[pacman-dev] [PATCH] Implement multibar UI

Anatol Pomozov anatol.pomozov at gmail.com
Fri Apr 17 18:55:30 UTC 2020


Multiplexed download requires ability to draw UI for multiple active progress bars.
To implement it we use ANSI codes to move cursor up/down.
`active_dls` variable represents the list of active downloads.
`struct dl_progress_bar` is a data structure for an active progress bar.

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

Optional downloads (such as optional signature files) do not have a
visible progress bar.

Signed-off-by: Anatol Pomozov <anatol.pomozov at gmail.com>
---
 lib/libalpm/dload.c   |  31 +---
 lib/libalpm/dload.h   |   1 -
 src/pacman/callback.c | 401 +++++++++++++++++++++++++++++-------------
 src/pacman/callback.h |   3 +
 src/pacman/sync.c     |   2 +
 5 files changed, 294 insertions(+), 144 deletions(-)

diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index c09abde4..cf467ff0 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -100,6 +100,11 @@ 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 +120,15 @@ 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;
@@ -1160,5 +1146,4 @@ 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..142568e8 100644
--- a/lib/libalpm/dload.h
+++ b/lib/libalpm/dload.h
@@ -42,7 +42,6 @@ struct dload_payload {
 	int errors_ok;
 	int unlink_on_fail;
 	int trust_remote_name;
-	int cb_initialized;
 #ifdef HAVE_LIBCURL
 	CURL *curl;
 	char error_buffer[CURL_ERROR_SIZE];
diff --git a/src/pacman/callback.c b/src/pacman/callback.c
index 387319b6..a4aafada 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>
@@ -45,6 +47,8 @@ static off_t list_total = 0.0;
 static int on_progress = 0;
 static alpm_list_t *output = NULL;
 
+static void cursor_goto_end(void);
+
 /* update speed for the fill_progress based functions */
 #define UPDATE_SPEED_MS 200
 
@@ -152,11 +156,7 @@ 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 +346,7 @@ void cb_event(alpm_event_t *event)
 		case ALPM_EVENT_DB_RETRIEVE_FAILED:
 		case ALPM_EVENT_RETRIEVE_DONE:
 		case ALPM_EVENT_RETRIEVE_FAILED:
+			cursor_goto_end();
 			flush_output_list();
 			on_progress = 0;
 			break;
@@ -629,6 +630,7 @@ 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 {
@@ -647,124 +649,121 @@ 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)
 {
-	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;
+	return !config->noprogressbar && getcols() != 0;
+}
 
-	int totaldownload = 0;
-	off_t xfered, total;
-	double rate = 0.0;
-	unsigned int eta_h = 0, eta_m = 0, eta_s = 0;
-	double rate_human, xfered_human;
-	const char *rate_label, *xfered_label;
-	int file_percent = 0, total_percent = 0;
+struct dl_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 */
+	bool visible; /* whether to show the bar, some downloads (e.g. db.sig files) are not shown */
+};
 
-	const unsigned short cols = getcols();
+/* 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 in this list then UI can redraw the progress bar or change
+ * the order of the bars (e.g. completed bar is moved to the top of the list)
+ */
+alpm_list_t *active_dls = NULL;
+/* Number of active progress bars that multibar UI handles.
+ * Each progress bar has a corresponding active download.
+ * Note that some downloads might not have a bar, e.g. optional signature files
+ * do not have a corresponding bar.
+ */
+size_t active_bars_no = 0;
 
-	/* Nothing has changed since last callback; stop here */
-	if(file_xfered == 0 && file_total == 0) {
-		return;
-	}
+int multibar_move_complete_top = 0;
 
-	if(config->noprogressbar || cols == 0) {
-		if(file_xfered == 0 && file_total == -1) {
-			printf(_("downloading %s...\n"), filename);
-			fflush(stdout);
-		}
-		return;
-	}
+/* Cursor position relative to the first active progress bar,
+ * e.g. 0 means the first active progress bar, active_bars_no-1 means the last bar,
+ * active_bars_no - is the line below all progress bars.
+ */
+int cursor_lineno = 0;
 
-	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;
-		}
+/* Move console cursor `lines` up */
+static void cursor_line_up(unsigned int lines)
+{
+	assert(lines > 0);
+	printf("\x1B[%dF", lines);
+}
+
+/* Move console cursor `lines` down */
+static void cursor_line_down(unsigned int lines)
+{
+	assert(lines > 0);
+	printf("\x1B[%dE", lines);
+}
+
+/* Erase line from the cursor position till the end of the line */
+static void console_erase_line(void)
+{
+	printf("\x1B[K");
+}
+
+/* Goto the line that corresponds to num-th active download */
+static void cursor_goto_bar(int num)
+{
+	if(num > cursor_lineno) {
+		cursor_line_down(num - cursor_lineno);
+	} else if(num < cursor_lineno) {
+		cursor_line_up(cursor_lineno - num);
 	}
+	cursor_lineno = num;
+}
 
