interactive: Implement single key mode.

This changes the i9e subsystem to operate in single key mode while
a command is running as determined by the existence of a buffer tree
node which is attached to the stdout_btrn of i9e.

In single key mode a different readline key map is activated and
single keystrokes are passed to the application via the new key
handler function pointer of struct i9e_client_info.

diff --git a/interactive.c b/interactive.c
index 6831643878761be2da1c4ee8f79b7ce6ccf2f21f..a18d82b717846d1deeec01c3dcaf88587837bc43 100644 (file)
--- a/interactive.c
+++ b/interactive.c
@@ -35,6 +35,8 @@ struct i9e_private {
        bool input_eof;
        bool caught_sigint;
        bool caught_sigterm;
+       Keymap standard_km;
+       Keymap bare_km;
 };
 static struct i9e_private i9e_private, *i9ep = &i9e_private;
 
@@ -197,6 +199,7 @@ void i9e_attach_to_stdout(struct btr_node *producer)
        btr_remove_node(&i9ep->stdout_btrn);
        i9ep->stdout_btrn = btr_new_node(&(struct btr_node_description)
                EMBRACE(.name = "interactive_stdout", .parent = producer));
+       rl_set_keymap(i9ep->bare_km);
 }
 
 static void wipe_bottom_line(void)
@@ -223,6 +226,17 @@ static void wipe_bottom_line(void)
        fprintf(i9ep->stderr_stream, "\r");
 }
 
+/**
+ * Free all storage associated with a keymap.
+ *
+ * This function is not declared in the readline headers although the symbol is
+ * exported and the function is documented in the readline info file. So we
+ * have to declare it here.
+ *
+ * \param keymap The keymap to deallocate.
+ */
+void rl_free_keymap(Keymap keymap);
+
 /**
  * Reset the terminal and save the in-memory command line history.
  *
@@ -232,7 +246,8 @@ void i9e_close(void)
 {
        char *hf = i9ep->ici->history_file;
 
-       rl_deprep_terminal();
+       rl_free_keymap(i9ep->bare_km);
+       rl_callback_handler_remove();
        if (hf)
                write_history(hf);
        wipe_bottom_line();
@@ -291,17 +306,9 @@ static void i9e_line_handler(char *line)
        }
 }
 
-static void i9e_input(void)
-{
-       do {
-               rl_callback_read_char();
-       } while (input_available());
-}
-
-static void i9e_post_select(struct sched *s, struct task *t)
+static void i9e_post_select(__a_unused struct sched *s, struct task *t)
 {
        int ret;
-       struct btr_node *btrn = i9ep->stdout_btrn;
        struct i9e_client_info *ici = i9ep->ici;
        char *buf;
        size_t sz;
@@ -312,32 +319,40 @@ static void i9e_post_select(struct sched *s, struct task *t)
        ret = -E_I9E_TERM_RQ;
        if (i9ep->caught_sigterm)
                goto rm_btrn;
-       if (!btrn) {
-               i9ep->caught_sigint = false;
-               if (FD_ISSET(ici->fds[0], &s->rfds))
-                       i9e_input();
-               return;
-       }
        ret = 0;
        if (i9ep->caught_sigint)
                goto rm_btrn;
+       while (input_available())
+               rl_callback_read_char();
+       if (!i9ep->stdout_btrn)
+               goto out;
        ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
-       if (ret < 0)
+       if (ret < 0) {
+               ret = 0;
                goto rm_btrn;
-       sz = btr_next_buffer(btrn, &buf);
+       }
+       if (ret == 0)
+               goto out;
+       sz = btr_next_buffer(i9ep->stdout_btrn, &buf);
        if (sz == 0)
                goto out;
        ret = xwrite(ici->fds[1], buf, sz);
        if (ret < 0)
                goto rm_btrn;
-       btr_consume(btrn, ret);
+       btr_consume(i9ep->stdout_btrn, ret);
        goto out;
 rm_btrn:
-       btr_remove_node(&i9ep->stdout_btrn);
-       rl_set_prompt(i9ep->ici->prompt);
-       rl_redisplay();
+       if (i9ep->stdout_btrn) {
+               btr_remove_node(&i9ep->stdout_btrn);
+               rl_set_keymap(i9ep->standard_km);
+               rl_set_prompt(i9ep->ici->prompt);
+               rl_redisplay();
+       }
+       if (ret < 0)
+               wipe_bottom_line();
 out:
-       t->error = 0;
+       i9ep->caught_sigint = false;
+       t->error = ret;
 }
 
 static void i9e_pre_select(struct sched *s, __a_unused struct task *t)
@@ -384,6 +399,21 @@ static void update_winsize(void)
        i9ep->empty_line[i9ep->num_columns] = '\0';
 }
 
+/**
+ * Defined key sequences are mapped to keys starting with this offset. I.e.
+ * pressing the first defined key sequence yields the key number \p KEY_OFFSET.
+ */
+#define KEY_OFFSET 64
+
+static int dispatch_key(__a_unused int count, int key)
+{
+       int ret;
+
+       assert(key >= KEY_OFFSET);
+       ret = i9ep->ici->key_handler(key - KEY_OFFSET);
+       return ret < 0? ret : 0;
+}
+
 /**
  * Register the i9e task and initialize readline.
  *
@@ -418,12 +448,26 @@ int i9e_open(struct i9e_client_info *ici, struct sched *s)
        i9ep->stderr_stream = fdopen(ici->fds[2], "w");
        setvbuf(i9ep->stderr_stream, NULL, _IONBF, 0);
 
+       i9ep->standard_km = rl_get_keymap();
+       i9ep->bare_km = rl_make_bare_keymap();
+       if (ici->bound_keyseqs) {
+               char *seq;
+               int i;
+               /* FIXME: This is an arbitrary constant.  */
+               for (i = 0; i < 32 && (seq = ici->bound_keyseqs[i]); i++) {
+                       char buf[2] = {KEY_OFFSET + i, '\0'};
+                       /* readline needs an allocated buffer for the macro */
+                       rl_generic_bind(ISMACR, seq, para_strdup(buf), i9ep->bare_km);
+                       rl_bind_key_in_map(KEY_OFFSET + i, dispatch_key, i9ep->bare_km);
+               }
+       }
        if (ici->history_file)
                read_history(ici->history_file);
        update_winsize();
        if (ici->producer) {
                rl_callback_handler_install("", i9e_line_handler);
                i9e_attach_to_stdout(ici->producer);
+               rl_set_keymap(i9ep->bare_km);
        } else
                rl_callback_handler_install(i9ep->ici->prompt, i9e_line_handler);
        return 1;

diff --git a/interactive.h b/interactive.h
index 0af2ef40c27e38950654044ceb0770951ff328ef..fb39860541fef3c09c74b3bff9031c48e7b7a625 100644 (file)
--- a/interactive.h
+++ b/interactive.h
@@ -59,6 +59,10 @@ struct i9e_client_info {
        int loglevel;
        /** Complete input lines are passed to this callback function. */
        int (*line_handler)(char *line);
+       /** In single key mode, this callback is executed instead. */
+       int (*key_handler)(int key);
+       /** The array of valid key sequences for libreadline. */
+       char **bound_keyseqs;
        /** File descriptors to use for input/output/log. */
        int fds[3];
        /** Text of the current prompt. */