Change to slot-oriented nomenclature
authorSiraaj Khandkar <siraaj@khandkar.net>
Thu, 26 Mar 2020 15:48:34 +0000 (11:48 -0400)
committerSiraaj Khandkar <siraaj@khandkar.net>
Thu, 26 Mar 2020 15:48:34 +0000 (11:48 -0400)
x5/khatus.c

index 5ba94d3..382c873 100644 (file)
@@ -29,26 +29,26 @@ static const int  errlen   = sizeof(ERRMSG) - 1;
 
 char *argv0;
 
-/* TODO: Convert fifo list to fifo array. */
-typedef struct Fifo Fifo;
-struct Fifo {
-       char   *name;
-       int     fd;
-       int     width;
-       struct timespec last_read;
-       struct timespec ttl;
-       int     pos_init;  /* Initial position on the output buffer. */
-       int     pos_curr;  /* Current position on the output buffer. */
-       int     pos_final; /* Final   position on the output buffer. */
-       Fifo   *next;
+/* TODO: Convert slot list to slot array. */
+typedef struct Slot Slot;
+struct Slot {
+       char            *in_fifo;
+       int              in_fd;
+       struct timespec  in_last_read;
+       struct timespec  out_ttl;
+       int              out_width;
+       int              out_pos_lo;   /* Lowest  position on the output buffer. */
+       int              out_pos_cur;  /* Current position on the output buffer. */
+       int              out_pos_hi;   /* Highest position on the output buffer. */
+       Slot            *next;
 };
 
 typedef struct Config Config;
 struct Config {
        double interval;
        char * separator;
-       Fifo * fifos;
-       int    fifo_count;
+       Slot * slots;
+       int    slot_count;
        int    total_width;
        int    output_to_x_root_window;
 };
@@ -61,39 +61,39 @@ enum read_status {
 };
 
 void
-fifo_print_one(Fifo *f)
+slot_print_one(Slot *s)
 {
-       khlib_info("Fifo "
+       khlib_info("Slot "
            "{"
-           " name = %s,"
-           " fd = %d,"
-           " width = %d,"
-           " last_read = {tv_sec = %ld, tv_nsec = %ld}"
-           " ttl = {tv_sec = %ld, tv_nsec = %ld},"
-           " pos_init = %d,"
-           " pos_curr = %d,"
-           " pos_final = %d,"
+           " in_fifo = %s,"
+           " in_fd = %d,"
+           " out_width = %d,"
+           " in_last_read = {tv_sec = %ld, tv_nsec = %ld}"
+           " out_ttl = {tv_sec = %ld, tv_nsec = %ld},"
+           " out_pos_lo = %d,"
+           " out_pos_cur = %d,"
+           " out_pos_hi = %d,"
            " next = %p,"
            " }\n",
-           f->name,
-           f->fd,
-           f->width,
-           f->last_read.tv_sec,
-           f->last_read.tv_nsec,
-           f->ttl.tv_sec,
-           f->ttl.tv_nsec,
-           f->pos_init,
-           f->pos_curr,
-           f->pos_final,
-           f->next
+           s->in_fifo,
+           s->in_fd,
+           s->out_width,
+           s->in_last_read.tv_sec,
+           s->in_last_read.tv_nsec,
+           s->out_ttl.tv_sec,
+           s->out_ttl.tv_nsec,
+           s->out_pos_lo,
+           s->out_pos_cur,
+           s->out_pos_hi,
+           s->next
        );
 }
 
 void
-fifo_print_all(Fifo *head)
+slot_print_all(Slot *head)
 {
-       for (Fifo *f = head; f; f = f->next) {
-               fifo_print_one(f);
+       for (Slot *s = head; s; s = s->next) {
+               slot_print_one(s);
        }
 }
 
