) {
int fd;
do {
fd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
} while (fd == -1 && errno == EINTR);
if (fd == -1) {
janet_panicv(janet_ev_lasterr());
}
watcher->watch_descriptors = janet_table(0);
watcher->channel = channel;
watcher->default_flags = default_flags;
watcher->is_watching = 0;
watcher->stream = janet_stream(fd, JANET_STREAM_READABLE, NULL);
}
static void janet_watcher_add(JanetWatcher *watcher, const char *path, uint32_t flags) {
if (watcher->stream == NULL) janet_panic("watcher closed");
int result;
do {
result = inotify_add_watch(watcher->stream->handle, path, flags);
} while (result == -1 && errno == EINTR);
if (result == -1) {
janet_panicv(janet_ev_lasterr());
}
Janet name = janet_cstringv(path);
Janet wd = janet_wrap_integer(result);
janet_table_put(watcher->watch_descriptors, name, wd);
janet_table_put(watcher->watch_descriptors, wd, name);
}
static void janet_watcher_remove(JanetWatcher *watcher, const char *path) {
if (watcher->stream == NULL) janet_panic("watcher closed");
Janet check = janet_table_get(watcher->watch_descriptors, janet_cstringv(path));
janet_assert(janet_checktype(check, JANET_NUMBER), "bad watch descriptor");
int watch_handle = janet_unwrap_integer(check);
int result;
do {
result = inotify_rm_watch(watcher->stream->handle, watch_handle);
} while (result != -1 && errno == EINTR);
if (result == -1) {
janet_panicv(janet_ev_lasterr());
}
}
static void watcher_callback_read(JanetFiber *fiber, JanetAsyncEvent event) {
JanetStream *stream = fiber->ev_stream;
JanetWatcher *watcher = *((JanetWatcher **) fiber->ev_state);
char buf[1024];
switch (event) {
default:
break;
case JANET_ASYNC_EVENT_MARK:
janet_mark(janet_wrap_abstract(watcher));
break;
case JANET_ASYNC_EVENT_CLOSE:
janet_schedule(fiber, janet_wrap_nil());
janet_async_end(fiber);
break;
case JANET_ASYNC_EVENT_ERR:
{
janet_schedule(fiber, janet_wrap_nil());
janet_async_end(fiber);
break;
}
read_more:
case JANET_ASYNC_EVENT_HUP:
case JANET_ASYNC_EVENT_INIT:
case JANET_ASYNC_EVENT_READ:
{
Janet name = janet_wrap_nil();
/* Assumption - read will never return partial events *
* From documentation:
*
* The behavior when the buffer given to read(2) is too small to
* return information about the next event depends on the kernel
* version: before Linux 2.6.21, read(2) returns 0; since Linux
* 2.6.21, read(2) fails with the error EINVAL. Specifying a buffer
* of size
*
* sizeof(struct inotify_event) + NAME_MAX + 1
*
* will be sufficient to read at least one event. */
ssize_t nread;
do {
nread = read(stream->handle, buf, sizeof(buf));
} while (nread == -1 && errno == EINTR);
/* Check for errors - special case errors that can just be waited on to fix */
if (nread == -1) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
break;
}
janet_cancel(fiber, janet_ev_lasterr());
fiber->ev_state = NULL;
janet_async_end(fiber);
break;
}
if (nread < (ssize_t) sizeof(struct inotify_event)) break;
/* Iterate through all events read from the buffer */
char *cursor = buf;
while (cursor < buf + nread) {
struct inotify_event inevent;
memcpy(&inevent, cursor, sizeof(inevent));
cursor += sizeof(inevent);
/* Read path of inevent */
if (inevent.len) {
name = janet_cstringv(cursor);
cursor += inevent.len;
}
/* Got an event */
Janet path = janet_table_get(watcher->watch_descriptors, janet_wrap_integer(inevent.wd));
