add stat for ASUs and send them #1582

NEWS.md

@@ -32,6 +32,7 @@ rearrangements of Notcurses.
     `ncpile_render_to_file()`. Rewrote `notcurses_render_to_buffer()` and
     `notcurses_render_to_file()` as trivial wrappers around these functions,
     and deprecated the latter. They will be removed in ABI3.
+  * Added support for application-synchronized updates, and a new stat.
 
 * 2.3.4 (2021-06-12)
   * Added the flag `NCVISUAL_OPTION_NOINTERPOLATE` to use non-interpolative

USAGE.md

@@ -3399,6 +3399,7 @@ typedef struct ncstats {
   uint64_t sprixelemissions; // sprixel draw count
   uint64_t sprixelelisions;  // sprixel elision count
   uint64_t sprixelbytes;     // sprixel bytes emitted
+  uint64_t appsync_updates;  // application-synchronized updates
 
   // current state -- these can decrease
   uint64_t fbbytes;          // total bytes devoted to all active framebuffers

doc/man/man3/notcurses_stats.3.md

@@ -41,6 +41,7 @@ typedef struct ncstats {
   uint64_t sprixelemissions; // sprixel draw count
   uint64_t sprixelelisions;  // sprixel elision count
   uint64_t sprixelbytes;     // sprixel bytes emitted
+  uint64_t appsync_updates;  // application-synchronized updates
 
   // current state -- these can decrease
   uint64_t fbbytes;          // bytes devoted to framebuffers

include/notcurses/notcurses.h

@@ -1393,6 +1393,7 @@ typedef struct ncstats {
   uint64_t defaultelisions;  // default color was emitted
   uint64_t defaultemissions; // default color was elided
   uint64_t refreshes;        // refresh requests (non-optimized redraw)
+  uint64_t appsync_updates;  // how many application-synchronized updates?
 
   // current state -- these can decrease
   uint64_t fbbytes;          // total bytes devoted to all active framebuffers

src/lib/input.c

@@ -819,7 +819,7 @@ stash_string(query_state* inits){
 // ought be fed to the machine, and -1 on an invalid state transition.
 static int
 pump_control_read(query_state* inits, unsigned char c){
-fprintf(stderr, "state: %2d char: %1c %3d %02x\n", inits->state, isprint(c) ? c : ' ', c, c);
+//fprintf(stderr, "state: %2d char: %1c %3d %02x\n", inits->state, isprint(c) ? c : ' ', c, c);
   if(c == NCKEY_ESC){
     inits->state = STATE_ESC;
     return 0;

src/lib/render.c

@@ -1096,8 +1096,12 @@ rasterize_core(notcurses* nc, const ncpile* p, FILE* out, unsigned phase){
   return 0;
 }
 
+// 'asu' on input is non-0 if application-synchronized updates are permitted
+// (they are not, for instance, when rendering to a non-tty). on output,
+// assuming success, it is non-0 if application-synchronized updates are
+// desired; in this case, an ASU footer is present at the end of the buffer.
 static int
-notcurses_rasterize_inner(notcurses* nc, ncpile* p, FILE* out){
+notcurses_rasterize_inner(notcurses* nc, ncpile* p, FILE* out, unsigned* asu){
   fseeko(out, 0, SEEK_SET);
   // we only need to emit a coordinate if it was damaged. the damagemap is a
   // bit per coordinate, one per struct crender.
@@ -1130,19 +1134,44 @@ notcurses_rasterize_inner(notcurses* nc, ncpile* p, FILE* out){
   if(fflush(out)){
     return -1;
   }
+#define MIN_ASU_SIZE 4096 // FIXME
+  if(*asu){
+    if(nc->rstate.mstrsize >= MIN_ASU_SIZE){
+      const char* endasu = get_escape(&nc->tcache, ESCAPE_ESU);
+      if(endasu){
+        if(fprintf(out, endasu) < 0 || fflush(out)){
+          return -1;
+        }
+      }else{
+        *asu = 0;
+      }
+    }else{
+      *asu = 0;
+    }
+  }
+#undef MIN_ASU_SIZE
   return nc->rstate.mstrsize;
 }
 
 // rasterize the rendered frame, and blockingly write it out to the terminal.
 static int
 raster_and_write(notcurses* nc, ncpile* p, FILE* out){
-  if(notcurses_rasterize_inner(nc, p, out) < 0){
+  // will we be using application-synchronized updates? if this comes back as
+  // non-zero, we are, and must emit the header. no ASU without a tty.
+  unsigned useasu = nc->ttyfd >= 0 ? true : false;
+  if(notcurses_rasterize_inner(nc, p, out, &useasu) < 0){
     return -1;
   }
   int ret = 0;
-  //fflush(nc->ttyfp);
   sigset_t oldmask;
   block_signals(&oldmask);
+  if(useasu){
+    const char* basu = get_escape(&nc->tcache, ESCAPE_BSU);
+    if(tty_emit(basu, nc->ttyfd)){
+      ret = -1;
+    }
+    ++nc->stats.appsync_updates;
+  }
   if(blocking_write(fileno(nc->ttyfp), nc->rstate.mstream, nc->rstate.mstrsize)){
     ret = -1;
   }
@@ -1384,7 +1413,8 @@ int ncpile_render_to_buffer(ncplane* p, char** buf, size_t* buflen){
     return -1;
   }
   notcurses* nc = ncplane_notcurses(p);
-  int bytes = notcurses_rasterize_inner(nc, ncplane_pile(p), nc->rstate.mstreamfp);
+  unsigned useacu = false; // no ACU to file
+  int bytes = notcurses_rasterize_inner(nc, ncplane_pile(p), nc->rstate.mstreamfp, &useacu);
   pthread_mutex_lock(&nc->statlock);
   update_render_bytes(&nc->stats, bytes);
   pthread_mutex_unlock(&nc->statlock);

src/lib/stats.c

@@ -144,6 +144,7 @@ void notcurses_stats_reset(notcurses* nc, ncstats* stats){
   stash->sprixelemissions += nc->stats.sprixelemissions;
   stash->sprixelelisions += nc->stats.sprixelelisions;
   stash->sprixelbytes += nc->stats.sprixelbytes;
+  stash->appsync_updates += nc->stats.appsync_updates;
 
   stash->fbbytes = nc->stats.fbbytes;
   stash->planes = nc->stats.planes;
@@ -214,10 +215,10 @@ void summarize_stats(notcurses* nc){
             (stats->bgelisions * 100.0) / (stats->bgemissions + stats->bgelisions));
     char totalbuf[BPREFIXSTRLEN + 1];
     qprefix(stats->sprixelbytes, 1, totalbuf, 1);
-    fprintf(stderr, "Sprixel emits:elides: %ju:%ju (%.2f%%) %sB\n",
+    fprintf(stderr, "Sprixel emits:elides: %ju:%ju (%.2f%%) %sB ASUs: %ju\n",
             stats->sprixelemissions, stats->sprixelelisions,
             (stats->sprixelemissions + stats->sprixelelisions) == 0 ? 0 :
             (stats->sprixelelisions * 100.0) / (stats->sprixelemissions + stats->sprixelelisions),
-            totalbuf);
+            totalbuf, stats->appsync_updates);
   }
 }