@@ -105,34 +105,34 @@ config_print(Config *cfg)
            "{"
            " interval = %f,"
            " separator = %s,"
-           " fifo_count = %d,"
+           " slot_count = %d,"
            " total_width = %d,"
-           " fifos = ..."
+           " slots = ..."
            " }\n",
            cfg->interval,
            cfg->separator,
-           cfg->fifo_count,
+           cfg->slot_count,
            cfg->total_width
        );
-       fifo_print_all(cfg->fifos);
+       slot_print_all(cfg->slots);
 }
 
 int
-is_pos_num(char *s)
+is_pos_num(char *str)
 {
-       while (*s != '\0')
-               if (!isdigit(*(s++)))
+       while (*str != '\0')
+               if (!isdigit(*(str++)))
                        return 0;
        return 1;
 }
 
 int
-is_decimal(char *s)
+is_decimal(char *str)
 {
        char c;
        int seen = 0;
 
-       while ((c = *(s++)) != '\0')
+       while ((c = *(str++)) != '\0')
                if (!isdigit(c)) {
                        if (c == '.' && !seen++)
                                continue;
@@ -262,29 +262,29 @@ parse_opts_spec(Config *cfg, int argc, char *argv[], int i)
        char *w = argv[i++];
        char *t = argv[i++];
 
-       struct timespec last_read;
+       struct timespec in_last_read;
 
        if (!is_pos_num(w))
                usage("[spec] Invalid width: \"%s\", for fifo \"%s\"\n", w, n);
        if (!is_decimal(t))
                usage("[spec] Invalid TTL: \"%s\", for fifo \"%s\"\n", t, n);
-       last_read.tv_sec  = 0;
-       last_read.tv_nsec = 0;
-       Fifo *f = calloc(1, sizeof(struct Fifo));
-       if (f) {
-               f->name      = n;
-               f->fd        = -1;
-               f->width     = atoi(w);
-               f->ttl       = khlib_timespec_of_float(atof(t));
-               f->last_read = last_read;
-               f->pos_init  = cfg->total_width;
-               f->pos_curr  = f->pos_init;
-               f->pos_final = f->pos_init + f->width - 1;
-               f->next      = cfg->fifos;
-
-               cfg->fifos        = f;
-               cfg->total_width += f->width;
-               cfg->fifo_count++;
+       in_last_read.tv_sec  = 0;
+       in_last_read.tv_nsec = 0;
+       Slot *s = calloc(1, sizeof(struct Slot));
+       if (s) {
+               s->in_fifo      = n;
+               s->in_fd        = -1;
+               s->out_width     = atoi(w);
+               s->out_ttl       = khlib_timespec_of_float(atof(t));
+               s->in_last_read = in_last_read;
+               s->out_pos_lo  = cfg->total_width;
+               s->out_pos_cur  = s->out_pos_lo;
+               s->out_pos_hi = s->out_pos_lo + s->out_width - 1;
+               s->next      = cfg->slots;
+
+               cfg->slots        = s;
+               cfg->total_width += s->out_width;
+               cfg->slot_count++;
        } else {
                khlib_fatal("[memory] Allocation failure.");
        }
@@ -310,57 +310,59 @@ opts_parse(Config *cfg, int argc, char *argv[])
 {
        opts_parse_any(cfg, argc, argv, 1);
 
-       Fifo *last = cfg->fifos;
-       cfg->fifos = NULL;
-       for (Fifo *f = last; f; ) {
-               Fifo *next = f->next;
-               f->next = cfg->fifos;
-               cfg->fifos = f;
-               f = next;
+       Slot *last = cfg->slots;
+       cfg->slots = NULL;
+       for (Slot *s = last; s; ) {
+               Slot *next = s->next;
+               s->next = cfg->slots;
+               cfg->slots = s;
+               s = next;
        }
 }
 
 void
-fifo_expire(Fifo *f, struct timespec t, char *buf)
+slot_expire(Slot *s, struct timespec t, char *buf)
 {
        struct timespec td;
 
