From 3cb475f26539cbb6a2edbef1d6285b39a409288c Mon Sep 17 00:00:00 2001
From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Mon, 25 Apr 2022 07:59:01 -0700
Subject: [PATCH] gvpr: replace use of alternative stack implementation with
 Graphviz generic one

Similar to previous changes to `gc` in 4e2875fd7376338259dcb3ccc8f029d58bdf22dd,
this replaces some duplicated functionality with the generic Graphviz stack
implementation. This also adds checks for allocation failures that were
previously missing.

Gitlab: #1793
---
 lib/gvpr/gvpr.c  | 10 +++++-----
 lib/gvpr/queue.h |  2 --
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/lib/gvpr/gvpr.c b/lib/gvpr/gvpr.c
index 1ae3e49e4..e43713196 100644
--- a/lib/gvpr/gvpr.c
+++ b/lib/gvpr/gvpr.c
@@ -21,6 +21,7 @@
 #include <cgraph/agxbuf.h>
 #include <cgraph/cgraph.h>
 #include <cgraph/exit.h>
+#include <cgraph/stack.h>
 #include <common/globals.h>
 #include <ingraphs/ingraphs.h>
 #include <gvpr/compile.h>
@@ -583,7 +584,7 @@ static void travBFS(Gpr_t * state, Expr_t* prog, comp_block * xprog)
 static void travDFS(Gpr_t * state, Expr_t* prog, comp_block * xprog, trav_fns * fns)
 {
     Agnode_t *n;
-    queue *stk;
+    gv_stack_t stk = {0};
     Agnode_t *curn;
     Agedge_t *cure;
     Agedge_t *entry;
@@ -592,7 +593,6 @@ static void travDFS(Gpr_t * state, Expr_t* prog, comp_block * xprog, trav_fns *
     nodestream nodes;
     Agedgepair_t seed;
 
-    stk = mkStack();
     nodes.oldroot = 0;
     nodes.prev = 0;
     while ((n = nextNode(state, &nodes))) {
@@ -630,7 +630,7 @@ static void travDFS(Gpr_t * state, Expr_t* prog, comp_block * xprog, trav_fns *
 			evalEdge(state, prog, xprog, cure);
 		} else {
 		    evalEdge(state, prog, xprog, cure);
-		    push(stk, entry);
+		    stack_push_or_exit(&stk, entry);
 		    state->tvedge = entry = cure;
 		    curn = cure->node;
 		    cure = 0;
@@ -645,7 +645,7 @@ static void travDFS(Gpr_t * state, Expr_t* prog, comp_block * xprog, trav_fns *
 		nd = nData(curn);
 		POP(nd);
 		cure = entry;
-		entry = (Agedge_t *) pull(stk);
+		entry = stack_is_empty(&stk) ? NULL : stack_pop(&stk);
 		if (entry == &(seed.out))
 		    state->tvedge = 0;
 		else
@@ -658,7 +658,7 @@ static void travDFS(Gpr_t * state, Expr_t* prog, comp_block * xprog, trav_fns *
 	}
     }
     state->tvedge = 0;
-    freeQ(stk);
+    stack_reset(&stk);
 }
 
 static void travNodes(Gpr_t * state, Expr_t* prog, comp_block * xprog)
diff --git a/lib/gvpr/queue.h b/lib/gvpr/queue.h
index 506aa1aee..bed779912 100644
--- a/lib/gvpr/queue.h
+++ b/lib/gvpr/queue.h
@@ -24,13 +24,11 @@ extern "C" {
     extern void freeQ(queue *);
 
 /* pseudo-functions:
-extern queue* mkStack();
 extern queue* mkQueue();
 extern void* pull(queue*);
 extern void* head(queue*);
  */
 
-#define mkStack()  mkQ(Dtstack)
 #define mkQueue()  mkQ(Dtqueue)
 #define pull(q)  (pop(q,1))
 #define head(q)  (pop(q,0))
-- 
2.40.0