Implement multibar UI

Multiplexed download requires ability to draw UI for multiple active progress
bars. To implement it we use ANSI codes to move cursor up/down and then
redraw the required progress bar.
`pacman_multibar_ui.active_downloads` field represents the list of active
downloads that correspond to progress bars.
`struct pacman_progress_bar` is a data structure for a progress bar.

In some cases (e.g. database downloads) we want to keep progress bars in order.
In some other cases (package downloads) we want to move completed items to the
top of the screen. Function `multibar_move_completed_up` allows to configure
such behavior.

Per discussion in the maillist we do not want to show download progress for
signature files.

Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>

8 files changed, 320 insertions, 159 deletions

diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
index add1a576..86015ab6 100644
--- a/lib/libalpm/be_sync.c
+++ b/lib/libalpm/be_sync.c
@@ -366,6 +366,7 @@ int SYMEXPORT alpm_dbs_update(alpm_handle_t *handle, alpm_list_t *dbs, int force
 		if(siglevel & ALPM_SIG_DATABASE) {
 			struct dload_payload *sig_payload;
 			CALLOC(sig_payload, 1, sizeof(*sig_payload), GOTO_ERR(handle, ALPM_ERR_MEMORY, cleanup));
+			sig_payload->signature = 1;
 
 			/* print filename into a buffer (leave space for separator and .sig) */
 			len = strlen(db->treename) + strlen(dbext) + 5;
diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index 2f360ab8..9ab0e5c4 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -90,6 +90,11 @@ static int dload_progress_cb(void *file, curl_off_t dltotal, curl_off_t dlnow,
 	off_t current_size, total_size;
 	alpm_download_event_progress_t cb_data = {0};
 
+	/* do not print signature files progress bar */
+	if(payload->signature) {
+		return 0;
+	}
+
 	/* avoid displaying progress bar for redirects with a body */
 	if(payload->respcode >= 300) {
 		return 0;
@@ -100,6 +105,11 @@ static int dload_progress_cb(void *file, curl_off_t dltotal, curl_off_t dlnow,
 		return 1;
 	}
 
+	if(dlnow < 0 || dltotal <= 0 || dlnow > dltotal) {
+		/* bogus values : stop here */
+		return 0;
+	}
+
 	current_size = payload->initial_size + dlnow;
 
 	/* is our filesize still under any set limit? */
@@ -115,34 +125,15 @@ static int dload_progress_cb(void *file, curl_off_t dltotal, curl_off_t dlnow,
 
 	total_size = payload->initial_size + dltotal;
 
-	if(dltotal == 0 || payload->prevprogress == total_size) {
+	if(payload->prevprogress == total_size) {
 		return 0;
 	}
 
-	/* initialize the progress bar here to avoid displaying it when
-	 * a repo is up to date and nothing gets downloaded.
-	 * payload->handle->dlcb will receive the remote_name
-	 * and the following arguments:
-	 * 0, -1: download initialized
-	 * 0, 0: non-download event
-	 * x {x>0}, x: download complete
-	 * x {x>0, x<y}, y {y > 0}: download progress, expected total is known */
-	if(!payload->cb_initialized) {
-		cb_data.downloaded = 0;
-		cb_data.total = -1;
-		payload->cb_initialized = 1;
-	}
-	if(payload->prevprogress == current_size) {
-		cb_data.downloaded = 0;
-		cb_data.total = 0;
-	} else {
 	/* do NOT include initial_size since it wasn't part of the package's
 	 * download_size (nor included in the total download size callback) */
-		cb_data.downloaded = dlnow;
-		cb_data.total = dltotal;
-	}
+	cb_data.total = dltotal;
+	cb_data.downloaded = dlnow;
 	payload->handle->dlcb(payload->remote_name, ALPM_DOWNLOAD_PROGRESS, &cb_data);
-
 	payload->prevprogress = current_size;
 
 	return 0;
@@ -375,6 +366,8 @@ static int curl_download_internal(struct dload_payload *payload,
 	double remote_size, bytes_dl;
 	struct sigaction orig_sig_pipe, orig_sig_int;
 	CURLcode curlerr;
+	alpm_download_event_init_t init_cb_data = {0};
+	alpm_download_event_completed_t completed_cb_data = {0};
 	/* shortcut to our handle within the payload */
 	alpm_handle_t *handle = payload->handle;
 	CURL *curl = curl_easy_init();
@@ -444,6 +437,8 @@ static int curl_download_internal(struct dload_payload *payload,
 	dload_interrupted = 0;
 	mask_signal(SIGINT, &inthandler, &orig_sig_int);
 
