fixes for linux/libreadline compat

.vscode/tasks.json

@@ -4,11 +4,10 @@
  "type": "shell",
  "label": "make",
  "command": "/usr/bin/make",
- "args": ["PIPELINE_FLAGS=-g"],
  "options": {
  "cwd": "${workspaceFolder}"
  }
  }
  ],
  "version": "2.0.0"
-}
+}

src/main.c

@@ -1,11 +1,12 @@
+#include "config.h"
 #include <getopt.h>
 #include <ncurses.h>
 #include <readline/readline.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/wait.h>
 #include <term.h>
 #include <unistd.h>
-#include "config.h"
 
 #define PROGRAM_NAME "pipeline"
 char *program_name = PROGRAM_NAME;
@@ -18,6 +19,14 @@ int abort_ltz(int res) {
  return res;
 }
 
+int abort_nz(int res) {
+ if (res != 0) {
+ perror(NULL);
+ exit(res);
+ }
+ return res;
+}
+
 #define abort_null(ptr) \
  ({ \
  typeof(ptr) _ptr = ptr; \
@@ -44,7 +53,7 @@ void read_show_output(FILE *s, size_t *shown, size_t *total) {
  if (*shown < LINES - 2) {
  // sometimes newline, sometimes not, so chomp off any newline and
  // we'll add it ourselves for consistency.
- if (line[read-1] == '\n')
+ if (line[read - 1] == '\n')
  read -= 1;
  // truncate lines that are wider than the screen.
  if (read > COLS)
@@ -115,12 +124,26 @@ int show_preview(const char *a, int b) {
  for (int i = 0; i < (shown + 1); ++i) {
  termput("up");
  }
- rl_redisplay();
+ // moving the cursor left, necessary for libreadline but not libedit
+ printf("\e[9999D");
+ rl_forced_update_display();
  return 0;
 }
 
-int setup(const char *a, int b) {
- int res = rl_add_defun("pipeline-preview", show_preview, '\n');
+int setup() {
+ // libedit wants '\n' but libreadline wants '\r'.
+ //
+ // this ifdef is a hacky way to detect whether we're using readline or
+ // libedit, I'd love to find something cleaner.
+ //
+ // also note : rl_bind_key seems to be totally broken with libedit, at least
+ // on MacOS. I have to use rl_add_defun to see any effect in that
+ // environment.
+#ifdef RL_STATE_NONE
+ abort_nz(rl_add_defun("pipeline-preview", (rl_command_func_t *)show_preview, '\r'));
+#else
+ abort_nz(rl_add_defun("pipeline-preview", (Function *)show_preview, '\n'));
+#endif
  return 0;
 }