Create a "utils" module

Also put configuration macros in a dedicated header. In the future the
configuration will be read at execution time.

5 files changed, 166 insertions, 125 deletions

diff --git a/Makefile b/Makefile
index c20fb08..adec8b4 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ export __LIBS   := $(shell pkg-config --libs sqlite3)
 
 all: $(PROG)
 
-$(PROG): src/main.o src/system.o
+$(PROG): src/main.o src/system.o src/utils.o
 	$(CC) -o $@ $^ $(__LIBS) $(LDFLAGS) $(LIBS)
 # Create cache and config directories at compile time since they will be used by
 # the user who compiled ftag
@@ -35,8 +35,9 @@ $(PROG): src/main.o src/system.o
 	mkdir -p $(FTAG_CACHE_DIR)
 	mkdir -p $(FTAG_CONFIG_DIR)
 
-src/main.o: src/main.c src/system.h
+src/main.o: src/main.c src/system.h src/utils.h
 src/system.o: src/system.c src/system.h
+src/utils.o: src/utils.c src/system.h src/utils.h
 .c.o:
 	$(CC) $(__CFLAGS) $(CFLAGS) -o $@ -c $<
 
diff --git a/src/config.h b/src/config.h
new file mode 100644
index 0000000..82ffd6a
--- /dev/null
+++ b/src/config.h
@@ -0,0 +1,15 @@
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#ifndef FTAG_REMOTE_HOST
+#define FTAG_REMOTE_HOST "localhost"
+#endif
+
+#ifndef FTAG_REMOTE_ROOT
+/* HOME on remote host */
+#define FTAG_REMOTE_ROOT "ftag"
+#endif
+
+#define DATABASE_PATH FTAG_CACHE_DIR "/ftag.sqlite3"
+
+#endif
diff --git a/src/main.c b/src/main.c
index 2976931..a8e4176 100644
--- a/src/main.c
+++ b/src/main.c
@@ -10,18 +10,9 @@
 #include <time.h>
 #include <unistd.h>
 
+#include "config.h"
 #include "system.h"
-
-#ifndef FTAG_REMOTE_HOST
-#define FTAG_REMOTE_HOST "localhost"
-#endif
-
-#ifndef FTAG_REMOTE_ROOT
-/* HOME on remote host */
-#define FTAG_REMOTE_ROOT "ftag"
-#endif
-
-#define DATABASE_PATH FTAG_CACHE_DIR "/ftag.sqlite3"
+#include "utils.h"
 
 /* TODO: read the configuration from a file
 
@@ -62,23 +53,6 @@ static void __sqlite3_check(int rc, sqlite3 *db, const char *file, int line, con
 #define sqlite3_check(RC, DB) \
 	__sqlite3_check(RC, DB, __FILE__, __LINE__, __func__)
 
-static void assert_db_exists(void)
-{
-	if (file_exists(DATABASE_PATH))
-		return;
-
-	if (errno == ENOENT) {
-		fprintf(stderr,
-			"ftag: database not found at \"%s\", "
-			"have you run \"ftag init\"?\n",
-			DATABASE_PATH);
-	}
-	else {
-		perror(DATABASE_PATH);
-	}
-	exit(EXIT_FAILURE);
-}
-
 /* Prompt the user for yes or no (default is yes). Before calling, a prompt
  * should be printed to stdout, eventually not with an ending newline. */
 static int prompt_yes_no(void)
@@ -135,101 +109,6 @@ static void sanitize_sql_str(char **str)
 	*str = new_str;
 }
 
