avoid unnecessary cleanups of recovery files

* After the last commit 0b593eb7d0e6907b19cdbb605caf1becae351004
  we tried to clean up (unlink) recovery files for all dirty buffers.
  This resulted in superfluous file deletions before any recovery
  file was dumped; after disabling file recovery and even in
  batch mode.
  It's not tolerable that SciTECO scripts try to unlink files
  as a side effect e.g. of EW.
  Also, sometimes you may have to clean up recovery dumps even
  in batch mode, e.g. in Quit hooks.
* Also, it was broken for dirty unnamed buffers, which would
  cause glib errors.
* That's why we had to add another buffer state for
  dirty files with outdated recovery dumps (TECO_BUFFER_DIRTY_OUTDATED_DUMP).
  Once a dump was written, a buffer never directly transitions
  into the TECO_BUFFER_DIRTY_NO_DUMP state again.
  We can now reliably unlink() only where we'd expect a
  recovery file to exist in the first place.

2 files changed, 25 insertions, 18 deletions

diff --git a/src/ring.c b/src/ring.c
index 1fd39e9..fca32cc 100644
--- a/src/ring.c
+++ b/src/ring.c
@@ -118,11 +118,11 @@ teco_buffer_save(teco_buffer_t *ctx, const gchar *filename, GError **error)
 	 */
 	if (ctx == teco_ring_current && !teco_qreg_current)
 		undo__teco_interface_info_update_buffer(ctx);
-	if (ctx->state >= TECO_BUFFER_DIRTY) {
+	if (ctx->state > TECO_BUFFER_DIRTY_NO_DUMP) {
 		g_autofree gchar *filename_recovery = teco_buffer_get_recovery(ctx);
 		g_unlink(filename_recovery);
 		/* on rubout, we do not restore the recovery file */
-		ctx->state = TECO_BUFFER_DIRTY;
+		ctx->state = TECO_BUFFER_DIRTY_NO_DUMP;
 	}
 	teco_undo_guint(ctx->state) = TECO_BUFFER_CLEAN;
 
@@ -143,7 +143,7 @@ teco_buffer_save(teco_buffer_t *ctx, const gchar *filename, GError **error)
 static inline void
 teco_buffer_free(teco_buffer_t *ctx)
 {
-	if (ctx->state >= TECO_BUFFER_DIRTY) {
+	if (ctx->state > TECO_BUFFER_DIRTY_NO_DUMP) {
 		g_autofree gchar *filename_recovery = teco_buffer_get_recovery(ctx);
 		g_unlink(filename_recovery);
 	}
@@ -244,7 +244,7 @@ teco_ring_find_by_id(teco_int_t id)
 static void
 teco_ring_undirtify(void)
 {
-	if (teco_ring_current->state >= TECO_BUFFER_DIRTY) {
+	if (teco_ring_current->state > TECO_BUFFER_DIRTY_NO_DUMP) {
 		g_autofree gchar *filename_recovery = teco_buffer_get_recovery(teco_ring_current);
 		g_unlink(filename_recovery);
 	}
@@ -261,17 +261,18 @@ teco_ring_dirtify(void)
 	if (teco_qreg_current)
 		return;
 
-	teco_buffer_state_t old_state = teco_ring_current->state;
-	teco_ring_current->state = TECO_BUFFER_DIRTY;
-	switch (old_state) {
+	switch ((teco_buffer_state_t)teco_ring_current->state) {
 	case TECO_BUFFER_CLEAN:
+		teco_ring_current->state = TECO_BUFFER_DIRTY_NO_DUMP;
 		teco_interface_info_update(teco_ring_current);
 		undo__teco_ring_undirtify();
 		break;
-	case TECO_BUFFER_DIRTY:
+	case TECO_BUFFER_DIRTY_NO_DUMP:
+	case TECO_BUFFER_DIRTY_OUTDATED_DUMP:
 		break;
-	case TECO_BUFFER_DIRTY_DUMPED:
-		/* set to TECO_BUFFER_DIRTY on rubout */
+	case TECO_BUFFER_DIRTY_RECENT_DUMP:
+		teco_ring_current->state = TECO_BUFFER_DIRTY_OUTDATED_DUMP;
+		/* set to TECO_BUFFER_DIRTY_OUTDATED_DUMP on rubout */
 		teco_undo_guint(teco_ring_current->state);
 		break;
 	}
@@ -327,12 +328,16 @@ teco_ring_dump_recovery(void)
 
 	for (teco_tailq_entry_t *cur = teco_ring_head.first; cur != NULL; cur = cur->next) {
 		teco_buffer_t *buffer = (teco_buffer_t *)cur;
+		/* already dumped buffers don't have to be written again */
+		if (buffer->state != TECO_BUFFER_DIRTY_NO_DUMP &&
+		    buffer->state != TECO_BUFFER_DIRTY_OUTDATED_DUMP)
+			continue;
+
 		/*
 		 * Dirty unnamed buffers cannot be backed up.
-		 * Already backed-up buffers don't have to be written again.
-		 * FIXME: Perhaps they should be under ~/UNNAMED~?
+		 * FIXME: Perhaps they should be dumped under ~/#UNNAMED#?
 		 */
-		if (buffer->state != TECO_BUFFER_DIRTY || !buffer->filename)
+		if (!buffer->filename)
 			continue;
 
 		g_autofree gchar *filename_recovery = teco_buffer_get_recovery(buffer);
@@ -357,7 +362,7 @@ teco_ring_dump_recovery(void)
 		if (!teco_view_save_to_channel(buffer->view, channel, NULL))
 			continue;
 
-		buffer->state = TECO_BUFFER_DIRTY_DUMPED;
+		buffer->state = TECO_BUFFER_DIRTY_RECENT_DUMP;
 	}
 }
 
diff --git a/src/ring.h b/src/ring.h
index 4624983..d81c3db 100644
--- a/src/ring.h
+++ b/src/ring.h
@@ -28,10 +28,12 @@
 typedef enum {
 	/** buffer is freshly opened or saved */
 	TECO_BUFFER_CLEAN = 0,
-	/** buffer modified - if a recovery file already exists, it is outdated */
-	TECO_BUFFER_DIRTY,
-	/** buffer modified and recovery file already written */
-	TECO_BUFFER_DIRTY_DUMPED
+	/** buffer modified, but a recovery file does not yet exist */
+	TECO_BUFFER_DIRTY_NO_DUMP,
+	/** buffer modified, recovery file outdated */
+	TECO_BUFFER_DIRTY_OUTDATED_DUMP,
+	/** buffer modified and recovery file is up to date */
+	TECO_BUFFER_DIRTY_RECENT_DUMP
 } teco_buffer_state_t;
 
 typedef struct teco_buffer_t {