-	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);
+/* Goto the line *after* the last active progress bar */
+static void cursor_goto_end(void)
+{
+	cursor_goto_bar(active_bars_no);
+}
 
-		if(timediff < UPDATE_SPEED_MS) {
-			/* return if the calling interval was too short */
-			return;
+/* Returns true if element with the specified name is found, false otherwise */
+static bool find_bar_for_filename(const char *filename, int *index, struct dl_progress_bar **bar)
+{
+	int i = 0;
+	alpm_list_t *listitem = active_dls;
+	for(; listitem; listitem = listitem->next) {
+		struct dl_progress_bar *b = listitem->data;
+		if (b->filename == filename /* or strcmp() ? */) {
+			*index = i;
+			*bar = b;
+			return true;
 		}
-		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;
+		if(b->visible) {
+			i++;
 		}
-		rate_last = rate;
-		xfered_last = xfered;
 	}
 
-	if(file_total) {
-		file_percent = (file_xfered * 100) / file_total;
-	} else {
-		file_percent = 100;
-	}
+	return false;
+}
+
+static void draw_dl_progress_bar(struct dl_progress_bar *bar)
+{
+	int infolen;
+	int filenamelen;
+	char *fname, *p;
+	/* used for wide character width determination and printing */
+	int len, wclen, wcwid, padwid;
+	wchar_t *wcfname;
+	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;
 
-	if(totaldownload) {
-		total_percent = ((list_xfered + file_xfered) * 100) /
-			list_total;
+	const unsigned short cols = getcols();
 
-		/* if we are at the end, add the completed file to list_xfered */
-		if(file_xfered == file_total) {
-			list_xfered += file_total;
-		}
+	if(bar->total_size) {
+		file_percent = (bar->xfered * 100) / bar->total_size;
+	} else {
+		file_percent = 100;
 	}
 
 	/* fix up time for display */
@@ -773,13 +772,13 @@ static void dload_progress_event(const char *filename, off_t file_xfered, off_t
 	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) {
+		if(memcmp(&bar->filename[len - 4], ".sig", 4) == 0) {
 			memcpy(p, ".sig", 4);
 
 			/* adjust length for later calculations */
@@ -790,6 +789,11 @@ static void dload_progress_event(const char *filename, off_t file_xfered, off_t
 		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 +828,8 @@ 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 +854,176 @@ 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 dl_progress_bar *bar = calloc(1, sizeof(struct dl_progress_bar));
+	if(!bar) {
+		return;
+	}
+	bar->filename = filename;
+	bar->init_time = get_time_ms();
+	bar->rate = 0.0;
+	bar->visible = !data->optional;
+	active_dls = alpm_list_add(active_dls, bar);
+
+	if(bar->visible) {
+		cursor_goto_end();
+		printf(_(" %s downloading...\n"), filename);
+		cursor_lineno++;
+		active_bars_no++;
+	}
+}
+
+/* render download progress */
+static void dload_progress_event(const char *filename, alpm_download_event_progress_t *data)
+{
+	int index;
+	struct dl_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;
+
+	if(bar->visible) {
+		cursor_goto_bar(index);
+		draw_dl_progress_bar(bar);
+		fflush(stdout);
 	}
-	return;
 }
 
+/* download completed */
+static void dload_complete_event(const char *filename, alpm_download_event_completed_t *data)
+{
+	int index;
+	struct dl_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(bar->visible) {
+		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_move_complete_top && index != 0) {
+				/* If this item completed then move it to the top.
+				 * Swap 0-th bar data with `index`-th one
+				 */
+				struct dl_progress_bar *former_topbar = active_dls->data;
+				alpm_list_t *baritem = alpm_list_nth(active_dls, index);
+				active_dls->data = bar;
+				baritem->data = former_topbar;
+
+				cursor_goto_bar(index);
+				draw_dl_progress_bar(former_topbar);
+
+				index = 0;
+			}
+
+			cursor_goto_bar(index);
+			draw_dl_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(active_dls) {
+		alpm_list_t *head = active_dls;
+		struct dl_progress_bar *j = head->data;
+		if(j->completed) {
+			if(j->visible) {
+				cursor_lineno--;
+				active_bars_no--;
+			}
+			active_dls = alpm_list_remove_item(active_dls, head);
+			free(head);
+			free(j);
+		} else {
+			break;
+		}
+	}
+}
+
+/* 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..916b9dad 100644
--- a/src/pacman/callback.h
+++ b/src/pacman/callback.h
@@ -44,4 +44,7 @@ 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 should move complete bars to the top of the screen */
+int multibar_move_complete_top;
+
 #endif /* PM_CALLBACK_H */
diff --git a/src/pacman/sync.c b/src/pacman/sync.c
index f7dcb958..d5886f13 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_complete_top = 1;
 	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"),
-- 
2.26.1


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