-/* Safely create a formatted string and write it to BUF. BUF shall be a buffer
- * of size at least SIZE. BUF can be stack-allocated. If the formatting cannot
- * be performed, exit(3) is called. This function is not meant to be called
- * directly: the macro strbuild should be used. The code is adapted from the
- * make_message function of the vsnprintf(3) manual page, section "examples". */
-static void __strbuild(char *buf, int size,
-		       const char *file, int line,
-		       const char *fmt, ...)
-{
-	va_list ap;
-	int len;
-
-	va_start(ap, fmt);
-	len = vsnprintf(NULL, 0, fmt, ap);
-	va_end(ap);
-
-	if (len < 0) {
-		fprintf(stderr, "%s:%d: ", file, line);
-		perror("");
-		exit(EXIT_FAILURE);
-	}
-	if (len >= size) {
-		fprintf(stderr, "%s:%d: error: not enough space, "
-			"have %d, need at least %d\n",
-			file, line,
-			size, len + 1);
-		exit(EXIT_FAILURE);
-	}
-
-	va_start(ap, fmt);
-	len = vsnprintf(buf, size, fmt, ap);
-	va_end(ap);
-
-	assert(len >= 0);
-}
-
-/* Convenience wrappers for __strbuild. */
-#define strbuild(buf, fmt, ...) \
-	__strbuild(buf, sizeof(buf), __FILE__, __LINE__, fmt, __VA_ARGS__)
-#define strbuild_with_size(buf, size, fmt, ...)				\
-	__strbuild(buf, size, __FILE__, __LINE__, fmt, __VA_ARGS__)
-
-static int str_has_suffix(const char *str, const char *suffix)
-{
-	int str_len = strlen(str);
-	int suffix_len = strlen(suffix);
-	return ((str_len > suffix_len)
-		&& (strcmp(str + str_len - suffix_len, suffix) == 0));
-}
-
-/* Compute something that identifies the content of FILE. Algorithm by Dan
- * Bernstein from http://www.cse.yorku.ca/~oz/hash.html via
- * https://stackoverflow.com/a/7666577/20138083. */
-static uint32_t sum(const char *file)
-{
-	FILE *stream = fopen(file, "r");
-	uint8_t buf[4096];
-	size_t buf_len;
-	uint32_t sum = 5381;
-	if (!file) {
-		fprintf(stderr, "fopen: \"%s\": ", file);
-		perror("");
-		exit(EXIT_FAILURE);
-	}
-	while ((buf_len = fread(&buf, 1, sizeof(buf), stream)) != 0) {
-		for (int i = 0; i < buf_len; i++) {
-			uint8_t next = buf[i];
-			sum = sum*33 + next;
-		}
-	}
-	if (ferror(stream)) {
-		fprintf(stderr, "fread: \"%s\": ", file);
-		perror("");
-		exit(EXIT_FAILURE);
-	}
-	fclose(stream);
-	return sum;
-}
-
-/* Return an integer timestamp from a date string of the format YYYY-MM-DD. */
-static time_t time_from_str(const char *str)
-{
-	int rc;
-	struct tm tm;
-	memset(&tm, 0, sizeof(tm));
-	rc = sscanf(str, "%d-%d-%d", &tm.tm_year, &tm.tm_mon, &tm.tm_mday);
-	if (rc <= 0) {
-		perror("sscanf");
-		exit(EXIT_FAILURE);
-	}
-	tm.tm_year -= 1900;
-	tm.tm_mon -= 1;
-	return mktime(&tm);
-}
-
 /* Write an id to *_ID, used by table_next_id. Write -1 if no id is found. */
 static int table_next_id_callback(void *_id, int, char **cols, char **)
 {
diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..a1fc5b9
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,107 @@
+#include <assert.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "config.h"
+#include "system.h"
+#include "utils.h"
+
+void __strbuild(char *buf, int size,
+		const char *file, int line,
+		const char *fmt, ...)
+{
+	va_list ap;
+	int len;
+
+	va_start(ap, fmt);
+	len = vsnprintf(NULL, 0, fmt, ap);
+	va_end(ap);
+
+	if (len < 0) {
