Rearrange context saving.

Variables are now associated with the module that declares them, being
initialised and saved/restored there.  However, as many variables are
used for communication between modules, many of them are set in multiple
places, so the assignment is ambiguous.

1 files changed, 116 insertions, 0 deletions

diff --git a/Src/context.c b/Src/context.c
new file mode 100644
index 000000000..bd8d191bf
--- /dev/null
+++ b/Src/context.c
@@ -0,0 +1,116 @@
+/*
+ * context.c - context save and restore
+ *
+ * This file is part of zsh, the Z shell.
+ *
+ * Copyright (c) 1992-1997 Paul Falstad
+ * All rights reserved.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and to distribute modified versions of this software for any
+ * purpose, provided that the above copyright notice and the following
+ * two paragraphs appear in all copies of this software.
+ *
+ * In no event shall Paul Falstad or the Zsh Development Group be liable
+ * to any party for direct, indirect, special, incidental, or consequential
+ * damages arising out of the use of this software and its documentation,
+ * even if Paul Falstad and the Zsh Development Group have been advised of
+ * the possibility of such damage.
+ *
+ * Paul Falstad and the Zsh Development Group specifically disclaim any
+ * warranties, including, but not limited to, the implied warranties of
+ * merchantability and fitness for a particular purpose.  The software
+ * provided hereunder is on an "as is" basis, and Paul Falstad and the
+ * Zsh Development Group have no obligation to provide maintenance,
+ * support, updates, enhancements, or modifications.
+ *
+ */
+/*
+ * This short file provides a home for the stack of saved contexts.
+ * The actions for saving and restoring are encapsulated within
+ * individual modules.
+ */
+
+#include "zsh.mdh"
+#include "context.pro"
+
+struct context_stack {
+    struct context_stack *next;
+
+    struct hist_stack hist_stack;
+    struct lex_stack lex_stack;
+    struct parse_stack parse_stack;
+};
+
+static struct context_stack *cstack;
+
+/* save some or all of current context */
+
+/**/
+mod_export void
+zcontext_save_partial(int parts)
+{
+    struct context_stack *cs;
+
+    cs = (struct context_stack *)malloc(sizeof(struct context_stack));
+
+    if (parts & ZCONTEXT_HIST) {
+	hist_context_save(&cs->hist_stack, !cstack);
+    }
+    if (parts & ZCONTEXT_LEX) {
+	lex_context_save(&cs->lex_stack, !cstack);
+    }
+    if (parts & ZCONTEXT_PARSE) {
+	parse_context_save(&cs->parse_stack, !cstack);
+    }
+
+    cs->next = cstack;
+    cstack = cs;
+}
+
+/* save context in full */
+
+/**/
+mod_export void
+zcontext_save(void)
+{
+    zcontext_save_partial(ZCONTEXT_HIST|ZCONTEXT_LEX|ZCONTEXT_PARSE);
+}
+
+/* restore context or part thereof */
+
+/**/
+mod_export void
+zcontext_restore_partial(int parts)
+{
+    struct context_stack *cs = cstack;
+
+    DPUTS(!cstack, "BUG: zcontext_restore() without zcontext_save()");
+
+    queue_signals();
+    cstack = cstack->next;
+
+    if (parts & ZCONTEXT_HIST) {
+	hist_context_restore(&cs->hist_stack, !cstack);
+    }
+    if (parts & ZCONTEXT_LEX) {
+	lex_context_restore(&cs->lex_stack, !cstack);
+    }
+    if (parts & ZCONTEXT_PARSE) {
+	parse_context_restore(&cs->parse_stack, !cstack);
+    }
+
+    free(cs);
+
+    unqueue_signals();
+}
+
+/* restore full context */
+
+/**/
+mod_export void
+zcontext_restore(void)
+{
+    zcontext_restore_partial(ZCONTEXT_HIST|ZCONTEXT_LEX|ZCONTEXT_PARSE);
+}