Handling up/down arrow keys for history

include/key_functions.h

@@ -38,3 +38,6 @@ int forward_char_command(int key, buffer_t *buffer, env_t *env);
 int backward_char_command(int key, buffer_t *buffer, env_t *env);
 int beginning_of_line_command(int key, buffer_t *buffer, env_t *env);
 int end_of_line_command(int key, buffer_t *buffer, env_t *env);
+
+int up_history_command(int key, buffer_t *buffer, env_t *env);
+int down_history_command(int key, buffer_t *buffer, env_t *env);

include/shell.h

@@ -31,6 +31,8 @@ typedef struct buffer
     int size;
     int pos;
     int startx;
+    int history_index;
+    char *saved_buffer;
 } buffer_t;
 
 typedef struct alias_s

src/key_bindings/basic_typing_functions.c

@@ -69,6 +69,7 @@ int newline_command(int key, buffer_t *buffer, env_t *env)
         my_nresume(env->window);
         buffer->buffer[0] = '\0';
         buffer->pos = 0;
+        buffer->history_index = 0;
         if (env->window)
             my_getcuryx(&env->window->y, &env->window->x);
     }

src/key_bindings/control_commands.c

@@ -6,8 +6,54 @@
 */
 
 #include "shell.h"
+#include <stddef.h>
+#include <string.h>
+#include <malloc.h>
 
 int eof_command(int key, buffer_t *buffer, env_t *env)
 {
     return (-1);
+}
+
+bool set_buffer_to_history(buffer_t *buffer, env_t *env)
+{
+    history_t *hist = env->history;
+    char *cmd = NULL;
+    int len;
+
+    if (buffer->history_index == 0)
+        cmd = buffer->saved_buffer != NULL ? buffer->saved_buffer : "";
+    else
+        for (int i = 1; i < buffer->history_index && hist; i++)
+            hist = hist->next;
+    if (!cmd && (!hist || !(cmd = hist->command)))
+        return (false);
+    if (!buffer->buffer || buffer->size < (len = strlen(cmd))) {
+        buffer->buffer = realloc(buffer->buffer, buffer->size + len);
+        buffer->size += len;
+    }
+    if (!buffer->buffer)
+        return (false);
+    strcpy(buffer->buffer, cmd);
+    buffer->pos = strlen(buffer->buffer);
+    return (true);
+}
+
+int up_history_command(int key, buffer_t *buffer, env_t *env)
+{
+    if (buffer->buffer && buffer->history_index == 0)
+        buffer->saved_buffer = strdup(buffer->buffer);
+    buffer->history_index++;
+    if (!set_buffer_to_history(buffer, env))
+        buffer->history_index--;
+    return (0);
+}
+
+int down_history_command(int key, buffer_t *buffer, env_t *env)
+{
+    if (buffer->history_index <= 0)
+        return (0);
+    buffer->history_index--;
+    set_buffer_to_history(buffer, env);
+    return (0);
 }

src/key_bindings/default_bindings.c

@@ -33,5 +33,7 @@ const binding_t emacs_bindings[] = {
     {KEY_RIGHT, &forward_char_command},
     {KEY_HOME, &beginning_of_line_command},
     {KEY_END, &end_of_line_command},
+    {KEY_UP, &up_history_command},
+    {KEY_DOWN, &down_history_command},
     {0, NULL}
 };

src/shell.c

@@ -66,7 +66,7 @@ void shell_refresh(buffer_t *buffer, env_t *env)
 
 void start_shell(env_t *env)
 {
-    buffer_t buffer = {.size = 0, .buffer = NULL, .pos = 0, .startx = 0};
+    buffer_t buffer = {NULL, 0, 0, 0, 0, NULL};
     int key;
 
     if (isatty(0)) {
@@ -80,5 +80,9 @@ void start_shell(env_t *env)
         } else
             key = fgetc(stdin);
     } while (key != -1 && process_key(key, &buffer, env) >= 0);
+    if (buffer.saved_buffer)
+        free(buffer.saved_buffer);
+    if (buffer.buffer)
+        free(buffer.buffer);
     my_endwin(env->window);
 }