From 68fc1605e7d3a317477abf1afc6410581724b72d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bert=20M=C3=BCnnich?= <ber.t@posteo.de>
Date: Sat, 5 Dec 2015 17:34:49 +0100
Subject: Completion of command names and variables

New completion entry functions for readline specific code:
  - compl_var for variables
  - compl_fn for functions
  - compl_builtin for builtins
  - compl_extcmd for external commands in path
  - compl_command, which combines the last three

The first three are simple wrappers for compl_name, which iterates over a
typical rc table (an array of structs) yielding the name fields.

The appropriate completion entry function is chosen based on the
character/token that preceeds the word to complete: '$' for variable,
beginning of line or one of [`@|&(){;] for command. Otherwise the shell falls
back to readline's default completion, which it also does, if the chosen
completion entry function finds no match.
---
 edit-readline.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

(limited to 'edit-readline.c')

diff --git a/edit-readline.c b/edit-readline.c
index acf96aa..9737e3e 100644
--- a/edit-readline.c
+++ b/edit-readline.c
@@ -2,6 +2,8 @@
 
 #include <errno.h>
 #include <stdio.h>
+#include <dirent.h>
+#include <sys/types.h>
 #include <readline/readline.h>
 #include <readline/history.h>
 #include <readline/rltypedefs.h>
@@ -14,11 +16,99 @@ struct cookie {
 	char *buffer;
 };
 
+static char *compl_extcmd(const char *text, int state) {
+	static DIR *d;
+	static List *path;
+	static size_t len;
+	char *name = NULL;
+
+	if (!state) {
+		d = NULL;
+		path = varlookup("path");
+		len = strlen(text);
+	}
+nextdir:
+	while (d == NULL) {
+		if (path == NULL)
+			return NULL;
+		d = opendir(path->w);
+		path = path->n;
+	}
+	while (name == NULL) {
+		struct dirent *e = readdir(d);
+		if (e == NULL) {
+			closedir(d);
+			d = NULL;
+			goto nextdir;
+		}
+		if (strncmp(e->d_name, text, len) == 0)
+			name = strdup(e->d_name);
+	}
+	return name;
+}
+
+static rl_compentry_func_t *const compl_cmd_funcs[] = {
+	compl_builtin,
+	compl_fn,
+	compl_extcmd
+};
+
+static char *compl_command(const char *text, int state) {
+	static size_t i;
+	static int s;
+	char *name = NULL;
+
+	if (!state) {
+		i = 0;
+		s = 0;
+	}
+	while (name == NULL && i < arraysize(compl_cmd_funcs)) {
+		name = compl_cmd_funcs[i](text, s);
+		if (name != NULL) {
+			s = 1;
+		} else {
+			i++;
+			s = 0;
+		}
+	}
+	return name;
+}
+
+static rl_compentry_func_t *compl_func(const char *text, int start, int end) {
+	int quote = FALSE;
+	char last = ';', *s, *t;
+
+	for (s = &rl_line_buffer[0], t = &rl_line_buffer[start]; s < t; s++) {
+		if (!quote && *s != ' ' && *s != '\t')
+			last = *s;
+		if (*s == '\'')
+			quote = !quote;
+	}
+	switch (last) {
+		case '`': case '@': case '|': case '&':
+		case '(': case ')': case '{': case ';':
+			return compl_command;
+		case '$':
+			return compl_var;
+	}
+	return NULL;
+}
+
+static char **rc_completion(const char *text, int start, int end) {
+	rl_compentry_func_t *func = compl_func(text, start, end);
+
+	if (func != NULL)
+		return rl_completion_matches(text, func);
+	else
+		return NULL;
+}
+
 void *edit_begin(int fd) {
 	List *hist;
 	struct cookie *c;
 
 	rl_initialize();
+	rl_attempted_completion_function = rc_completion;
 	rl_catch_signals = 0;
 	rl_completer_quote_characters = "'";
 	rl_filename_quote_characters = "\t\n !#$&'()*;<=>?@[\\]^`{|}~";
-- 
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