From 43688fe7190d0350349d47727c3663421d5618dc Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Mon, 8 Nov 2021 08:46:56 -0800
Subject: feat(rc): added back functionality of prompt, now unicode aware

---
 sys/cmd/rc/input.c  | 155 +++++++++++++++++++++++++++++++++++++++++++++-------
 sys/cmd/rc/main.c   |   1 +
 sys/cmd/rc/prompt.c |   7 ++-
 sys/cmd/rc/rc.h     |   7 ++-
 4 files changed, 148 insertions(+), 22 deletions(-)

diff --git a/sys/cmd/rc/input.c b/sys/cmd/rc/input.c
index 7ec8100..cc2383d 100644
--- a/sys/cmd/rc/input.c
+++ b/sys/cmd/rc/input.c
@@ -32,7 +32,8 @@ static int ascii[256] =
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 };
 
-struct Mode {
+struct Mode
+{
     ushort raw       : 1;
     ushort multiline : 1;
     ushort mask      : 1;
@@ -43,9 +44,6 @@ struct Mode {
     } vi ;
 };
 
-static struct Mode mode;
-static struct termios originalterm;
-
 /*
  * the structure represents the state during line editing.
  * we pass this state to functions implementing specific editing functionalities
@@ -82,8 +80,22 @@ struct TerminalState
     } yank;             /* yank buffer */
 
     intptr maxrows;     /* maximum num of rows used so far (multiline mode) */
+    intptr history;     /* index of history we are currently editing */
 };
 
+/*
+ * line history (circular buffer)
+ */
+struct History
+{
+    char **bot, **top, *entry[1024];
+};
+
+/* globals */
+static struct Mode    mode;
+static struct History history;
+static struct termios originalterm;
+
 enum
 {
     KeyNil       = 0,           /* nil */
@@ -293,14 +305,120 @@ beep(void)
     fflush(stderr);
 }
 
-/* =========================== Line editing ================================= */
+// -----------------------------------------------------------------------
+// command history
+
+void
+inithistory(void)
+{
+    history.bot = history.top = history.entry;
+}
+
+int
+addhistory(char *line)
+{
+    char *copy;
+
+    copy = strdup(line);
+    if(!copy)
+        return 0;
+
+    *history.top++ = copy;
+    if(history.top == arrend(history.entry))
+        history.top = history.entry;
+
+    if(history.top == history.bot){
+        efree(history.bot);
+        history.bot++;
+    }
+
+    return 1;
+}
+
+static
+void
+pophistory(void)
+{
+    if(--history.top < history.entry)
+        history.top = arrend(history.entry)-1;
+    efree(*history.top);
+}
+
+static void refreshline(struct TerminalState *);
 
-/* We define a very simple "append buffer" structure, that is an heap
- * allocated string where we can append to. This is useful in order to
+static
+char **
+currenthistory(struct TerminalState *term, intptr *size)
+{
+    char **entry;
+    intptr len, head;
+
+    if(history.top > history.bot){
+        len   = history.top - history.bot;
+        entry = history.top - term->history - 1;
+    }else if(history.top < history.bot){
+        len = (arrend(history.entry) - history.bot) + (history.top - history.entry);
+        if((head=history.top - history.entry) < term->history)
+            entry = arrend(history.entry) - head;
+        else
+            entry = history.top - term->history - 1;
+    }else
+        return nil;
+
+    *size = len;
+    return entry;
+}
+
+static
+void
+usehistory(struct TerminalState *term, int d)
+{
+    rune r;
+    intptr w, len;
+    char *b, *e, **entry;
+
+    if(!(entry = currenthistory(term, &len)))
+        return;
+
+    efree(*entry);
+    *entry = strdup(term->edit.buf);
+
+    term->history += d;
+    if(term->history < 0){
+        term->history = 0;
+        return;
+    }else if(term->history >= len){
+        term->history = len - 1;
+        return;
+    }
+    entry = currenthistory(term, &len);
+
+    strncpy(term->edit.buf, *entry, term->edit.cap);
+    term->edit.buf[term->edit.cap-1] = 0;
+
+    /* update cursor/buffer positions */
+    term->edit.len = term->edit.pos = strlen(term->edit.buf);
+    for(w=0, b=term->edit.buf, e=term->edit.buf+term->edit.len; b < e; ){
+        b += utf8·decode(b, &r);
+        w += utf8·runewidth(r);
+    }
+    term->cursor.len = term->cursor.pos = w;
+
+    refreshline(term);
+}
+
+// -----------------------------------------------------------------------
+// line editing
+
+/*
+ * we define a very simple "append buffer" structure, that is an heap
+ * allocated string where we can append to. this is useful in order to
  * write all the escape sequences in a buffer and flush them to the standard
- * output in a single call, to avoid flickering effects. */
+ * output in a single call, to avoid flickering effects.
+ */
 
