shell: added completion support

src/builtins.c

@@ -1,8 +1,26 @@
 #include "builtins.h"
 
-const char* s_builtin_names[] = {"cd", "exit"};
+const char* s_builtin_names[] = {"cd", "exit", NULL};
 s_builtin s_builtins[] = {&s_cd, &s_exit};
 
+char* s_names(const char* text, int state) {
+  static int li, len;
+  const char* name;
+
+  if(!state) {
+    li = 0;
+    len = strlen(text);
+  }
+
+  while ((name = s_builtin_names[li++])) {
+      if (strncmp(name, text, len) == 0) {
+          return strdup(name);
+      }
+  }
+
+  return NULL;
+}
+
 int s_cd(char** args) {
   if (!args[1]) {
     s_error("cd", "expected argument");
@@ -17,5 +35,5 @@ int s_exit(char** args) {
 }
 
 int s_builtins_count() {
-  return sizeof(s_builtin_names) / sizeof(const char *);
+  return (sizeof(s_builtin_names) / sizeof(const char *)) - 1;
 }

src/builtins.h

@@ -1,9 +1,12 @@
+#include <string.h>
 #include <unistd.h>
 
 #include "util.h"
 
 typedef int (*s_builtin)(char**);
 
+char* s_names(const char* text, int state);
+
 int s_cd(char**);
 int s_exit(char**);
 int s_builtins_count();

src/shell.c

@@ -1,5 +1,10 @@
 #include "shell.h"
 
+char** s_completion(const char* text, int start, int end) {
+  rl_attempted_completion_over = 1;
+  return rl_completion_matches(text, s_names);
+}
+
 void s_die(const char* msg) {
   fprintf(stderr, "s: %s\n", msg);
   exit(1);
@@ -72,6 +77,8 @@ int s_exec(char** args) {
 }
 
 void s_loop() {
+  rl_attempted_completion_function = s_completion;
+
   char** cmd;
   int s;