townengine/third-party/x-watcher/x-watcher.h

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2024-08-21 13:55:34 +00:00
#ifndef __X_WATCHER_H
#define __X_WATCHER_H
// necessary includes for the public stuff
#include <pthread.h>
#include <stdbool.h>
#if defined(__linux__)
// noop
#elif defined(__WIN32__)
#include <windows.h>
#include <stdint.h>
#else
#error "Unsupported"
#endif
// PUBLIC STUFF
typedef enum event {
XWATCHER_FILE_UNSPECIFIED,
XWATCHER_FILE_REMOVED,
XWATCHER_FILE_CREATED,
XWATCHER_FILE_MODIFIED,
XWATCHER_FILE_OPENED,
XWATCHER_FILE_ATTRIBUTES_CHANGED,
XWATCHER_FILE_NONE,
XWATCHER_FILE_RENAMED,
// probs more but i couldn't care much
} XWATCHER_FILE_EVENT;
typedef struct xWatcher_reference {
char *path;
void (*callback_func)(
XWATCHER_FILE_EVENT event,
const char *path,
int context,
void *additional_data);
int context;
void *additional_data;
} xWatcher_reference;
struct file {
// just the file name alone
char *name;
// used for adding (additional) context in the handler (if needed)
int context;
// in case you'd like to avoid global variables
void *additional_data;
void (*callback_func)(
XWATCHER_FILE_EVENT event,
const char *path,
int context,
void *additional_data);
} file;
struct directory {
// list of files
struct file *files;
char *path;
// used for adding (additional) context in the handler (if needed)
int context;
// in case you'd like to avoid global variables
void *additional_data;
void (*callback_func)(
XWATCHER_FILE_EVENT event,
const char *path,
int context,
void *additional_data);
#if defined(__linux__)
// we need additional file descriptors (per directory basis)
int inotify_watch_fd;
#elif defined(__WIN32__)
HANDLE handle;
OVERLAPPED overlapped;
uint8_t *event_buffer;
#else
#error "Unsupported"
#endif
} directory;
typedef struct x_watcher {
struct directory *directories;
pthread_t thread;
int thread_id;
bool alive;
#if defined(__linux__)
int inotify_fd; // fd == file descriptor (a common UNIX thing)
#elif defined(__WIN32__)
// literal noop
#else
#error "Unsupported"
#endif
} x_watcher;
// PRIVATE STUFF
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "array.h"
#ifdef __linux__
#include <sys/types.h>
#include <sys/inotify.h>
#include <errno.h>
#include <unistd.h>
#include <poll.h> // for POLLIN
#include <fcntl.h> // for O_NONBLOCK
#define EVENT_SIZE (sizeof(struct inotify_event))
#define BUF_LEN (1024 * (EVENT_SIZE + 16))
#define DIRBRK '/'
static inline void *__internal_xWatcherProcess(void *argument) {
x_watcher *watcher = (x_watcher*) argument;
char buffer[BUF_LEN];
ssize_t lenght;
struct directory *directories = watcher->directories;
while(watcher->alive) {
// poll for events
struct pollfd pfd = { watcher->inotify_fd, POLLIN, 0 };
int ret = poll(&pfd, 1, 50); // timeout of 50ms
if (ret < 0) {
// oops
fprintf(stderr, "poll failed: %s\n", strerror(errno));
break;
} else if (ret == 0) {
// Timeout with no events, move on.
continue;
}
// wait for the kernel to do it's thing
lenght = read(watcher->inotify_fd, buffer, BUF_LEN);
if(lenght < 0) {
// something messed up clearly
perror("read");
return NULL;
}
// pointer to the event structure
ssize_t i = 0;
while(i < lenght) {
// the event list itself
struct inotify_event *event = (struct inotify_event *)
&buffer[i];
// find directory for which this even matches via the descriptor
struct directory *directory = NULL;
for(size_t j = 0; j < arr_count(directories); j++) {
if(directories[j].inotify_watch_fd == event->wd) {
directory = &directories[j];
}
}
if(directory == NULL) {
fprintf(stderr,
"MATCHING FILE DESCRIPTOR NOT FOUND! ERROR!\n");
// BAIL????