+	handle->dlcb(payload->remote_name, ALPM_DOWNLOAD_INIT, &init_cb_data);
+
 	/* perform transfer */
 	curlerr = curl_easy_perform(curl);
 	_alpm_log(handle, ALPM_LOG_DEBUG, "curl returned error %d from transfer\n",
@@ -604,6 +599,10 @@ cleanup:
 		raise(SIGINT);
 	}
 
+	completed_cb_data.total = bytes_dl;
+	completed_cb_data.result = ret;
+	handle->dlcb(payload->remote_name, ALPM_DOWNLOAD_COMPLETED, &completed_cb_data);
+
 	return ret;
 }
 
@@ -665,7 +664,6 @@ static int curl_multi_check_finished_download(CURLM *curlm, CURLMsg *msg,
 	long remote_time = -1;
 	struct stat st;
 	char hostname[HOSTNAME_SIZE];
-	alpm_download_event_completed_t cb_data = {0};
 	int ret = -1;
 
 	curlerr = curl_easy_getinfo(curl, CURLINFO_PRIVATE, &payload);
@@ -825,9 +823,12 @@ cleanup:
 		unlink(payload->tempfile_name);
 	}
 
-	cb_data.total = bytes_dl;
-	cb_data.result = ret;
-	handle->dlcb(payload->remote_name, ALPM_DOWNLOAD_COMPLETED, &cb_data);
+	if(!payload->signature) {
+		alpm_download_event_completed_t cb_data = {0};
+		cb_data.total = bytes_dl;
+		cb_data.result = ret;
+		handle->dlcb(payload->remote_name, ALPM_DOWNLOAD_COMPLETED, &cb_data);
+	}
 
 	curl_multi_remove_handle(curlm, curl);
 	curl_easy_cleanup(curl);
@@ -945,9 +946,11 @@ static int curl_multi_download_internal(alpm_handle_t *handle,
 			struct dload_payload *payload = payloads->data;
 
 			if(curl_multi_add_payload(handle, curlm, payload, localpath) == 0) {
-				alpm_download_event_init_t cb_data = {.optional = payload->errors_ok};
+				if(!payload->signature) {
+					alpm_download_event_init_t cb_data = {.optional = payload->errors_ok};
+					handle->dlcb(payload->remote_name, ALPM_DOWNLOAD_INIT, &cb_data);
+				}
 
-				handle->dlcb(payload->remote_name, ALPM_DOWNLOAD_INIT, &cb_data);
 				payloads = payloads->next;
 				// TODO: report that download has started
 			} else {
@@ -1129,6 +1132,7 @@ char SYMEXPORT *alpm_fetch_pkgurl(alpm_handle_t *handle, const char *url)
 
 		sig_filepath = filecache_find_url(handle, payload.fileurl);
 		if(sig_filepath == NULL) {
+			payload.signature = 1;
 			payload.handle = handle;
 			payload.trust_remote_name = 1;
 			payload.force = 1;
@@ -1184,5 +1188,4 @@ void _alpm_dload_payload_reset_for_retry(struct dload_payload *payload)
 	payload->initial_size += payload->prevprogress;
 	payload->prevprogress = 0;
 	payload->unlink_on_fail = 0;
-	payload->cb_initialized = 0;
 }
diff --git a/lib/libalpm/dload.h b/lib/libalpm/dload.h
index a40b51b7..1e4af755 100644
--- a/lib/libalpm/dload.h
+++ b/lib/libalpm/dload.h
@@ -42,7 +42,7 @@ struct dload_payload {
 	int errors_ok;
 	int unlink_on_fail;
 	int trust_remote_name;
-	int cb_initialized;
+	int signature; /* specifies if the payload is a signature file */
 #ifdef HAVE_LIBCURL
 	CURL *curl;
 	char error_buffer[CURL_ERROR_SIZE];
diff --git a/src/pacman/callback.c b/src/pacman/callback.c
index 613d59d4..c2e516ec 100644
--- a/src/pacman/callback.c
+++ b/src/pacman/callback.c
@@ -18,6 +18,8 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <assert.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -52,6 +54,50 @@ static alpm_list_t *output = NULL;
 #define CLOCK_MONOTONIC_COARSE CLOCK_MONOTONIC
 #endif
 
