dmenu/patch/navhistory.c

static char *histfile;
static char **history;
static size_t histsz, histpos;

static void
loadhistory(void)
{
	FILE *fp = NULL;
	static size_t cap = 0;
	size_t llen;
	char *line;

	if (!histfile) {
		return;
	}

	fp = fopen(histfile, "r");
	if (!fp) {
		return;
	}

	for (;;) {
		line = NULL;
		llen = 0;
		if (-1 == getline(&line, &llen, fp)) {
			if (ferror(fp)) {
				die("failed to read history");
			}
			free(line);
			break;
		}

		if (cap == histsz) {
			cap += 64 * sizeof(char*);
			history = realloc(history, cap);
			if (!history) {
				die("failed to realloc memory");
			}
		}
		strtok(line, "\n");
		history[histsz] = line;
		histsz++;
	}
	histpos = histsz;

	if (fclose(fp)) {
		die("failed to close file %s", histfile);
	}
}

static void
navhistory(int dir)
{
	static char def[BUFSIZ];
	char *p = NULL;
	size_t len = 0;

	if (!history || histpos + 1 == 0)
		return;

	if (histsz == histpos) {
		strncpy(def, text, sizeof(def));
	}

	switch(dir) {
	case 1:
		if (histpos < histsz - 1) {
			p = history[++histpos];
		} else if (histpos == histsz - 1) {
			p = def;
			histpos++;
		}
		break;
	case -1:
		if (histpos > 0) {
			p = history[--histpos];
		}
		break;
	}
	if (p == NULL) {
		return;
	}

	len = MIN(strlen(p), BUFSIZ - 1);
	strncpy(text, p, len);
	text[len] = '\0';
	cursor = len;
	match();
}

static void
savehistory(char *input)
{
	unsigned int i;
	FILE *fp;

	if (!histfile ||
	    0 == maxhist ||
	    0 == strlen(input)) {
		goto out;
	}

	fp = fopen(histfile, "w");
	if (!fp) {
		die("failed to open %s", histfile);
	}
	for (i = histsz < maxhist ? 0 : histsz - maxhist; i < histsz; i++) {
		if (0 >= fprintf(fp, "%s\n", history[i])) {
			die("failed to write to %s", histfile);
		}
	}
	if (histsz == 0 || !histnodup || (histsz > 0 && strcmp(input, history[histsz-1]) != 0)) { /* TODO */
		if (0 >= fputs(input, fp)) {
			die("failed to write to %s", histfile);
		}
	}
	if (fclose(fp)) {
		die("failed to close file %s", histfile);
	}

out:
	for (i = 0; i < histsz; i++) {
		free(history[i]);
	}
	free(history);
}