Decode input escape sequences to special keys #78

Add the necessary input buffer, non-blocking reads, escape trie,
and unit tests to support extended keys, including arrow keys.
Update notcurses-input to print Unicode Control Glyphs instead of
a blank space for control chars.

include/notcurses.h

@@ -154,7 +154,11 @@ typedef enum {
   NCKEY_RIGHT,
   NCKEY_DOWN,
   NCKEY_LEFT,
-  NCKEY_DC,       // delete
+  NCKEY_DEL,
+  NCKEY_PGDOWN,
+  NCKEY_PGUP,
+  NCKEY_HOME,
+  NCKEY_END,
   // FIXME...
 } ncspecial_key;
 
@@ -180,6 +184,11 @@ notcurses_getc_blocking(struct notcurses* n, cell* c, ncspecial_key* nkey){
   return notcurses_getc(n, c, nkey, NULL, &sigmask);
 }
 
+// Add this escape sequence to the trie, resolving to the specified specialkey.
+// Exported mainly for the benefit of unit tests.
+API int notcurses_add_input_escape(struct notcurses* nc, const char* esc,
+                                   ncspecial_key special);
+
 // Refresh our idea of the terminal's dimensions, reshaping the standard plane
 // if necessary. Without a call to this function following a terminal resize
 // (as signaled via SIGWINCH), notcurses_render() might not function properly.

src/demo/panelreel.c

@@ -315,7 +315,7 @@ panelreel_demo_core(struct notcurses* nc, int efd, tabletctx** tctxs){
           case NCKEY_RIGHT: ++x; if(panelreel_move(pr, x, y)){ --x; } break;
           case NCKEY_UP: panelreel_prev(pr); break;
           case NCKEY_DOWN: panelreel_next(pr); break;
-          case NCKEY_DC: kill_active_tablet(pr, tctxs); break;
+          case NCKEY_DEL: kill_active_tablet(pr, tctxs); break;
           default:
                     ncplane_cursor_move_yx(w, 3, 2);
                     ncplane_printf(w, "Unknown special (%d)\n", special);

src/lib/input.c

@@ -48,21 +48,24 @@ void input_free_esctrie(esctrie** eptr){
   }
 }
 
-int input_add_escape(notcurses* nc, const char* esc, ncspecial_key special){
-  esctrie** cur;
-  fprintf(stderr, "ADDING: %s for %d\n", esc, special);
+int notcurses_add_input_escape(notcurses* nc, const char* esc, ncspecial_key special){
   if(esc[0] != ESC || strlen(esc) < 2){ // assume ESC prefix + content
     return -1;
   }
+  esctrie** cur = &nc->inputescapes;
   do{
+//fprintf(stderr, "ADDING: %s (%zu) for %d\n", esc, strlen(esc), special);
     ++esc;
     int validate = *esc;
     if(validate < 0 || validate >= 0x80){
       return -1;
     }
-    if(nc->inputescapes == NULL){
-      cur = &nc->inputescapes;
-    }else if(validate){
+    if(*cur == NULL){
+      if((*cur = create_esctrie_node(NCKEY_INVALID)) == NULL){
+        return -1;
+      }
+    }
+    if(validate){
       if((*cur)->trie == NULL){
         const size_t tsize = sizeof((*cur)->trie) * 0x80;
         (*cur)->trie = malloc(tsize);
@@ -70,11 +73,6 @@ int input_add_escape(notcurses* nc, const char* esc, ncspecial_key special){
       }
       cur = &(*cur)->trie[validate];
     }
-    if(*cur == NULL){
-      if((*cur = create_esctrie_node(NCKEY_INVALID)) == NULL){
-        return -1;
-      }
-    }
   }while(*esc);
   if((*cur)->special){ // already had one here!
     return -1;
@@ -94,13 +92,24 @@ handle_getc(notcurses* nc, cell* c, int kpress, ncspecial_key* special){
   }
   if(kpress == ESC){
     // FIXME delay a little waiting for more?
-    while(nc->inputbuf_occupied){
+    const esctrie* esc = nc->inputescapes;
+    while(esc && esc->special == NCKEY_INVALID && nc->inputbuf_occupied){
       int candidate = pop_input_keypress(nc);
-      // FIXME walk trie via candidate, exiting (and ungetc()ing) on failure
-fprintf(stderr, "CANDIDATE: %c\n", candidate);
+//fprintf(stderr, "CANDIDATE: %c\n", candidate);
+      if(esc->trie == NULL){
+        esc = NULL;
+      }else if(candidate >= 0x80 || candidate < 0){
+        esc = NULL;
+      }else{
+        esc = esc->trie[candidate];
+      }
+    }
+    if(esc && esc->special != NCKEY_INVALID){
+      *special = esc->special;
+      return 1;
     }
+    // FIXME ungetc on failure! walk trie backwards or something
   }
-  *special = 0;
   if(kpress == 0x04){ // ctrl-d, treated as EOF
     return -1;
   }
@@ -137,10 +146,11 @@ static int
 handle_input(notcurses* nc, cell* c, ncspecial_key* special){
   int r;
   c->gcluster = 0;
+  *special = NCKEY_INVALID;
   // getc() returns unsigned chars cast to ints
   while(!input_queue_full(nc) && (r = getc(nc->ttyinfp)) >= 0){
     nc->inputbuf[nc->inputbuf_write_at] = (unsigned char)r;
-fprintf(stderr, "OCCUPY: %u@%u read: %d\n", nc->inputbuf_occupied, nc->inputbuf_write_at, nc->inputbuf[nc->inputbuf_write_at]);
+//fprintf(stderr, "OCCUPY: %u@%u read: %d\n", nc->inputbuf_occupied, nc->inputbuf_write_at, nc->inputbuf[nc->inputbuf_write_at]);
     if(++nc->inputbuf_write_at == sizeof(nc->inputbuf) / sizeof(*nc->inputbuf)){
       nc->inputbuf_write_at = 0;
     }