+struct pacman_progress_bar {
+	const char *filename;
+	off_t xfered;
+	off_t total_size;
+	uint64_t init_time; /* Time when this download started doing any progress */
+	uint64_t sync_time; /* Last time we updated the bar info */
+	double rate;
+	unsigned int eta; /* ETA in seconds */
+	bool completed; /* transfer is completed */
+};
+
+/* This datastruct represents the state of multiline progressbar UI */
+struct pacman_multibar_ui {
+	/* List of active downloads handled by multibar UI.
+	 * Once the first download in the list is completed it is removed
+	 * from this list and we never redraw it anymore.
+	 * If the download is in this list, then the UI can redraw the progress bar or change
+	 * the order of the bars (e.g. moving completed bars to the top of the list)
+	 */
+	alpm_list_t *active_downloads; /* List of type 'struct pacman_progress_bar' */
+
+	/* Number of active download bars that multibar UI handles. */
+	size_t active_downloads_num;
+
+	/* Specifies whether a completed progress bar need to be reordered and moved
+	 * to the top of the list.
+	 */
+	bool move_completed_up;
+
+	/* Cursor position relative to the first active progress bar,
+	 * e.g. 0 means the first active progress bar, active_downloads_num-1 means the last bar,
+	 * active_downloads_num - is the line below all progress bars.
+	 */
+	int cursor_lineno;
+};
+
+struct pacman_multibar_ui multibar_ui = {0};
+
+static void cursor_goto_end(void);
+
+void multibar_move_completed_up(bool value) {
+	multibar_ui.move_completed_up = value;
+}
+
 static int64_t get_time_ms(void)
 {
 #if defined(_POSIX_TIMERS) && (_POSIX_TIMERS > 0) && defined(CLOCK_MONOTONIC_COARSE)
@@ -152,11 +198,7 @@ static void fill_progress(const int bar_percent, const int disp_percent,
 		printf(" %3d%%", disp_percent);
 	}
 
-	if(bar_percent == 100) {
-		putchar('\n');
-	} else {
-		putchar('\r');
-	}
+	putchar('\r');
 	fflush(stdout);
 }
 
@@ -346,6 +388,7 @@ void cb_event(alpm_event_t *event)
 		case ALPM_EVENT_DB_RETRIEVE_FAILED:
 		case ALPM_EVENT_PKG_RETRIEVE_DONE:
 		case ALPM_EVENT_PKG_RETRIEVE_FAILED:
+			cursor_goto_end();
 			flush_output_list();
 			on_progress = 0;
 			break;
@@ -629,6 +672,7 @@ void cb_progress(alpm_progress_t event, const char *pkgname, int percent,
 	fill_progress(percent, percent, cols - infolen);
 
 	if(percent == 100) {
+		putchar('\n');
 		flush_output_list();
 		on_progress = 0;
 	} else {
@@ -647,149 +691,87 @@ void cb_dl_total(off_t total)
 	}
 }
 