}
// find matching file (if any)
struct file *file = NULL;
for(size_t j = 0; j < arr_count(directory->files); j++) {
if(strcmp(directory->files[j].name, event->name) == 0) {
file = &directory->files[j];
}
}
XWATCHER_FILE_EVENT send_event = XWATCHER_FILE_NONE;
if(event->mask & IN_CREATE)
send_event = XWATCHER_FILE_CREATED;
if(event->mask & IN_MODIFY)
send_event = XWATCHER_FILE_MODIFIED;
if(event->mask & IN_DELETE)
send_event = XWATCHER_FILE_REMOVED;
if(event->mask & IN_CLOSE_WRITE ||
event->mask & IN_CLOSE_NOWRITE)
send_event = XWATCHER_FILE_REMOVED;
if(event->mask & IN_ATTRIB)
send_event = XWATCHER_FILE_ATTRIBUTES_CHANGED;
if(event->mask & IN_OPEN)
send_event = XWATCHER_FILE_OPENED;
// file found(?)
if(file != NULL) {
if(send_event != XWATCHER_FILE_NONE) {
// figure out the file path size
size_t filepath_size = strlen(directory->path);
filepath_size += strlen(file->name);
filepath_size += 2;
// create file path string
char *filepath = (char*)malloc(filepath_size);
snprintf(filepath, filepath_size, "%s/%s",
directory->path, file->name);
// callback
file->callback_func(send_event,
filepath,
file->context,
file->additional_data);
// free that garbage
free(filepath);
}
} else {
// Cannot find file, lets try directory
if(directory->callback_func != NULL &&
send_event != XWATCHER_FILE_NONE) {
directory->callback_func(send_event,
directory->path,
directory->context,
directory->additional_data);
}
}
i += EVENT_SIZE + event->len;
}
}
// cleanup time
for(size_t i = 0; i < arr_count(watcher->directories); i++) {
struct directory *directory = &watcher->directories[i];
for(size_t j = 0; j < arr_count(directory->files); j++) {
struct file *file = &directory->files[j];
free(file->name);
}
arr_free(directory->files);
free(directory->path);
inotify_rm_watch(watcher->inotify_fd, directory->inotify_watch_fd);
}
close(watcher->inotify_fd);
arr_free(watcher->directories);
// should we signify that the thread is dead?
return NULL;
}
#elif defined(__WIN32__)
#include <tchar.h>
#define BUF_LEN 1024
#define DIRBRK '\\'
static inline void *__internal_xWatcherProcess(void *argument) {
x_watcher *watcher = (x_watcher*) argument;
struct directory *directories = watcher->directories;
// create an event list so we can still make use of the Windows API
HANDLE events[arr_count(directories)];
for(int i = 0; i < arr_count(directories); i++) {
events[i] = directories[i].overlapped.hEvent;
}
// obv first check if we need to stay alive
while(watcher->alive) {
// wait for any of the objects to respond
DWORD result = WaitForMultipleObjects(arr_count(directories),
events, FALSE, 50 /** timeout of 50ms **/);
// test which object was it
int object_index = -1;
for(int i = 0; i < arr_count(directories); i++) {
if(result == (WAIT_OBJECT_0 + i)) {
object_index = i;
break;
}
}
if(object_index == -1) {
if(result == WAIT_TIMEOUT) {
// it just timed out, let's continue
continue;
} else {
// RUNTIME ERROR! Let's bail
ExitProcess(GetLastError());
}
}
// shorhand for convenience
struct directory *dir = &directories[object_index];
// retrieve event data
DWORD bytes_transferred;
GetOverlappedResult(dir->handle,
&dir->overlapped,
&bytes_transferred, FALSE);
// assign the data's pointer to a proper format for convenience
FILE_NOTIFY_INFORMATION *event = (FILE_NOTIFY_INFORMATION*)
dir->event_buffer;
// loop through the data
for (;;) {
// figure out the wchar string size and allocate as needed
DWORD name_len = event->FileNameLength / sizeof(wchar_t);
char *name_char = malloc(sizeof(char)*(name_len+1));
size_t converted_chars;
// convert wchar* filename to char*
wcstombs_s(&converted_chars, name_char,
name_len+1, event->FileName, name_len);