-       timespecsub(&t, &(f->last_read), &td);
-       if (timespeccmp(&td, &(f->ttl), >=)) {
+       timespecsub(&t, &(s->in_last_read), &td);
+       if (timespeccmp(&td, &(s->out_ttl), >=)) {
                /* TODO: Maybe configurable expiry character. */
-               memset(buf + f->pos_init, '_', f->pos_final - f->pos_init);
-               khlib_warn("Data source expired: \"%s\"\n", f->name);
+               memset(buf + s->out_pos_lo, '_', s->out_pos_hi - s->out_pos_lo);
+               khlib_warn("Slot expired: \"%s\"\n", s->in_fifo);
        }
 }
 
 void
-fifo_read_error(Fifo *f, char *buf)
+slot_read_error(Slot *s, char *buf)
 {
        char *b;
        int i;
 
-       b = buf + f->pos_init;
+       b = buf + s->out_pos_lo;
        /* Copy as much of the error message as possible.
         * EXCLUDING the terminating \0. */
-       for (i = 0; i < errlen && i < f->width; i++)
+       for (i = 0; i < errlen && i < s->out_width; i++)
                b[i] = errmsg[i];
        /* Any remaining slots: */
-       for (; i < f->width; i++)
+       for (; i < s->out_width; i++)
                b[i] = '_';
 }
 
 enum read_status
-fifo_read_one(Fifo *f, struct timespec t, char *buf)
+slot_read_one(Slot *s, struct timespec t, char *buf)
 {
        char c;  /* Character read. */
        int  r;  /* Remaining unused slots in buffer range. */
 
        for (;;) {
-               switch (read(f->fd, &c, 1)) {
+               switch (read(s->in_fd, &c, 1)) {
                case -1:
                        khlib_error(
                            "Failed to read: \"%s\". errno: %d, msg: %s\n",
-                           f->name, errno, strerror(errno)
+                           s->in_fifo,
+                           errno,
+                           strerror(errno)
                        );
                        switch (errno) {
                        case EINTR:
@@ -370,21 +372,21 @@ fifo_read_one(Fifo *f, struct timespec t, char *buf)
                                return FAILURE;
                        }
                case  0:
-                       khlib_debug("%s: End of FILE\n", f->name);
-                       f->pos_curr = f->pos_init;
+                       khlib_debug("%s: End of FILE\n", s->in_fifo);
+                       s->out_pos_cur = s->out_pos_lo;
                        return END_OF_FILE;
                case  1:
                        /* TODO: Consider making msg term char a CLI option */
                        if (c == '\n' || c == '\0') {
-                               r = f->pos_final - f->pos_curr;
+                               r = s->out_pos_hi - s->out_pos_cur;
                                if (r > 0)
-                                       memset(buf + f->pos_curr, ' ', r);
-                               f->pos_curr = f->pos_init;
-                               f->last_read = t;
+                                       memset(buf + s->out_pos_cur, ' ', r);
+                               s->out_pos_cur = s->out_pos_lo;
+                               s->in_last_read = t;
                                return END_OF_MESSAGE;
                        } else {
-                               if (f->pos_curr <= f->pos_final)
-                                       buf[f->pos_curr++] = c;
+                               if (s->out_pos_cur <= s->out_pos_hi)
+                                       buf[s->out_pos_cur++] = c;
                                /* Drop beyond available range. */
                                /*
                                 * TODO Define max after which we stop reading.
@@ -400,7 +402,7 @@ fifo_read_one(Fifo *f, struct timespec t, char *buf)
 }
 
 void
-fifo_read_all(Config *cfg, struct timespec *ti, char *buf)
+slot_read_all(Config *cfg, struct timespec *ti, char *buf)
 {
        fd_set fds;
        int maxfd = -1;
@@ -409,46 +411,46 @@ fifo_read_all(Config *cfg, struct timespec *ti, char *buf)
        struct timespec t;
 