+		fprintf(stderr, "%s:%d: ", file, line);
+		perror("");
+		exit(EXIT_FAILURE);
+	}
+	if (len >= size) {
+		fprintf(stderr, "%s:%d: error: not enough space, "
+			"have %d, need at least %d\n",
+			file, line,
+			size, len + 1);
+		exit(EXIT_FAILURE);
+	}
+
+	va_start(ap, fmt);
+	len = vsnprintf(buf, size, fmt, ap);
+	va_end(ap);
+
+	assert(len >= 0);
+}
+
+int str_has_suffix(const char *str, const char *suffix)
+{
+	int str_len = strlen(str);
+	int suffix_len = strlen(suffix);
+	return ((str_len > suffix_len)
+		&& (strcmp(str + str_len - suffix_len, suffix) == 0));
+}
+
+void assert_db_exists(void)
+{
+	if (file_exists(DATABASE_PATH))
+		return;
+
+	if (errno == ENOENT) {
+		fprintf(stderr,
+			"ftag: database not found at \"%s\", "
+			"have you run \"ftag init\"?\n",
+			DATABASE_PATH);
+	}
+	else {
+		perror(DATABASE_PATH);
+	}
+	exit(EXIT_FAILURE);
+}
+
+uint32_t sum(const char *file)
+{
+	FILE *stream = fopen(file, "r");
+	uint8_t buf[4096];
+	size_t buf_len;
+	uint32_t sum = 5381;
+	if (!file) {
+		fprintf(stderr, "fopen: \"%s\": ", file);
+		perror("");
+		exit(EXIT_FAILURE);
+	}
+	while ((buf_len = fread(&buf, 1, sizeof(buf), stream)) != 0) {
+		for (int i = 0; i < buf_len; i++) {
+			uint8_t next = buf[i];
+			sum = sum*33 + next;
+		}
+	}
+	if (ferror(stream)) {
+		fprintf(stderr, "fread: \"%s\": ", file);
+		perror("");
+		exit(EXIT_FAILURE);
+	}
+	fclose(stream);
+	return sum;
+}
+
+time_t time_from_str(const char *str)
+{
+	int rc;
+	struct tm tm;
+	memset(&tm, 0, sizeof(tm));
+	rc = sscanf(str, "%d-%d-%d", &tm.tm_year, &tm.tm_mon, &tm.tm_mday);
+	if (rc <= 0) {
+		perror("sscanf");
+		exit(EXIT_FAILURE);
+	}
+	tm.tm_year -= 1900;
+	tm.tm_mon -= 1;
+	return mktime(&tm);
+}
diff --git a/src/utils.h b/src/utils.h
new file mode 100644
index 0000000..e382ace
--- /dev/null
+++ b/src/utils.h
@@ -0,0 +1,39 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+/* Utility functions for manipulating strings, time, and error codes. */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <time.h>
+
+/* Internals of strbuild. */
+void __strbuild(char *buf, int size,
+		const char *file, int line,
+		const char *fmt, ...);
+
+/* Safely create a formatted string and write it to BUF. BUF shall be a buffer
+ * of size at least SIZE. BUF can be stack-allocated. If the formatting cannot
+ * be performed, exit(3) is called. This function is not meant to be called
+ * directly: the macro strbuild should be used. The code is adapted from the
+ * make_message function of the vsnprintf(3) manual page, section "examples". */
+#define strbuild(buf, fmt, ...) \
+	__strbuild(buf, sizeof(buf), __FILE__, __LINE__, fmt, __VA_ARGS__)
+
+#define strbuild_with_size(buf, size, fmt, ...)				\
+	__strbuild(buf, size, __FILE__, __LINE__, fmt, __VA_ARGS__)
+
+int str_has_suffix(const char *str, const char *suffix);
+
+/* Abort if the database does not exist. */
+void assert_db_exists(void);
+
+/* Compute something that identifies the content of FILE. Algorithm by Dan
+ * Bernstein from http://www.cse.yorku.ca/~oz/hash.html via
+ * https://stackoverflow.com/a/7666577/20138083. */
+uint32_t sum(const char *file);
+
+/* Return an integer timestamp from a date string of the format YYYY-MM-DD. */
+time_t time_from_str(const char *str);
+
+#endif