// convert to proper event type
XWATCHER_FILE_EVENT send_event = XWATCHER_FILE_NONE;
switch (event->Action) {
case FILE_ACTION_ADDED:
send_event = XWATCHER_FILE_CREATED;
break;
case FILE_ACTION_REMOVED:
send_event = XWATCHER_FILE_REMOVED;
break;
case FILE_ACTION_MODIFIED:
send_event = XWATCHER_FILE_MODIFIED;
break;
case FILE_ACTION_RENAMED_OLD_NAME:
case FILE_ACTION_RENAMED_NEW_NAME:
send_event = XWATCHER_FILE_RENAMED;
break;
default:
send_event = XWATCHER_FILE_UNSPECIFIED;
break;
}
// find matching file (if any)
struct file *file = NULL;
for(size_t j = 0; j < arr_count(dir->files); j++) {
if(strcmp(dir->files[j].name, name_char) == 0) {
file = &dir->files[j];
}
}
// file found(?)
if(file != NULL) {
if(send_event != XWATCHER_FILE_NONE) {
// figure out the file path size
size_t filepath_size = strlen(dir->path);
filepath_size += strlen(file->name);
filepath_size += 2;
// create file path string
char *filepath = (char*)malloc(filepath_size);
snprintf(filepath, filepath_size, "%s%c%s",
dir->path, DIRBRK, file->name);
// callback
file->callback_func(send_event,
filepath,
file->context,
file->additional_data);
// free that garbage
free(filepath);
}
} else {
// Cannot find file, lets try directory
if(dir->callback_func != NULL &&
send_event != XWATCHER_FILE_NONE) {
dir->callback_func(send_event,
dir->path,
dir->context,
dir->additional_data);
}
}
// free up the converted string
free(name_char);
// Are there more events to handle?
if (event->NextEntryOffset) {
*((uint8_t**)&event) += event->NextEntryOffset;
} else {
break;
}
}
DWORD dwNotifyFilter =
FILE_NOTIFY_CHANGE_FILE_NAME |
FILE_NOTIFY_CHANGE_DIR_NAME |
FILE_NOTIFY_CHANGE_ATTRIBUTES |
FILE_NOTIFY_CHANGE_SIZE |
FILE_NOTIFY_CHANGE_LAST_WRITE |
FILE_NOTIFY_CHANGE_LAST_ACCESS |
FILE_NOTIFY_CHANGE_CREATION |
FILE_NOTIFY_CHANGE_SECURITY;
BOOL recursive = FALSE;
// Queue the next event
BOOL success = ReadDirectoryChangesW(
dir->handle,
dir->event_buffer,
BUF_LEN,
recursive,
dwNotifyFilter,
NULL,
&dir->overlapped,
NULL);
if(!success) {
// get error code
DWORD error = GetLastError();
char *message;
// get error message
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &message,
0, NULL);
fprintf(stderr, "ReadDirectoryChangesW failed: %s\n",
message);
ExitProcess(error);
}
}
// cleanup time
for(size_t i = 0; i < arr_count(watcher->directories); i++) {
struct directory *directory = &watcher->directories[i];
for(size_t j = 0; j < arr_count(directory->files); j++) {
struct file *file = &directory->files[j];
free(file->name);
}
arr_free(directory->files);
free(directory->path);
free(directory->event_buffer);
CloseHandle(directory->handle);
}
arr_free(watcher->directories);
return NULL;
}
#else
#error "Unsupported"
#endif
static inline x_watcher *xWatcher_create(void) {
x_watcher *watcher = (x_watcher*)malloc(sizeof(x_watcher));
arr_init(watcher->directories);
#if defined(__WIN32__)
// literally noop
#elif defined(__linux__)
watcher->inotify_fd = inotify_init1(O_NONBLOCK);
if(watcher->inotify_fd < 0) {
perror("inotify_init");
return NULL;
}
#else
#error "Unsupported"
#endif
return watcher;
}
static inline bool xWatcher_appendFile(
x_watcher *watcher,
xWatcher_reference *reference) {
char *path = strdup(reference->path);
// the file MUST NOT contain slashed at the end
if(path[strlen(path)-1] == DIRBRK)
return false;
char *filename = NULL;
// we need to split the filename and path
for(size_t i = strlen(path)-1; i > 0; i--) {
if(path[i] == DIRBRK) {
path[i] = '\0'; // break the string, so it splits into two
filename = &path[i+1]; // set the rest of it as the filename
break;
}
}
// If the directory is specifically local, treat it as such.