-/* callback to handle display of download progress */
-static void dload_progress_event(const char *filename, off_t file_xfered, off_t file_total)
+static int dload_progressbar_enabled(void)
+{
+	return !config->noprogressbar && (getcols() != 0);
+}
+
+/* Goto the line that corresponds to num-th active download */
+static void cursor_goto_bar(int num)
+{
+	if(num > multibar_ui.cursor_lineno) {
+		console_cursor_move_down(num - multibar_ui.cursor_lineno);
+	} else if(num < multibar_ui.cursor_lineno) {
+		console_cursor_move_up(multibar_ui.cursor_lineno - num);
+	}
+	multibar_ui.cursor_lineno = num;
+}
+
+/* Goto the line *after* the last active progress bar */
+static void cursor_goto_end(void)
+{
+	cursor_goto_bar(multibar_ui.active_downloads_num);
+}
+
+/* Returns true if element with the specified name is found, false otherwise */
+static bool find_bar_for_filename(const char *filename, int *index, struct pacman_progress_bar **bar)
+{
+	int i = 0;
+	alpm_list_t *listitem = multibar_ui.active_downloads;
+	for(; listitem; listitem = listitem->next, i++) {
+		struct pacman_progress_bar *b = listitem->data;
+		if (strcmp(b->filename, filename) == 0) {
+			/* we found a progress bar with the given name */
+			*index = i;
+			*bar = b;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static void draw_pacman_progress_bar(struct pacman_progress_bar *bar)
 {
-	static double rate_last;
-	static off_t xfered_last;
-	static int64_t initial_time = 0;
 	int infolen;
 	int filenamelen;
 	char *fname, *p;
 	/* used for wide character width determination and printing */
 	int len, wclen, wcwid, padwid;
 	wchar_t *wcfname;
-
-	int totaldownload = 0;
-	off_t xfered, total;
-	double rate = 0.0;
-	unsigned int eta_h = 0, eta_m = 0, eta_s = 0;
+	unsigned int eta_h = 0, eta_m = 0, eta_s = bar->eta;
 	double rate_human, xfered_human;
 	const char *rate_label, *xfered_label;
-	int file_percent = 0, total_percent = 0;
+	int file_percent = 0;
 
 	const unsigned short cols = getcols();
 
-	/* Nothing has changed since last callback; stop here */
-	if(file_xfered == 0 && file_total == 0) {
-		return;
-	}
-
-	if(config->noprogressbar || cols == 0) {
-		if(file_xfered == 0 && file_total == -1) {
-			printf(_("downloading %s...\n"), filename);
-			fflush(stdout);
-		}
-		return;
-	}
-
-	infolen = cols * 6 / 10;
-	if(infolen < 50) {
-		infolen = 50;
-	}
-	/* only use TotalDownload if enabled and we have a callback value */
-	if(config->totaldownload && list_total) {
-		/* sanity check */
-		if(list_xfered + file_total <= list_total) {
-			totaldownload = 1;
-		} else {
-			/* bogus values : don't enable totaldownload and reset */
-			list_xfered = 0;
-			list_total = 0;
-		}
-	}
-
-	if(totaldownload) {
-		xfered = list_xfered + file_xfered;
-		total = list_total;
-	} else {
-		xfered = file_xfered;
-		total = file_total;
-	}
-
-	/* this is basically a switch on xfered: 0, total, and
-	 * anything else */
-	if(file_xfered == 0 && file_total == -1) {
-		/* set default starting values, ensure we only call this once
-		 * if TotalDownload is enabled */
-		if(!totaldownload || (totaldownload && list_xfered == 0)) {
-			initial_time = get_time_ms();
-			xfered_last = (off_t)0;
-			rate_last = 0.0;
-			get_update_timediff(1);
-		}
-	} else if(xfered > total || xfered < 0) {
-		/* bogus values : stop here */
-		return;
-	} else if(file_xfered == file_total) {
-		/* compute final values */
-		int64_t timediff = get_time_ms() - initial_time;
-		if(timediff > 0) {
-			rate = (double)xfered / (timediff / 1000.0);
-			/* round elapsed time (in ms) to the nearest second */
-			eta_s = (unsigned int)(timediff + 500) / 1000;
-		} else {
-			eta_s = 0;
-		}
-	} else {
-		/* compute current average values */
-		int64_t timediff = get_update_timediff(0);
-
-		if(timediff < UPDATE_SPEED_MS) {
-			/* return if the calling interval was too short */
-			return;
-		}
-		rate = (double)(xfered - xfered_last) / (timediff / 1000.0);
-		/* average rate to reduce jumpiness */
-		rate = (rate + 2 * rate_last) / 3;
-		if(rate > 0.0) {
-			eta_s = (total - xfered) / rate;
-		} else {
-			eta_s = UINT_MAX;
-		}
-		rate_last = rate;
-		xfered_last = xfered;
-	}
-
-	if(file_total) {
-		file_percent = (file_xfered * 100) / file_total;
+	if(bar->total_size) {
+		file_percent = (bar->xfered * 100) / bar->total_size;
 	} else {
 		file_percent = 100;
 	}
 
