history when getting line from user in knob

src/kernel/kbd.c

@@ -110,7 +110,7 @@ enum {
   CODE_NDOT,
   CODE_NSLASH,
   /* 0xc0 unassigned */
-  CODE_DELETE,
+  CODE_DELETE = 0xc1,
   CODE_HOME,
   CODE_END,
   CODE_PUP,

src/user/highway/line.c

@@ -57,25 +57,28 @@ void run_line(const char *original_line) {
   const char *space;
   for (space = line; *space && (*space != ' '); ++space)
     ;
-  if (blockequ(line, "source", space - line))
+  if (blockequ(line, "source ", 7))
     source(space + 1);
-  else if (blockequ(line, "set", space - line))
+  else if (blockequ(line, "set ", 4))
     set(space + 1);
-  else if (blockequ(line, "echo", space - line)) {
+  else if (blockequ(line, "echo ", 5)) {
     tell_user_sz(space + 1);
     tell_user_sz("\n");
   }
-  else if (blockequ(line, "vars", space - line))
+  else if (blockequ(line, "vars", 5))
     dump_vars();
-  else if (blockequ(line, "quit", space - line))
+  else if (blockequ(line, "quit", 5))
     __pcrt_quit();
-  else if (blockequ(line, "help", space - line))
+  else if (blockequ(line, "clear", 6))
+    _clear_screen();
+  else if (blockequ(line, "help", 5))
     tell_user_sz("Highway is a command shell for Portland OS. It includes variables and a couple\n"
                  "of pseudo-commands. Variables are addressed by surrounding with \"$\". The\n"
                  "following list shows each of the pseudo-commands.\n\n"
                  "  source FILE       run each command in FILE\n"
-                 "  set VAR VALUE     set $VAR$ to VALUE\n"
+                 "  clear             clear the screen\n"
                  "  echo STRING       print STRING\n"
+                 "  set VAR VALUE     set $VAR$ to VALUE\n"
                  "  vars              dump variables\n"
                  "  quit              exit highway\n"
                  "  help              show this\n");

src/user/highway/main.c

@@ -7,10 +7,11 @@ void main(const char *arg) {
   source(*arg ? arg : "user/default.rc");
   char cmd_buf[128];
   yield_task();
+  struct history *cmd_hs = new_history(128);
   tell_user_sz("Portland Highway\nType \"help\" for help.\n");
   while (1) {
     tell_user_sz("\n> ");
-    ask_user_line_sz(cmd_buf, 127);
+    ask_user_line_sz_with_history(cmd_buf, 127, cmd_hs);
     run_line(cmd_buf);
   }
 }

src/user/include/knob/block.h

@@ -10,4 +10,7 @@ bool blockequ(const void *a, const void *b, uint32_t size) __attribute__ ((__pur
 //returns length without null-terminator
 uint32_t strcpy(char *to, const char *from);
 
+//allocates new memory
+char *strdup(const char *from);
+
 #endif

src/user/include/knob/user.h

@@ -4,6 +4,8 @@
 #include <stdint.h>
 #include <pland/syscall.h>
 
+struct history;
+
 char key_to_char(_key_code_t key) __attribute__ ((const));
 
 void tell_user_sz(const char *sz);
@@ -12,4 +14,9 @@ void tell_user_sz(const char *sz);
 //returns the real length of the string
 uint32_t ask_user_line_sz(char *sz, uint32_t max_length);
 
+struct history *new_history(uint32_t max_entries);
+void del_history(struct history *hs);
+
+uint32_t ask_user_line_sz_with_history(char *sz, uint32_t max_length, struct history *hs);
+
 #endif

src/user/include/pland/syscall.h

@@ -73,7 +73,7 @@ typedef enum {
   _KEY_NDOT,
   _KEY_NSLASH,
   /* 0xc0 unassigned */
-  _KEY_DELETE,
+  _KEY_DELETE = 0xc1,
   _KEY_HOME,
   _KEY_END,
   _KEY_PUP,

src/user/knob/block.c

@@ -1,5 +1,6 @@
-#include <stdint.h>
 #include <stdbool.h>
+#include <stdint.h>
+#include <knob/heap.h>
 