src/lib/internal.h

@@ -104,6 +104,8 @@ typedef struct notcurses {
   char* right; // kcuf1
   char* up;    // kcuu1
   char* down;  // kcud1
+  char* del;   // delete
+  char* home;  // home
   char* npage; // knp
   char* ppage; // kpp
 
@@ -127,9 +129,6 @@ typedef struct notcurses {
 
 extern sig_atomic_t resize_seen;
 
-// add this escape sequence to the trie, resolving to the specified specialkey
-int input_add_escape(notcurses* nc, const char* esc, ncspecial_key special);
-
 // free up the input escapes trie
 void input_free_esctrie(struct esctrie** trie);
 

src/lib/notcurses.c

@@ -520,12 +520,33 @@ interrogate_terminfo(notcurses* nc, const notcurses_options* opts){
   term_verify_seq(&nc->italoff, "ritm");
   term_verify_seq(&nc->op, "op");
   term_verify_seq(&nc->clear, "clear");
-  term_verify_seq(&nc->left, "kcub1");
-  term_verify_seq(&nc->right, "kcuf1");
-  term_verify_seq(&nc->up, "kcuu1");
-  term_verify_seq(&nc->down, "kcud1");
-  term_verify_seq(&nc->npage, "knp");
-  term_verify_seq(&nc->ppage, "kpp");
+  if(term_verify_seq(&nc->left, "kcub1") == 0){
+    notcurses_add_input_escape(nc, nc->left, NCKEY_LEFT);
+  }
+  if(term_verify_seq(&nc->right, "kcuf1") == 0){
+    notcurses_add_input_escape(nc, nc->right, NCKEY_RIGHT);
+  }
+  if(term_verify_seq(&nc->up, "kcuu1") == 0){
+    notcurses_add_input_escape(nc, nc->up, NCKEY_UP);
+  }
+  if(term_verify_seq(&nc->down, "kcud1") == 0){
+    notcurses_add_input_escape(nc, nc->down, NCKEY_DOWN);
+  }
+  if(term_verify_seq(&nc->del, "kdch1") == 0){
+    notcurses_add_input_escape(nc, nc->down, NCKEY_DEL);
+  }
+  if(term_verify_seq(&nc->home, "kend") == 0){
+    notcurses_add_input_escape(nc, nc->down, NCKEY_END);
+  }
+  if(term_verify_seq(&nc->home, "khome") == 0){
+    notcurses_add_input_escape(nc, nc->down, NCKEY_HOME);
+  }
+  if(term_verify_seq(&nc->npage, "knp") == 0){
+    notcurses_add_input_escape(nc, nc->down, NCKEY_PGDOWN);
+  }
+  if(term_verify_seq(&nc->ppage, "kpp") == 0){
+    notcurses_add_input_escape(nc, nc->down, NCKEY_PGUP);
+  }
   // Some terminals cannot combine certain styles with colors. Don't advertise
   // support for the style in that case.
   int nocolor_stylemask = tigetnum("ncv");

tests/notcurses.cpp

@@ -1,6 +1,7 @@
 #include <string>
 #include <cstdlib>
 #include <notcurses.h>
+#include "internal.h"
 #include "main.h"
 
 class NotcursesTest : public :: testing::Test {
@@ -103,3 +104,10 @@ TEST_F(NotcursesTest, TileScreenWithPlanes) {
   delete[] planes;
   ASSERT_EQ(0, notcurses_render(nc_));
 }
+
+// build a trie up from terminfo(5)-style escape sequences
+TEST_F(NotcursesTest, InputEscapesTrie) {
+  const char* khome = "\x1bOH";
+  ASSERT_EQ(0, notcurses_add_input_escape(nc_, khome, NCKEY_HOME));
+  // FIXME need be able to lookup
+}