-struct Buffer {
+struct Buffer
+{
     int len;
     char *b;
 };
@@ -667,14 +785,8 @@ refresh:
     term->cursor.len -= diff;
     refreshline(term);
 }
-
 /* movements */
 
-void
-movehistory(struct TerminalState *term, int dir)
-{
-}
-
 #define CURRENT(term) (Position){ .buffer=(term)->edit.pos, .cursor=(term)->cursor.pos };
 
 // move cursor to the left n boxes
@@ -1223,6 +1335,7 @@ interact(int ifd, int ofd, char *buf, intptr len, char *prompt)
     term.cursor.cap    = columns(ifd, ofd);
 
     term.maxrows       = 0;
+    term.history       = 0;
 
     term.yank.buf = nil;
     term.yank.cap = term.yank.len = 0;
@@ -1231,6 +1344,9 @@ interact(int ifd, int ofd, char *buf, intptr len, char *prompt)
     term.edit.buf[0] = '\0';
     term.edit.cap--; /* make sure there is always space for the nulterm */
 
+    /* push current (empty) command onto history stack */
+    addhistory("");
+
     if(write(term.ofd,prompt,term.prompt.len) == -1)
         return -1;
 
@@ -1259,6 +1375,7 @@ interact(int ifd, int ofd, char *buf, intptr len, char *prompt)
 
         switch(r){
         case KeyEnter:
+            pophistory();
             if(mode.multiline)
                 move(&term, END(term));
             goto finish;
@@ -1300,11 +1417,11 @@ interact(int ifd, int ofd, char *buf, intptr len, char *prompt)
             break;
 
         case KeyCtrlP:    /* ctrl-p */
-            /* TODO next history */
+            usehistory(&term, +1);
             break;
 
         case KeyCtrlN:    /* ctrl-n */
-            /* TODO prev history */
+            usehistory(&term, -1);
             break;
 
         case KeyEsc:    /* escape sequence */
@@ -1358,10 +1475,10 @@ interact(int ifd, int ofd, char *buf, intptr len, char *prompt)
                 }else{
                     switch(esc[1]) {
                     case 'A': /* up */
-                        movehistory(&term, 1);
+                        usehistory(&term, +1);
                         break;
                     case 'B': /* down */
-                        movehistory(&term, 0);
+                        usehistory(&term, -1);
                         break;
                     case 'C': /* right */
                         move(&term, right(&term, 1));
diff --git a/sys/cmd/rc/main.c b/sys/cmd/rc/main.c
index 865bcde..2c0aa42 100644
--- a/sys/cmd/rc/main.c
+++ b/sys/cmd/rc/main.c
@@ -58,6 +58,7 @@ main(int argc, char *argv[])
     initpath();
     initkeywords();
     initshell();
+    inithistory();
 
     enablevi();
     xboot(argc, argv);
diff --git a/sys/cmd/rc/prompt.c b/sys/cmd/rc/prompt.c
index ebda9fb..1122d54 100644
--- a/sys/cmd/rc/prompt.c
+++ b/sys/cmd/rc/prompt.c
@@ -19,8 +19,13 @@ prompt(ushort *flag)
             runner->flag.eof = 1;
             return 0;
         }
-        write(mapfd(0), "\n\r", 2);
+        if(runner->cmd.io->e[-1] == '\n'){
+            runner->cmd.io->e[-1] = 0;
+            addhistory(runner->cmd.io->b);
+            runner->cmd.io->e[-1] = '\n';
+        }
 
+        write(mapfd(0), "\n\r", 2);
         promptstr = "    ";
 
         runner->line++;
diff --git a/sys/cmd/rc/rc.h b/sys/cmd/rc/rc.h
index 32fb639..83c39e9 100644
--- a/sys/cmd/rc/rc.h
+++ b/sys/cmd/rc/rc.h
@@ -172,10 +172,13 @@ void *emalloc(uintptr);
 void *erealloc(void*, uintptr);
 void  efree(void*);
 
-/* read.c */
+/* input.c */
 int  readline(char *);
 void enablevi(void);
 
+void inithistory(void);
+int  addhistory(char *);
+
 /* prompt.c */
 void resetprompt(void);
 int  prompt(ushort *);
@@ -237,7 +240,7 @@ void background(Thread *, int);
 
 /* exec.c */
 // XXX: odd place for this
-int   count(Word *); 
+int   count(Word *);
 Word  *makeword(char *str, Word *link);
 void   freeword(Word *w);
 
-- 
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