JanetKV *event = janet_struct_begin(6);
janet_struct_put(event, janet_ckeywordv("wd"), janet_wrap_integer(inevent.wd));
janet_struct_put(event, janet_ckeywordv("wd-path"), path);
janet_struct_put(event, janet_ckeywordv("mask"), janet_wrap_integer(inevent.mask));
janet_struct_put(event, janet_ckeywordv("path"), name);
janet_struct_put(event, janet_ckeywordv("cookie"), janet_wrap_integer(inevent.cookie));
Janet etype = janet_ckeywordv("type");
const JanetWatchFlagName *wfn_end = watcher_flags_linux + sizeof(watcher_flags_linux) / sizeof(watcher_flags_linux[0]);
for (const JanetWatchFlagName *wfn = watcher_flags_linux; wfn < wfn_end; wfn++) {
if ((inevent.mask & wfn->flag) == wfn->flag) janet_struct_put(event, etype, janet_ckeywordv(wfn->name));
}
Janet eventv = janet_wrap_struct(janet_struct_end(event));
janet_channel_give(watcher->channel, eventv);
}
/* Read some more if possible */
goto read_more;
}
break;
}
}
static void janet_watcher_listen(JanetWatcher *watcher) {
if (watcher->is_watching) janet_panic("already watching");
watcher->is_watching = 1;
JanetFunction *thunk = janet_thunk_delay(janet_wrap_nil());
JanetFiber *fiber = janet_fiber(thunk, 64, 0, NULL);
JanetWatcher **state = janet_malloc(sizeof(JanetWatcher *)); /* Gross */
*state = watcher;
janet_async_start_fiber(fiber, watcher->stream, JANET_ASYNC_LISTEN_READ, watcher_callback_read, state);
janet_gcroot(janet_wrap_abstract(watcher));
}
static void janet_watcher_unlisten(JanetWatcher *watcher) {
if (!watcher->is_watching) return;
watcher->is_watching = 0;
janet_stream_close(watcher->stream);
janet_gcunroot(janet_wrap_abstract(watcher));
}
#elif JANET_WINDOWS
#define WATCHFLAG_RECURSIVE 0x100000u
static const JanetWatchFlagName watcher_flags_windows[] = {
{"all",
FILE_NOTIFY_CHANGE_ATTRIBUTES |
FILE_NOTIFY_CHANGE_CREATION |
FILE_NOTIFY_CHANGE_DIR_NAME |
FILE_NOTIFY_CHANGE_FILE_NAME |
FILE_NOTIFY_CHANGE_LAST_ACCESS |
FILE_NOTIFY_CHANGE_LAST_WRITE |
FILE_NOTIFY_CHANGE_SECURITY |
FILE_NOTIFY_CHANGE_SIZE |
WATCHFLAG_RECURSIVE},
{"attributes", FILE_NOTIFY_CHANGE_ATTRIBUTES},
{"creation", FILE_NOTIFY_CHANGE_CREATION},
{"dir-name", FILE_NOTIFY_CHANGE_DIR_NAME},
{"file-name", FILE_NOTIFY_CHANGE_FILE_NAME},
{"last-access", FILE_NOTIFY_CHANGE_LAST_ACCESS},
{"last-write", FILE_NOTIFY_CHANGE_LAST_WRITE},
{"recursive", WATCHFLAG_RECURSIVE},
{"security", FILE_NOTIFY_CHANGE_SECURITY},
{"size", FILE_NOTIFY_CHANGE_SIZE},
};
static uint32_t decode_watch_flags(const Janet *options, int32_t n) {
uint32_t flags = 0;
for (int32_t i = 0; i < n; i++) {
if (!(janet_checktype(options[i], JANET_KEYWORD))) {
janet_panicf("expected keyword, got %v", options[i]);
}
JanetKeyword keyw = janet_unwrap_keyword(options[i]);
const JanetWatchFlagName *result = janet_strbinsearch(watcher_flags_windows,
sizeof(watcher_flags_windows) / sizeof(JanetWatchFlagName),
sizeof(JanetWatchFlagName),
keyw);
if (!result) {
janet_panicf("unknown windows filewatch flag %v", options[i]);
}
flags |= result->flag;
}
return flags;
}
static void janet_watcher_init(JanetWatcher *watcher, JanetChannel *channel, uint32_t default_flags) {
watcher->watch_descriptors = janet_table(0);
watcher->channel = channel;
watcher->default_flags = default_flags;
watcher->is_watching = 0;
}
/* Since the file info padding includes embedded file names, we want to include more space for data.