-	if(totaldownload) {
-		total_percent = ((list_xfered + file_xfered) * 100) /
-			list_total;
-
-		/* if we are at the end, add the completed file to list_xfered */
-		if(file_xfered == file_total) {
-			list_xfered += file_total;
-		}
-	}
-
 	/* fix up time for display */
 	eta_h = eta_s / 3600;
 	eta_s -= eta_h * 3600;
 	eta_m = eta_s / 60;
 	eta_s -= eta_m * 60;
 
-	len = strlen(filename);
+	len = strlen(bar->filename);
 	fname = malloc(len + 1);
-	memcpy(fname, filename, len + 1);
+	memcpy(fname, bar->filename, len + 1);
 	/* strip package or DB extension for cleaner look */
 	if((p = strstr(fname, ".pkg")) || (p = strstr(fname, ".db")) || (p = strstr(fname, ".files"))) {
-		/* tack on a .sig suffix for signatures */
-		if(memcmp(&filename[len - 4], ".sig", 4) == 0) {
-			memcpy(p, ".sig", 4);
-
-			/* adjust length for later calculations */
-			len = p - fname + 4;
-		} else {
-			len = p - fname;
-		}
+		len = p - fname;
 		fname[len] = '\0';
 	}
 
+	infolen = cols * 6 / 10;
+	if(infolen < 50) {
+		infolen = 50;
+	}
+
 	/* 1 space + filenamelen + 1 space + 6 for size + 1 space + 3 for label +
 	 * + 2 spaces + 4 for rate + 1 space + 3 for label + 2 for /s + 1 space +
 	 * 8 for eta, gives us the magic 33 */
@@ -824,8 +806,8 @@ static void dload_progress_event(const char *filename, off_t file_xfered, off_t
 
 	}
 
-	rate_human = humanize_size((off_t)rate, '\0', -1, &rate_label);
-	xfered_human = humanize_size(xfered, '\0', -1, &xfered_label);
+	rate_human = humanize_size((off_t)bar->rate, '\0', -1, &rate_label);
+	xfered_human = humanize_size(bar->xfered, '\0', -1, &xfered_label);
 
 	printf(" %ls%-*s ", wcfname, padwid, "");
 	/* We will show 1.62 MiB/s, 11.6 MiB/s, but 116 KiB/s and 1116 KiB/s */
@@ -850,19 +832,166 @@ static void dload_progress_event(const char *filename, off_t file_xfered, off_t
 	free(fname);
 	free(wcfname);
 
