From 69487ed29aed49ca0e3481e9783e02e9156258b2 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Fri, 22 May 2020 17:14:48 -0700
Subject: fix: encapsulated the IO stack into the lexer

---
 sys/cmd/cc/lex.c | 147 +++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 110 insertions(+), 37 deletions(-)

(limited to 'sys/cmd/cc/lex.c')

diff --git a/sys/cmd/cc/lex.c b/sys/cmd/cc/lex.c
index a8dabec..1eb269c 100644
--- a/sys/cmd/cc/lex.c
+++ b/sys/cmd/cc/lex.c
@@ -22,6 +22,115 @@ puttok(Token tok)
         printf("ident <%s>", tok.val.s);
 }
 
+// -----------------------------------------------------------------------
+// io buffer management
+
+#define asrdr(x) (io·Reader){(int (*)(void *, int, int, void *))x}
+
+// path should be absolute 
+Io*
+openio(Lexer *lx, byte *path)
+{
+    string *it, *end;
+    Stream *f;
+
+    intern(&path);
+
+    // See if we have already opened file;
+    // If so, and it hasn't been flagged return it
+    for (it = lx->omit.path, end = it + lx->omit.len; it < end; ++it) {
+        if ((uintptr)(*it) == (uintptr)(path))
+            return nil;
+    }
+
+    // TODO: See if we have already loaded the file
+    
+    if ((lx->new - lx->iostk) >= arrlen(lx->iostk)-1) 
+        panicf("out of I/O space!");
+
+    lx->new->f = io·open(path, "r");
+    if (!lx->new->f)
+        panicf("file %s not found", path);
+
+    lx->new->kind = IOfile;
+    lx->new->path = path;
+    bufio·initreader(&lx->new->rdr, asrdr(io·read), lx->new->f);
+
+    return lx->new++;
+} 
+
+static
+Io*
+makeio(Lexer *lx, byte *name)
+{
+    if ((lx->new - lx->iostk) >= arrlen(lx->iostk)-1) 
+        panicf("out of I/O space!");
+
+    lx->new->path = name;
+    lx->new->rdr = (io·Buffer) {
+        .state    = bufio·rdr | bufio·end, 
+        .runesize = 0,
+        .h        = nil,
+        .size     = bufio·size,
+        .beg      = lx->new->rdr.buf + bufio·ungets,
+        .pos      = lx->new->rdr.buf + bufio·ungets,
+        .end      = lx->new->rdr.buf + bufio·ungets,
+    };
+    lx->new->b = lx->new->rdr.beg;
+
+    return lx->new++;
+} 
+#undef asrdr
+
+static
+void
+freeio(Lexer *lx, Io *io)
+{
+    if (io->kind & IOfile) {
+        io·close(io->f);
+    }
+
+    io->rdr.state = 0;
+    io->kind      = 0;
+    io->link      = nil;
+    io->path      = nil;
+    io->store     = (Pos){ 0 };
+    io->path      = "<empty>";
+}
+
+void
+pushio(Lexer *lx, Io *new)
+{
+    new->link     = lx->io;
+    lx->io->store = lx->pos;
+    lx->io        = new;
+
+    lx->pos = (Pos){
+        .line = 1,
+        .col  = 1,
+        .path = new->path,
+    };
+}
+
+void
+popio(Lexer *lx)
+{
+    Io *prev;
+
+    assert(lx->io == lx->new-1);
+    --lx->new;
+
+    prev = lx->io->link;
+    freeio(lx, lx->io);
+
+    lx->io = prev;
+    if (!prev) {
+        return;
+    }
+
+    lx->pos = prev->store;
+}
+
 // -----------------------------------------------------------------------
 // simple wrappers
 
@@ -648,7 +757,7 @@ Dispatch:
                 tok.val.s = lx->pos.path;
                 goto Return;
             }
-            io = makeio(sym->name);
+            io = makeio(lx, sym->name);
             io->rdr.end   += expandmacro(lx, sym, io->b);
             *io->rdr.end++ = EOF;
             pushio(lx, io);
@@ -675,42 +784,6 @@ Nospace:
 #undef CASE2
 #undef CASE1
 
-// -----------------------------------------------------------------------
-// push/pop io objects
-
-void
-pushio(Lexer *lx, Io *new)
-{
-    new->link     = lx->io;
-    lx->io->store = lx->pos;
-    lx->io        = new;
-
-    lx->pos = (Pos){
-        .line = 1,
-        .col  = 1,
-        .path = new->path,
-    };
-}
-
-void
-popio(Lexer *lx)
-{
-    Io *prev;
-
-    assert(lx->io == C.io-1);
-    --C.io;
-
-    prev = lx->io->link;
-    freeio(lx->io);
-
-    lx->io = prev;
-    if (!prev) {
-        return;
-    }
-
-    lx->pos = prev->store;
-}
-
 // -----------------------------------------------------------------------
 // symbol tables
 
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