        FD_ZERO(&fds);
-       for (Fifo *f = cfg->fifos; f; f = f->next) {
+       for (Slot *s = cfg->slots; s; s = s->next) {
                /* TODO: Create the FIFO if it doesn't already exist. */
-               if (lstat(f->name, &st) < 0) {
+               if (lstat(s->in_fifo, &st) < 0) {
                        khlib_error(
                            "Cannot stat \"%s\". Error: %s\n",
-                           f->name,
+                           s->in_fifo,
                            strerror(errno)
                        );
-                       fifo_read_error(f, buf);
+                       slot_read_error(s, buf);
                        continue;
                }
                if (!(st.st_mode & S_IFIFO)) {
-                       khlib_error("\"%s\" is not a FIFO\n", f->name);
-                       fifo_read_error(f, buf);
+                       khlib_error("\"%s\" is not a FIFO\n", s->in_fifo);
+                       slot_read_error(s, buf);
                        continue;
                }
-               if (f->fd < 0) {
+               if (s->in_fd < 0) {
                        khlib_debug(
-                           "%s: closed. opening. fd: %d\n",
-                           f->name,
-                           f->fd
+                           "%s: closed. opening. in_fd: %d\n",
+                           s->in_fifo,
+                           s->in_fd
                        );
-                       f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
+                       s->in_fd = open(s->in_fifo, O_RDONLY | O_NONBLOCK);
                } else {
                        khlib_debug(
-                           "%s: already openned. fd: %d\n",
-                           f->name,
-                           f->fd
+                           "%s: already openned. in_fd: %d\n",
+                           s->in_fifo,
+                           s->in_fd
                        );
                }
-               if (f->fd == -1) {
-                       /* TODO Consider backing off retries for failed fifos */
-                       khlib_error("Failed to open \"%s\"\n", f->name);
-                       fifo_read_error(f, buf);
+               if (s->in_fd == -1) {
+                       /* TODO Consider backing off retries for failed slots */
+                       khlib_error("Failed to open \"%s\"\n", s->in_fifo);
+                       slot_read_error(s, buf);
                        continue;
                }
-               khlib_debug("%s: open. fd: %d\n", f->name, f->fd);
-               if (f->fd > maxfd)
-                       maxfd = f->fd;
-               FD_SET(f->fd, &fds);
+               khlib_debug("%s: open. in_fd: %d\n", s->in_fifo, s->in_fd);
+               if (s->in_fd > maxfd)
+                       maxfd = s->in_fd;
+               FD_SET(s->in_fd, &fds);
        }
        khlib_debug("selecting...\n");
        ready = pselect(maxfd + 1, &fds, NULL, NULL, ti, NULL);
@@ -476,10 +478,10 @@ fifo_read_all(Config *cfg, struct timespec *ti, char *buf)
        }
        /* At-least-once ensures that expiries are still checked on timeouts. */
        do {
-               for (Fifo *f = cfg->fifos; f; f = f->next) {
-                       if (FD_ISSET(f->fd, &fds)) {
-                               khlib_debug("reading: %s\n", f->name);
-                               switch (fifo_read_one(f, t, buf)) {
+               for (Slot *s = cfg->slots; s; s = s->next) {
+                       if (FD_ISSET(s->in_fd, &fds)) {
+                               khlib_debug("reading: %s\n", s->in_fifo);
+                               switch (slot_read_one(s, t, buf)) {
                                /*
                                 * ### MESSAGE LOSS ###
                                 * is introduced by closing at EOM in addition
@@ -497,8 +499,8 @@ fifo_read_all(Config *cfg, struct timespec *ti, char *buf)
                                case END_OF_MESSAGE:
                                case END_OF_FILE:
                                case FAILURE:
-                                       close(f->fd);
-                                       f->fd = -1;
+                                       close(s->in_fd);
+                                       s->in_fd = -1;
                                        ready--;
                                        break;
                                case RETRY:
@@ -507,7 +509,7 @@ fifo_read_all(Config *cfg, struct timespec *ti, char *buf)
                                        assert(0);
                                }
                        } else {
-                               fifo_expire(f, t, buf);
+                               slot_expire(s, t, buf);
                        }
                }
        } while (ready);
@@ -520,14 +522,14 @@ main(int argc, char *argv[])
        Config cfg = {
                .interval    = 1.0,
                .separator   = "|",
-               .fifos       = NULL,
-               .fifo_count  = 0,
+               .slots       = NULL,
+               .slot_count  = 0,
                .total_width = 0,
                .output_to_x_root_window = 0,
        };
 