 //unsophisticated, should copy by dwords where available
 void blockcpy(void *to, const void *from, uint32_t size) {
@@ -23,4 +24,13 @@ uint32_t strcpy(char *to, const char *from) {
     to[i] = from[i];
   while (from[i++]);
   return i - 1;
+}
+
+char *strdup(const char *from) {
+  const char *end = from;
+  while (*(end++))
+    ;
+  char *buf = get_block(end - from);
+  blockcpy(buf, from, end - from);
+  return buf;
 }

src/user/knob/user.c

@@ -1,4 +1,6 @@
 #include <pland/syscall.h>
+#include <knob/block.h>
+#include <knob/heap.h>
 #include <stdint.h>
 #include <stdbool.h>
 
@@ -170,5 +172,128 @@ uint32_t ask_user_line_sz(char *sz, uint32_t max_length) {
   }
 
   sz[i] = '\0';
+  return i;
+}
+
+struct history_entry {
+  struct history_entry *prev;
+  struct history_entry *next;
+  const char *contents;
+};
+
+struct history {
+  struct history_entry *earliest_history_item;
+  struct history_entry *latest_history_item;
+  uint32_t max_entries;
+  uint32_t cur_entries;
+};
+
+struct history *new_history(uint32_t max_entries) {
+  struct history *new = get_block(sizeof(struct history));
+  new->latest_history_item = 0;
+  new->earliest_history_item = 0;
+  new->max_entries = max_entries;
+  new->cur_entries = 0;
+  return new;
+}
+
+void del_history(struct history *hs) {
+  free_block(hs);
+  for (struct history_entry *he = hs->latest_history_item; he; he = he->prev) {
+    free_block(he);
+    free_block(he->contents);
+  }
+}
+
+//return value and max_length don't include null terminator
+uint32_t ask_user_line_sz_with_history(char *sz, uint32_t max_length, struct history *hs) {
+  char log_buf[2];
+  log_buf[1] = '\0';
+  struct history_entry *cur_he = 0;
+
+  uint32_t i;
+  for (i = 0; i != max_length; ++i) {
+    char key;
+  replace:
+    key = get_key_char();
+    if (!key)
+      goto replace;
+    if (key == (char)_KEY_UP) {
+      struct history_entry *new_cur_he = cur_he ? cur_he->prev : hs->latest_history_item;
+      if (new_cur_he) {
+        cur_he = new_cur_he;
+        for (uint32_t j = 0; j < i; ++j)
+          _log_string("\b");
+        i = strcpy(sz, cur_he->contents);
+        _log_string(sz);
+      }
+      goto replace;
+    }
+    if (key == (char)_KEY_DOWN) {
+      cur_he = cur_he ? cur_he->next : 0;
+      for (uint32_t j = 0; j < i; ++j)
+        _log_string("\b");
+      if (cur_he) {
+        i = strcpy(sz, cur_he->contents);
+        _log_string(sz);
+      }
+      else
+        i = 0;
+      goto replace;
+    }
+    if (key & 0x80)
+      goto replace;//TODO
+    if (key == '\b') {
+      if (i) {
+        --i;
+        _log_string("\b");
+      }
+      goto replace;
+    }
+
+    log_buf[0] = key;
+    _log_string(log_buf);
+
+    if (key == '\n')
+      break;
+    sz[i] = key;
+  }
+
+  sz[i] = '\0';
+
+  struct history_entry *new_he = get_block(sizeof(struct history_entry));
+  new_he->contents = strdup(sz);
+
+  new_he->next = 0;
+  if (hs->latest_history_item) {
+    new_he->prev = hs->latest_history_item;
+    hs->latest_history_item->next = new_he;
+  }
+  else
+    new_he->prev = 0;
+  hs->latest_history_item = new_he;
+  if (!hs->earliest_history_item)
+    hs->earliest_history_item = new_he;
+  if (hs->max_entries == hs->cur_entries) {
+    free_block(hs->earliest_history_item);
+    free_block(hs->earliest_history_item->contents);
+    hs->earliest_history_item->next->prev = 0;
+    hs->earliest_history_item = hs->earliest_history_item->next;
+  }
+  else
+    ++(hs->cur_entries);
+
+  for (struct history_entry *check_he = hs->latest_history_item->prev; check_he; check_he = check_he->prev) {
+    if (blockequ(check_he->contents, sz, i + 1)) {
+      check_he->next->prev = check_he->prev;
+      if (check_he->prev)
+        check_he->prev->next = check_he->next;
+      else
+        hs->earliest_history_item = check_he->next;
+      free_block(check_he);
+      free_block(check_he->contents);
+    }
+  }
+
   return i;
 }