if(filename == NULL) {
filename = path;
}
struct directory *dir = NULL;
// check against the database of (pre-existing) directories
for(size_t i = 0; i < arr_count(watcher->directories); i++) {
// paths match
if(strcmp(watcher->directories[i].path, path) == 0) {
dir = &watcher->directories[i];
}
}
// directory exists, check if an callback has been already added
if(dir == NULL) {
struct directory new_dir;
new_dir.callback_func = NULL; // DO NOT add callbacks if it's a file
new_dir.context = 0; // context should be invalid as well
new_dir.additional_data = NULL; // so should the data
new_dir.path = path; // add a path to the directory
#if defined(__linux__)
new_dir.inotify_watch_fd = -1; // invalidate inotify
#elif defined(__WIN32__)
new_dir.handle = NULL;
#else
#error "Unsupported"
#endif
// initialize file arrays
arr_init(new_dir.files);
// add the directory to the masses
arr_add(watcher->directories, new_dir);
// move the pointer to the newly added element
dir = &watcher->directories[arr_count(watcher->directories)-1];
}
// search for the file
struct file *file = NULL;
for(size_t i = 0; i < arr_count(dir->files); i++) {
if(strcmp(dir->files[i].name, filename) == 0) {
file = &dir->files[i];
}
}
if(file != NULL) {
return false; // file already exists, that's an ERROR
}
struct file new_file;
// avoid an invalid free because this shares the memory space
// of the full path string
new_file.name = strdup(filename);
new_file.context = reference->context;
new_file.additional_data = reference->additional_data;
new_file.callback_func = reference->callback_func;
// the the element
arr_add(dir->files, new_file);
// and move the pointer to the newly added element
file = &dir->files[arr_count(watcher->directories)-1];
// add the file watcher
#if defined(__linux__)
if(dir->inotify_watch_fd == -1) {
dir->inotify_watch_fd = inotify_add_watch(
watcher->inotify_fd,
path,
IN_ALL_EVENTS);
if(dir->inotify_watch_fd == -1) {
perror("inotify_watch_fd");
return false;
}
}
#elif defined(__WIN32__)
// add directory path
dir->handle = CreateFile(dir->path,
FILE_LIST_DIRECTORY,
FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
NULL,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
NULL);
if(dir->handle == INVALID_HANDLE_VALUE) {
// get error code
DWORD error = GetLastError();
char *message;
// get error message
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &message,
0, NULL);
fprintf(stderr, "CreateFile failed: %s\n",
message);
return false;
}
// create event structure
dir->overlapped.hEvent = CreateEvent(NULL, FALSE, 0, NULL);
if(dir->overlapped.hEvent == NULL) {
// get error code
DWORD error = GetLastError();
char *message;
// get error message
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &message,
0, NULL);
fprintf(stderr, "CreateEvent failed: %s\n",
message);
return false;
}
// allocate the event buffer
dir->event_buffer = malloc(BUF_LEN);
if(dir->event_buffer == NULL) {
fprintf(stderr, "malloc failed at __FILE__:__LINE__!\n");
return false;
}
// set reading params
BOOL success = ReadDirectoryChangesW(
dir->handle, dir->event_buffer, BUF_LEN, TRUE,
FILE_NOTIFY_CHANGE_FILE_NAME |
FILE_NOTIFY_CHANGE_DIR_NAME |
FILE_NOTIFY_CHANGE_LAST_WRITE,
NULL, &dir->overlapped, NULL);
if(!success) {
// get error code
DWORD error = GetLastError();
char *message;
// get error message
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &message,
0, NULL);
fprintf(stderr, "ReadDirectoryChangesW failed: %s\n",