* We also need to handle manually calculating changes if path names are too long, but ideally just avoid
* that scenario as much as possible */
#define FILE_INFO_PADDING (4096 * 4)
typedef struct {
OVERLAPPED overlapped;
JanetStream *stream;
JanetWatcher *watcher;
JanetFiber *fiber;
JanetString dir_path;
uint32_t flags;
uint64_t buf[FILE_INFO_PADDING / sizeof(uint64_t)]; /* Ensure alignment */
} OverlappedWatch;
#define NotifyChange FILE_NOTIFY_INFORMATION
static void read_dir_changes(OverlappedWatch *ow) {
BOOL result = ReadDirectoryChangesW(ow->stream->handle,
(NotifyChange *) ow->buf,
FILE_INFO_PADDING,
(ow->flags & WATCHFLAG_RECURSIVE) ? TRUE : FALSE,
ow->flags & ~WATCHFLAG_RECURSIVE,
NULL,
(OVERLAPPED *) ow,
NULL);
if (!result) {
janet_panicv(janet_ev_lasterr());
}
}
static const char* watcher_actions_windows[] = {
"unknown",
"added",
"removed",
"modified",
"renamed-old",
"renamed-new",
};
static void watcher_callback_read(JanetFiber *fiber, JanetAsyncEvent event) {
OverlappedWatch *ow = (OverlappedWatch *) fiber->ev_state;
JanetWatcher *watcher = ow->watcher;
switch (event) {
default:
break;
case JANET_ASYNC_EVENT_INIT:
janet_async_in_flight(fiber);
break;
case JANET_ASYNC_EVENT_MARK:
janet_mark(janet_wrap_abstract(ow->stream));
janet_mark(janet_wrap_fiber(ow->fiber));
janet_mark(janet_wrap_abstract(watcher));
janet_mark(janet_wrap_string(ow->dir_path));
break;
case JANET_ASYNC_EVENT_CLOSE:
janet_table_remove(ow->watcher->watch_descriptors, janet_wrap_string(ow->dir_path));
break;
case JANET_ASYNC_EVENT_ERR:
case JANET_ASYNC_EVENT_FAILED:
janet_stream_close(ow->stream);
break;
case JANET_ASYNC_EVENT_COMPLETE:
{
if (!watcher->is_watching) {
janet_stream_close(ow->stream);
break;
}
NotifyChange *fni = (NotifyChange *) ow->buf;
while (1) {
/* Got an event */
/* Extract name */
Janet filename;
if (fni->FileNameLength) {
int32_t nbytes = (int32_t) WideCharToMultiByte(CP_UTF8, 0, fni->FileName, fni->FileNameLength / sizeof(wchar_t), NULL, 0, NULL, NULL);
janet_assert(nbytes, "bad utf8 path");
uint8_t *into = janet_string_begin(nbytes);
WideCharToMultiByte(CP_UTF8, 0, fni->FileName, fni->FileNameLength / sizeof(wchar_t), into, nbytes, NULL, NULL);
filename = janet_wrap_string(janet_string_end(into));
} else {
filename = janet_cstringv("");
}
JanetKV *event = janet_struct_begin(3);
janet_struct_put(event, janet_ckeywordv("type"), janet_ckeywordv(watcher_actions_windows[fni->Action]));
janet_struct_put(event, janet_ckeywordv("file-name"), filename);
janet_struct_put(event, janet_ckeywordv("dir"), janet_wrap_string(ow->dir_path));
Janet eventv = janet_wrap_struct(janet_struct_end(event));
janet_channel_give(watcher->channel, eventv);
/* Next event */
if (!fni->NextEntryOffset) break;
fni = (NotifyChange *) ((char *)fni + fni->NextEntryOffset);
}
/* Make another call to read directory changes */
read_dir_changes(ow);
janet_async_in_flight(fiber);
}
break;
}
}
static void start_listening_ow(OverlappedWatch *ow) {
read_dir_changes(ow);
JanetStream *stream = ow->stream;
JanetFunction *thunk = janet_thunk_delay(janet_wrap_nil());
JanetFiber *fiber = janet_fiber(thunk, 64, 0, NULL);
fiber->supervisor_channel = janet_root_fiber()->supervisor_channel;