        int width  = 0;
-       int nfifos = 0;
+       int nslots = 0;
        int seplen = 0;
        int prefix = 0;
        int errors = 0;
@@ -535,8 +537,8 @@ main(int argc, char *argv[])
        Display *d = NULL;
        struct stat st;
        struct timespec
-               t0,  /* time stamp. before reading fifos */
-               t1,  /* time stamp. after  reading fifos */
+               t0,  /* time stamp. before reading slots */
+               t1,  /* time stamp. after  reading slots */
                ti,  /* time interval desired    (t1 - t0) */
                td,  /* time interval measured   (t1 - t0) */
                tc;  /* time interval correction (ti - td) when td < ti */
@@ -549,22 +551,22 @@ main(int argc, char *argv[])
 
        ti = khlib_timespec_of_float(cfg.interval);
 
-       if (cfg.fifos == NULL)
-               usage("No fifo specs were given!\n");
+       if (cfg.slots == NULL)
+               usage("No slot specs were given!\n");
 
        /* 1st pass to check file existence and type */
-       for (Fifo *f = cfg.fifos; f; f = f->next) {
-               if (lstat(f->name, &st) < 0) {
+       for (Slot *s = cfg.slots; s; s = s->next) {
+               if (lstat(s->in_fifo, &st) < 0) {
                        khlib_error(
                            "Cannot stat \"%s\". Error: %s\n",
-                           f->name,
+                           s->in_fifo,
                            strerror(errno)
                        );
                        errors++;
                        continue;
                }
                if (!(st.st_mode & S_IFIFO)) {
-                       khlib_error("\"%s\" is not a FIFO\n", f->name);
+                       khlib_error("\"%s\" is not a FIFO\n", s->in_fifo);
                        errors++;
                        continue;
                }
@@ -578,14 +580,14 @@ main(int argc, char *argv[])
        seplen = strlen(cfg.separator);
 
        /* 2nd pass to make space for separators */
-       for (Fifo *f = cfg.fifos; f; f = f->next) {
-               f->pos_init  += prefix;
-               f->pos_final += prefix;
-               f->pos_curr = f->pos_init;
+       for (Slot *s = cfg.slots; s; s = s->next) {
+               s->out_pos_lo  += prefix;
+               s->out_pos_hi += prefix;
+               s->out_pos_cur = s->out_pos_lo;
                prefix += seplen;
-               nfifos++;
+               nslots++;
        }
-       width += (seplen * (nfifos - 1));
+       width += (seplen * (nslots - 1));
        buf = calloc(1, width + 1);
        if (buf == NULL)
                khlib_fatal(
@@ -595,11 +597,11 @@ main(int argc, char *argv[])
        memset(buf, ' ', width);
        buf[width] = '\0';
        /* 3rd pass to set the separators */
-       for (Fifo *f = cfg.fifos; f; f = f->next) {
-               if (f->pos_init) {  /* Skip the first, left-most */
+       for (Slot *s = cfg.slots; s; s = s->next) {
+               if (s->out_pos_lo) {  /* Skip the first, left-most */
                        /* Copying only seplen ensures we omit the '\0' byte. */
                        strncpy(
-                           buf + (f->pos_init - seplen),
+                           buf + (s->out_pos_lo - seplen),
                            cfg.separator,
                            seplen
                        );
@@ -611,7 +613,7 @@ main(int argc, char *argv[])
        /* TODO: Handle signals */
        for (;;) {
                clock_gettime(CLOCK_MONOTONIC, &t0); // FIXME: check errors
-               fifo_read_all(&cfg, &ti, buf);
+               slot_read_all(&cfg, &ti, buf);
                if (cfg.output_to_x_root_window) {
                        if (XStoreName(d, DefaultRootWindow(d), buf) < 0)
                                khlib_fatal("XStoreName failed.\n");
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