load smcap/rmcap and emit them

src/lib/notcurses.c

@@ -11,6 +11,9 @@
 
 typedef struct notcurses {
   int ttyfd;  // file descriptor for controlling tty (takes stdin)
+  int colors;
+  char* smcup;  // enter alternate mode
+  char* rmcup;  // restore primary mode
 } notcurses;
 
 static const char NOTCURSES_VERSION[] =
@@ -34,6 +37,30 @@ int notcurses_term_dimensions(notcurses* n, int* rows, int* cols){
   return 0;
 }
 
+static int
+term_get_seq(char** seq, const char* name){
+  *seq = tigetstr(name);
+  if(*seq == NULL || *seq == (char*)-1){
+    fprintf(stderr, "Capability not defined for terminal: %s\n", name);
+    return -1;
+  }
+  return 0;
+}
+
+static int
+term_emit(const char* seq){
+  int ret = printf("%s", seq);
+  if(ret < 0){
+    fprintf(stderr, "Error emitting %zub sequence (%s)\n", strlen(seq), strerror(errno));
+    return -1;
+  }
+  if((size_t)ret != strlen(seq)){
+    fprintf(stderr, "Short write (%db) for %zub sequence\n", ret, strlen(seq));
+    return -1;
+  }
+  return 0;
+}
+
 notcurses* notcurses_init(void){
   notcurses* ret = malloc(sizeof(*ret));
   if(ret == NULL){
@@ -45,19 +72,32 @@ notcurses* notcurses_init(void){
     free(ret);
     return NULL;
   }
+  if((ret->colors = tigetnum("colors")) <= 0){
+    fprintf(stderr, "This terminal doesn't appear to support colors\n");
+    free(ret);
+    return NULL;
+  }
+  printf("Colors: %d\n", ret->colors);
+  int fails = 0;
+  fails |= term_get_seq(&ret->smcup, "smcup");
+  fails |= term_get_seq(&ret->rmcup, "rmcup");
+  if(fails){
+    free(ret);
+    return NULL;
+  }
   // FIXME should we maybe use stdout if stdin was redirected?
   ret->ttyfd = STDIN_FILENO;
+  if(term_emit(ret->smcup)){
+    free(ret);
+    return NULL;
+  }
   return ret;
 }
 
 int notcurses_stop(notcurses* nc){
   int ret = 0;
   if(nc){
-    /*if(close(nc->ttyfd)){
-      fprintf(stderr, "Error closing TTY file descriptor %d (%s)\n",
-              nc->ttyfd, strerror(errno));
-      ret = -1;
-    }*/
+    ret |= term_emit(nc->rmcup);
     free(nc);
   }
   return ret;