init LocCorr - grasshopper CMOS & pusirobot motors based corrector

LocCorr/inotify.c

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+/*
+ * This file is part of the loccorr project.
+ * Copyright 2021 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h> // strlen
+#include <sys/inotify.h>
+#include <sys/select.h>
+#include <unistd.h>
+#include <usefull_macros.h>
+
+#include "imagefile.h"
+
+static char filenm[FILENAME_MAX];
+
+// handle inotify event IN_CLOSE_WRITE
+/**
+ * @brief handle_events - handle inotify event IN_CLOSE_WRITE
+ * @param name  - directory or file name
+ * @param fd    - inotify init descriptor
+ * @return 1 if file was changed and ready to be processed, 0 if not changed, -1 if removed
+ */
+static int changed(const char *name, int fd, uint32_t mask){
+    struct inotify_event buf[10] = {0};
+    ssize_t len = read(fd, buf, sizeof buf);
+    if(len == -1 && errno != EAGAIN){
+        WARN("inotify read()");
+        return -1;
+    }
+    if(len < 1) return 0; // not ready
+    uint32_t bm = buf[0].mask;
+    buf[0].mask = 0;
+    for(int i = 0; i < 10; ++i)
+        DBG("CHANGED: %s (%d)\n", buf[i].name, bm);
+    if(bm & mask){
+        if(name){
+            snprintf(filenm, FILENAME_MAX, "%s/%s", name, buf[0].name); // full path
+        }else{
+            snprintf(filenm, FILENAME_MAX, "%s", buf[0].name); // file name
+        }
+        return 1;
+    }
+    DBG("IN_IGNORED");
+    return -1; // IN_IGNORED (file removed)
+}
+
+static int initinot(const char *name, int *filed, uint32_t mask){
+    static int fd = -1, wd = -1;
+    if(wd > -1){
+        inotify_rm_watch(fd, wd);
+        wd = -1; fd = -1;
+    }
+    if(fd == -1) fd = inotify_init();//1(IN_NONBLOCK);
+    if(fd == -1){
+       WARN("inotify_init()");
+       return 0;
+    }
+    if(-1 == (wd = inotify_add_watch(fd, name, mask))){
+        WARN("inotify_add_watch()");
+        return 0;
+    }
+    if(filed) *filed = fd;
+    return wd;
+}
+
+static int watch_any(const char *name, void (*process)(Image*), uint32_t mask){
+    int fd = -1, wd = -1;
+    while(1){
+        if(wd < 1 || fd < 1){
+            wd = initinot(name, &fd, mask);
+            if(wd < 1){
+                usleep(1000);
+                continue;
+            }
+        }
+        int ch;
+        if(mask == IN_CLOSE_WRITE)
+            ch = changed(NULL, fd, mask); // only file name
+        else
+            ch = changed(name, fd, mask); // full path
+        if(ch == -1){ sleep(1); wd = -1; continue; } // removed
+        if(ch == 1){ // changed
+            if(process){
+                Image *I = Image_read(filenm);
+                process(I);
+            }
+        }
+    }
+    close(fd);
+    return 0;
+}
+
+
+
+int watch_file(const char *name, void (*process)(Image*)){
+    FNAME();
+    if(!name){
+        WARNX("Need filename");
+        return 1;
+    }
+    return watch_any(name, process, IN_CLOSE_WRITE);
+}
+
+int watch_directory(char *name, void (*process)(Image*)){
+    FNAME();
+    if(!name){
+        WARNX("Need directory name");
+        return 1;
+    }
+    int l = strlen(name) - 1;
+    if(name[l] == '/') name[l] = 0;
+    return watch_any(name, process, IN_CLOSE_WRITE|IN_ISDIR);
+}