-	if(totaldownload) {
-		fill_progress(file_percent, total_percent, cols - infolen);
+	fill_progress(file_percent, file_percent, cols - infolen);
+	return;
+}
+
+static void dload_init_event(const char *filename, alpm_download_event_init_t *data)
+{
+	(void)data;
+
+	if(!dload_progressbar_enabled()) {
+		printf(_(" %s downloading...\n"), filename);
+		return;
+	}
+
+	struct pacman_progress_bar *bar = calloc(1, sizeof(struct pacman_progress_bar));
+	assert(bar);
+	bar->filename = filename;
+	bar->init_time = get_time_ms();
+	bar->rate = 0.0;
+	multibar_ui.active_downloads = alpm_list_add(multibar_ui.active_downloads, bar);
+
+	cursor_goto_end();
+	printf(_(" %s downloading...\n"), filename);
+	multibar_ui.cursor_lineno++;
+	multibar_ui.active_downloads_num++;
+}
+
+/* Draws download progress */
+static void dload_progress_event(const char *filename, alpm_download_event_progress_t *data)
+{
+	int index;
+	struct pacman_progress_bar *bar;
+	int64_t curr_time = get_time_ms();
+	double last_chunk_rate;
+	int64_t timediff;
+
+	if(!dload_progressbar_enabled()) {
+		return;
+	}
+
+	assert(find_bar_for_filename(filename, &index, &bar));
+
+	/* compute current average values */
+	timediff = curr_time - bar->sync_time;
+
+	if(timediff < UPDATE_SPEED_MS) {
+		/* return if the calling interval was too short */
+		return;
+	}
+	bar->sync_time = curr_time;
+
+	last_chunk_rate = (double)(data->downloaded - bar->xfered) / (timediff / 1000.0);
+	/* average rate to reduce jumpiness */
+	bar->rate = (last_chunk_rate + 2 * bar->rate) / 3;
+	if(bar->rate > 0.0) {
+		bar->eta = (data->total - data->downloaded) / bar->rate;
 	} else {
-		fill_progress(file_percent, file_percent, cols - infolen);
+		bar->eta = UINT_MAX;
+	}
+
+	/* Total size is received after the download starts. */
+	bar->total_size = data->total;
+	bar->xfered = data->downloaded;
+
+	cursor_goto_bar(index);
+	draw_pacman_progress_bar(bar);
+	fflush(stdout);
+}
+
+/* download completed */
+static void dload_complete_event(const char *filename, alpm_download_event_completed_t *data)
+{
+	int index;
+	struct pacman_progress_bar *bar;
+	int64_t timediff;
+
+	if(!dload_progressbar_enabled()) {
+		return;
+	}
+
+	assert(find_bar_for_filename(filename, &index, &bar));
+	bar->completed = true;
+
+	/* This may not have been initialized if the download finished before
+	 * an alpm_download_event_progress_t event happened */
+	bar->total_size = data->total;
+
+	if(data->result == 1) {
+		cursor_goto_bar(index);
+		printf(_(" %s is up to date"), bar->filename);
+		/* The line contains text from previous status. Erase these leftovers. */
+		console_erase_line();
+	} else if(data->result == 0) {
+		/* compute final values */
+		bar->xfered = bar->total_size;
+		timediff = get_time_ms() - bar->init_time;
+
+		/* if transfer was too fast, treat it as a 1ms transfer, for the sake
+		 * of the rate calculation */
+		if(timediff < 1)
+			timediff = 1;
+
+		bar->rate = (double)bar->xfered / (timediff / 1000.0);
+		/* round elapsed time (in ms) to the nearest second */
+		bar->eta = (unsigned int)(timediff + 500) / 1000;
+
+		if(multibar_ui.move_completed_up && index != 0) {
+			/* If this item completed then move it to the top.
+			 * Swap 0-th bar data with `index`-th one
+			 */
+			struct pacman_progress_bar *former_topbar = multibar_ui.active_downloads->data;
+			alpm_list_t *baritem = alpm_list_nth(multibar_ui.active_downloads, index);
+			multibar_ui.active_downloads->data = bar;
+			baritem->data = former_topbar;
+
+			cursor_goto_bar(index);
+			draw_pacman_progress_bar(former_topbar);
+
+			index = 0;
+		}
+
+		cursor_goto_bar(index);
+		draw_pacman_progress_bar(bar);
+	} else {
+		cursor_goto_bar(index);
+		printf(_(" %s failed to download"), bar->filename);
+		console_erase_line();
+	}
+	fflush(stdout);
+
+	/* If the first bar is completed then there is no reason to keep it
+	 * in the list as we are not going to redraw it anymore.
+	 */
+	while(multibar_ui.active_downloads) {
+		alpm_list_t *head = multibar_ui.active_downloads;
+		struct pacman_progress_bar *j = head->data;
+		if(j->completed) {
+			multibar_ui.cursor_lineno--;
+			multibar_ui.active_downloads_num--;
+			multibar_ui.active_downloads = alpm_list_remove_item(
+				multibar_ui.active_downloads, head);
+			free(head);
+			free(j);
+		} else {
+			break;
+		}
 	}
-	return;
 }
 
