Use a shared input/output mutex

Replace the save mutex with a common mutex, which is locked whenever
read or write operations on the data files are performed. Also, since
this mutex is an implementation detail, mark the locking functions
static and remove them from the header file.

Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

2 files changed, 23 insertions, 16 deletions

diff --git a/src/calcurse.h b/src/calcurse.h
index 5fa4639..59b46b5 100644
--- a/src/calcurse.h
+++ b/src/calcurse.h
@@ -836,8 +836,6 @@ void ical_export_data(FILE *, int);
 unsigned io_fprintln(const char *, const char *, ...);
 void io_init(const char *, const char *);
 void io_extract_data(char *, const char *, int);
-void io_save_mutex_lock(void);
-void io_save_mutex_unlock(void);
 void io_dump_apts(const char *, const char *, const char *, const char *);
 unsigned io_save_apts(const char *);
 void io_dump_todo(const char *);
diff --git a/src/io.c b/src/io.c
index 0cefa9c..600993b 100644
--- a/src/io.c
+++ b/src/io.c
@@ -286,16 +286,16 @@ void io_extract_data(char *dst_data, const char *org, int len)
 	*dst_data = '\0';
 }
 
-static pthread_mutex_t io_save_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t io_mutex = PTHREAD_MUTEX_INITIALIZER;
 
-void io_save_mutex_lock(void)
+static void io_mutex_lock(void)
 {
-	pthread_mutex_lock(&io_save_mutex);
+	pthread_mutex_lock(&io_mutex);
 }
 
-void io_save_mutex_unlock(void)
+static void io_mutex_unlock(void)
 {
-	pthread_mutex_unlock(&io_save_mutex);
+	pthread_mutex_unlock(&io_mutex);
 }
 
 /* Print all appointments and events to stdout. */
@@ -434,10 +434,10 @@ static void io_merge_data(void)
 	asprintf(&path_apts_new, "%s%s", path_apts, new_ext);
 	asprintf(&path_todo_new, "%s%s", path_todo, new_ext);
 
-	io_save_mutex_lock();
+	io_mutex_lock();
 	io_save_apts(path_apts_new);
 	io_save_todo(path_todo_new);
-	io_save_mutex_unlock();
+	io_mutex_unlock();
 
 	/*
 	 * We do not directly write to the data files here; however, the
@@ -504,22 +504,29 @@ static int io_check_data_files_modified()
 {
 	FILE *fp;
 	char sha1_new[SHA1_DIGESTLEN * 2 + 1];
+	int ret = 1;
+
+	io_mutex_lock();
 
 	if ((fp = fopen(path_apts, "r"))) {
 		sha1_stream(fp, sha1_new);
 		fclose(fp);
 		if (strncmp(sha1_new, apts_sha1, SHA1_DIGESTLEN * 2) != 0)
-			return 1;
+			goto cleanup;
 	}
 
 	if ((fp = fopen(path_todo, "r"))) {
 		sha1_stream(fp, sha1_new);
 		fclose(fp);
 		if (strncmp(sha1_new, todo_sha1, SHA1_DIGESTLEN * 2) != 0)
-			return 1;
+			goto cleanup;
 	}
 
-	return 0;
+	ret = 0;
+
+cleanup:
+	io_mutex_unlock();
+	return ret;
 }
 
 /* Save the calendar data */
@@ -538,7 +545,7 @@ void io_save_cal(enum save_display display)
 		return;
 
 	run_hook("pre-save");
-	pthread_mutex_lock(&io_save_mutex);
+	io_mutex_lock();
 
 	show_bar = 0;
 	if (ui_mode == UI_CURSES && display == IO_SAVE_DISPLAY_BAR
@@ -574,7 +581,7 @@ void io_save_cal(enum save_display display)
 		keys_wait_for_any_key(win[KEY].p);
 	}
 
-	pthread_mutex_unlock(&io_save_mutex);
+	io_mutex_unlock();
 	run_hook("post-save");
 }
 
@@ -865,8 +872,10 @@ void io_load_todo(struct item_filter *filter)
 void io_load_data(struct item_filter *filter)
 {
 	run_hook("pre-load");
+	io_mutex_lock();
 	io_load_app(filter);
 	io_load_todo(filter);
+	io_mutex_unlock();
 	run_hook("post-load");
 }
 
@@ -1495,10 +1504,10 @@ void io_stop_psave_thread(void)
 		return;
 
 	/* Lock the mutex to avoid cancelling the thread during saving. */
-	io_save_mutex_lock();
+	io_mutex_lock();
 	pthread_cancel(io_t_psave);
 	pthread_join(io_t_psave, NULL);
-	io_save_mutex_unlock();
+	io_mutex_unlock();
 }
 
 /*