ow->fiber = fiber;
janet_async_start_fiber(fiber, stream, JANET_ASYNC_LISTEN_READ, watcher_callback_read, ow);
}
static void janet_watcher_add(JanetWatcher *watcher, const char *path, uint32_t flags) {
HANDLE handle = CreateFileA(path,
FILE_LIST_DIRECTORY | GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
NULL,
OPEN_EXISTING,
FILE_FLAG_OVERLAPPED | FILE_FLAG_BACKUP_SEMANTICS,
NULL);
if (handle == INVALID_HANDLE_VALUE) {
janet_panicv(janet_ev_lasterr());
}
JanetStream *stream = janet_stream(handle, JANET_STREAM_READABLE, NULL);
OverlappedWatch *ow = janet_malloc(sizeof(OverlappedWatch));
memset(ow, 0, sizeof(OverlappedWatch));
ow->stream = stream;
ow->dir_path = janet_cstring(path);
ow->fiber = NULL;
Janet pathv = janet_wrap_string(ow->dir_path);
ow->flags = flags | watcher->default_flags;
ow->watcher = watcher;
ow->overlapped.hEvent = CreateEvent(NULL, FALSE, 0, NULL); /* Do we need this */
Janet streamv = janet_wrap_pointer(ow);
janet_table_put(watcher->watch_descriptors, pathv, streamv);
if (watcher->is_watching) {
start_listening_ow(ow);
}
}
static void janet_watcher_remove(JanetWatcher *watcher, const char *path) {
Janet pathv = janet_cstringv(path);
Janet streamv = janet_table_get(watcher->watch_descriptors, pathv);
if (janet_checktype(streamv, JANET_NIL)) {
janet_panicf("path %v is not being watched", pathv);
}
janet_table_remove(watcher->watch_descriptors, pathv);
OverlappedWatch *ow = janet_unwrap_pointer(streamv);
janet_stream_close(ow->stream);
}
static void janet_watcher_listen(JanetWatcher *watcher) {
if (watcher->is_watching) janet_panic("already watching");
watcher->is_watching = 1;
for (int32_t i = 0; i < watcher->watch_descriptors->capacity; i++) {
const JanetKV *kv = watcher->watch_descriptors->data + i;
if (!janet_checktype(kv->value, JANET_POINTER)) continue;
OverlappedWatch *ow = janet_unwrap_pointer(kv->value);
start_listening_ow(ow);
}
janet_gcroot(janet_wrap_abstract(watcher));
}
static void janet_watcher_unlisten(JanetWatcher *watcher) {
if (!watcher->is_watching) return;
watcher->is_watching = 0;
for (int32_t i = 0; i < watcher->watch_descriptors->capacity; i++) {
const JanetKV *kv = watcher->watch_descriptors->data + i;
if (!janet_checktype(kv->value, JANET_POINTER)) continue;
OverlappedWatch *ow = janet_unwrap_pointer(kv->value);
janet_stream_close(ow->stream);
}
janet_table_clear(watcher->watch_descriptors);
janet_gcunroot(janet_wrap_abstract(watcher));
}
#else
/* Default implementation */
static uint32_t decode_watch_flags(const Janet *options, int32_t n) {
(void) options;
(void) n;
return 0;
}
static void janet_watcher_init(JanetWatcher *watcher, JanetChannel *channel, uint32_t default_flags) {
(void) watcher;
(void) channel;
(void) default_flags;
janet_panic("filewatch not supported on this platform");
}
static void janet_watcher_add(JanetWatcher *watcher, const char *path, uint32_t flags) {
(void) watcher;
(void) flags;
(void) path;
janet_panic("nyi");
}
static void janet_watcher_remove(JanetWatcher *watcher, const char *path) {
(void) watcher;
(void) path;
janet_panic("nyi");
}
static void janet_watcher_listen(JanetWatcher *watcher) {
(void) watcher;
janet_panic("nyi");