+/* Callback to handle display of download progress */
 void cb_download(const char *filename, alpm_download_event_type_t event, void *data)
 {
-	if(event == ALPM_DOWNLOAD_PROGRESS) {
-		alpm_download_event_progress_t *progress = data;
-		dload_progress_event(filename, progress->downloaded, progress->total);
+	if(event == ALPM_DOWNLOAD_INIT) {
+		dload_init_event(filename, data);
+	} else if(event == ALPM_DOWNLOAD_PROGRESS) {
+		dload_progress_event(filename, data);
+	} else if(event == ALPM_DOWNLOAD_COMPLETED) {
+		dload_complete_event(filename, data);
+	} else {
+		pm_printf(ALPM_LOG_ERROR, _("unknown callback event type %d for %s\n"),
+				event, filename);
 	}
 }
 
diff --git a/src/pacman/callback.h b/src/pacman/callback.h
index 6d92e86b..09d544a6 100644
--- a/src/pacman/callback.h
+++ b/src/pacman/callback.h
@@ -20,6 +20,7 @@
 #ifndef PM_CALLBACK_H
 #define PM_CALLBACK_H
 
+#include <stdbool.h>
 #include <sys/types.h> /* off_t */
 
 #include <alpm.h>
@@ -44,4 +45,7 @@ void cb_download(const char *filename, alpm_download_event_type_t event,
 __attribute__((format(printf, 2, 0)))
 void cb_log(alpm_loglevel_t level, const char *fmt, va_list args);
 
+/* specify if multibar UI should move completed bars to the top of the screen */
+void multibar_move_completed_up(bool value);
+
 #endif /* PM_CALLBACK_H */
diff --git a/src/pacman/sync.c b/src/pacman/sync.c
index f7dcb958..a05af5da 100644
--- a/src/pacman/sync.c
+++ b/src/pacman/sync.c
@@ -35,6 +35,7 @@
 #include "pacman.h"
 #include "util.h"
 #include "package.h"
+#include "callback.h"
 #include "conf.h"
 
 static int unlink_verbose(const char *pathname, int ignore_missing)
@@ -824,6 +825,7 @@ int sync_prepare_execute(void)
 		goto cleanup;
 	}
 
+	multibar_move_completed_up(true);
 	if(alpm_trans_commit(config->handle, &data) == -1) {
 		alpm_errno_t err = alpm_errno(config->handle);
 		pm_printf(ALPM_LOG_ERROR, _("failed to commit transaction (%s)\n"),
diff --git a/src/pacman/util.c b/src/pacman/util.c
index 97b8e06d..03035037 100644
--- a/src/pacman/util.c
+++ b/src/pacman/util.c
@@ -1837,3 +1837,21 @@ char *arg_to_string(int argc, char *argv[])
 	strcpy(p, argv[i]);
 	return cl_text;
 }
+
+/* Moves console cursor `lines` up */
+void console_cursor_move_up(unsigned int lines)
+{
+	printf("\x1B[%dF", lines);
+}
+
+/* Moves console cursor `lines` down */
+void console_cursor_move_down(unsigned int lines)
+{
+	printf("\x1B[%dE", lines);
+}
+
+/* Erases line from the current cursor position till the end of the line */
+void console_erase_line(void)
+{
+	printf("\x1B[K");
+}
diff --git a/src/pacman/util.h b/src/pacman/util.h
index 2b21f3d5..c97048fb 100644
--- a/src/pacman/util.h
+++ b/src/pacman/util.h
@@ -83,6 +83,10 @@ char *arg_to_string(int argc, char *argv[]);
 char *safe_fgets_stdin(char *s, int size);
 void console_cursor_hide(void);
 void console_cursor_show(void);
+void console_cursor_move_up(unsigned int lines);
+void console_cursor_move_down(unsigned int lines);
+/* Erases line from the current cursor position till the end of the line */
+void console_erase_line(void);
 
 int pm_printf(alpm_loglevel_t level, const char *format, ...) __attribute__((format(printf,2,3)));
 int pm_asprintf(char **string, const char *format, ...) __attribute__((format(printf,2,3)));