message);
return false;
}
#else
#error "Unsupported"
#endif
return true;
}
static inline bool xWatcher_appendDir(
x_watcher *watcher,
xWatcher_reference *reference) {
char *path = strdup(reference->path);
// inotify only works with directories that do NOT have a front-slash
// at the end, so we have to make sure to cut that out
if(path[strlen(path)-1] == DIRBRK)
path[strlen(path)-1] = '\0';
struct directory *dir = NULL;
// check against the database of (pre-existing) directories
for(size_t i=0; i < arr_count(watcher->directories); i++) {
// paths match
if(strcmp(watcher->directories[i].path, path) == 0) {
dir = &watcher->directories[i];
}
}
// directory exists, check if an callback has been already added
if(dir) {
// ERROR, CALLBACK EXISTS
if(dir->callback_func) {
return false;
}
dir->callback_func = reference->callback_func;
dir->context = reference->context;
dir->additional_data = reference->additional_data;
} else {
// keep an eye for this one as it's on the stack
struct directory dir;
dir.path = path;
dir.callback_func = reference->callback_func;
dir.context = reference->context;
dir.additional_data = reference->additional_data;
// initialize file arrays
arr_init(dir.files);
#if defined(__linux__)
dir.inotify_watch_fd = inotify_add_watch(
watcher->inotify_fd,
dir.path,
IN_ALL_EVENTS);
if(dir.inotify_watch_fd == -1) {
perror("inotify_watch_fd");
return false;
}
#elif defined(__WIN32__)
// add directory path
dir.handle = CreateFile(dir.path,
FILE_LIST_DIRECTORY,
FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
NULL,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
NULL);
if(dir.handle == INVALID_HANDLE_VALUE) {
// get error code
DWORD error = GetLastError();
char *message;
// get error message
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &message,
0, NULL);
fprintf(stderr, "CreateFile failed: %s\n",
message);
return false;
}
// create event structure
dir.overlapped.hEvent = CreateEvent(NULL, FALSE, 0, NULL);
if(dir.overlapped.hEvent == NULL) {
// get error code
DWORD error = GetLastError();
char *message;
// get error message
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &message,
0, NULL);
fprintf(stderr, "CreateEvent failed: %s\n",
message);
return false;
}
// allocate the event buffer
dir.event_buffer = malloc(BUF_LEN);
if(dir.event_buffer == NULL) {
fprintf(stderr, "malloc failed at __FILE__:__LINE__!\n");
return false;
}
// set reading params
BOOL success = ReadDirectoryChangesW(
dir.handle, dir.event_buffer, BUF_LEN, TRUE,
FILE_NOTIFY_CHANGE_FILE_NAME |
FILE_NOTIFY_CHANGE_DIR_NAME |
FILE_NOTIFY_CHANGE_LAST_WRITE,
NULL, &dir.overlapped, NULL);
if(!success) {
// get error code
DWORD error = GetLastError();
char *message;
// get error message
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &message,
0, NULL);
fprintf(stderr, "ReadDirectoryChangesW failed: %s\n",
message);
return false;
}
#else
#error "Unsupported"
#endif
arr_add(watcher->directories, dir);
}
return true;
}
static inline bool xWatcher_start(x_watcher *watcher) {
watcher->alive = true;
// create watcher thread
watcher->thread_id = pthread_create(
&watcher->thread,
NULL,
__internal_xWatcherProcess,
watcher);
if(watcher->thread_id != 0) {
perror("pthread_create");
watcher->alive = false;
return false;
}
return true;
}
static inline void xWatcher_destroy(x_watcher *watcher) {
void *ret;
watcher->alive = false;
pthread_join(watcher->thread, &ret);
free(watcher);
}
#endif