}
static void janet_watcher_unlisten(JanetWatcher *watcher) {
(void) watcher;
janet_panic("nyi");
}
#endif
/* C Functions */
static int janet_filewatch_mark(void *p, size_t s) {
JanetWatcher *watcher = (JanetWatcher *) p;
(void) s;
if (watcher->channel == NULL) return 0; /* Incomplete initialization */
#ifdef JANET_WINDOWS
for (int32_t i = 0; i < watcher->watch_descriptors->capacity; i++) {
const JanetKV *kv = watcher->watch_descriptors->data + i;
if (!janet_checktype(kv->value, JANET_POINTER)) continue;
OverlappedWatch *ow = janet_unwrap_pointer(kv->value);
janet_mark(janet_wrap_fiber(ow->fiber));
janet_mark(janet_wrap_abstract(ow->stream));
janet_mark(janet_wrap_string(ow->dir_path));
}
#else
janet_mark(janet_wrap_abstract(watcher->stream));
#endif
janet_mark(janet_wrap_abstract(watcher->channel));
janet_mark(janet_wrap_table(watcher->watch_descriptors));
return 0;
}
static const JanetAbstractType janet_filewatch_at = {
"filewatch/watcher",
NULL,
janet_filewatch_mark,
JANET_ATEND_GCMARK
};
JANET_CORE_FN(cfun_filewatch_make,
"(filewatch/new channel &opt default-flags)",
"Create a new filewatcher that will give events to a channel channel.") {
janet_arity(argc, 1, -1);
JanetChannel *channel = janet_getchannel(argv, 0);
JanetWatcher *watcher = janet_abstract(&janet_filewatch_at, sizeof(JanetWatcher));
uint32_t default_flags = decode_watch_flags(argv + 1, argc - 1);
janet_watcher_init(watcher, channel, default_flags);
return janet_wrap_abstract(watcher);
}
JANET_CORE_FN(cfun_filewatch_add,
"(filewatch/add watcher path &opt flags)",
"Add a path to the watcher.") {
janet_arity(argc, 2, -1);
JanetWatcher *watcher = janet_getabstract(argv, 0, &janet_filewatch_at);
const char *path = janet_getcstring(argv, 1);
uint32_t flags = watcher->default_flags | decode_watch_flags(argv + 2, argc - 2);
janet_watcher_add(watcher, path, flags);
return argv[0];
}
JANET_CORE_FN(cfun_filewatch_remove,
"(filewatch/remove watcher path)",
"Remove a path from the watcher.") {
janet_fixarity(argc, 2);
JanetWatcher *watcher = janet_getabstract(argv, 0, &janet_filewatch_at);
const char *path = janet_getcstring(argv, 1);
janet_watcher_remove(watcher, path);
return argv[0];
}
JANET_CORE_FN(cfun_filewatch_listen,
"(filewatch/listen watcher)",
"Listen for changes in the watcher.") {
janet_fixarity(argc, 1);
JanetWatcher *watcher = janet_getabstract(argv, 0, &janet_filewatch_at);
janet_watcher_listen(watcher);
return janet_wrap_nil();
}
JANET_CORE_FN(cfun_filewatch_unlisten,
"(filewatch/unlisten watcher)",
"Stop listening for changes on a given watcher.") {
janet_fixarity(argc, 1);
JanetWatcher *watcher = janet_getabstract(argv, 0, &janet_filewatch_at);
janet_watcher_unlisten(watcher);
return janet_wrap_nil();
}
/* Module entry point */
void janet_lib_filewatch(JanetTable *env) {
JanetRegExt cfuns[] = {
JANET_CORE_REG("filewatch/new", cfun_filewatch_make),
JANET_CORE_REG("filewatch/add", cfun_filewatch_add),
JANET_CORE_REG("filewatch/remove", cfun_filewatch_remove),
JANET_CORE_REG("filewatch/listen", cfun_filewatch_listen),
JANET_CORE_REG("filewatch/unlisten", cfun_filewatch_unlisten),
JANET_REG_END
};
janet_core_cfuns_ext(env, NULL, cfuns);
}
#endif
#endif