From 9a6f97cfe15ebd721868e1b2025224aa75ac4e48 Mon Sep 17 00:00:00 2001
From: uz <uz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Fri, 28 May 2010 11:56:01 +0000
Subject: [PATCH] PushSearchPath will add the path only if it's not already
 there.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4672 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 src/common/searchpath.c | 24 +++++++++++++++++++-----
 src/common/searchpath.h |  7 +++++--
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/common/searchpath.c b/src/common/searchpath.c
index a91383460..217502299 100644
--- a/src/common/searchpath.c
+++ b/src/common/searchpath.c
@@ -156,11 +156,25 @@ void AddSubSearchPathFromEnv (SearchPath* P, const char* EnvVar, const char* Sub
 
 
 
-void PushSearchPath (SearchPath* P, const char* NewPath)
-/* Add a new search path to the head of an existing search path list */
-{
-    /* Insert a clean copy of the path at position 0 */
-    CollInsert (P, CleanupPath (NewPath), 0);
+int PushSearchPath (SearchPath* P, const char* NewPath)
+/* Add a new search path to the head of an existing search path list, provided
+ * that it's not already there. If the path is already at the first position,
+ * return zero, otherwise return a non zero value.
+ */
+{                                      
+    /* Generate a clean copy of NewPath */
+    char* Path = CleanupPath (NewPath);   
+
+    /* If we have paths, check if Path is already at position zero */
+    if (CollCount (P) > 0 && strcmp (CollConstAt (P, 0), Path) == 0) {
+        /* Match. Delete the copy and return to the caller */
+        xfree (Path);
+        return 0;
+    }
+
+    /* Insert a clean copy of the path at position 0, return success */
+    CollInsert (P, Path, 0);
+    return 1;
 }
 
 
diff --git a/src/common/searchpath.h b/src/common/searchpath.h
index 6c4745e59..f9f870563 100644
--- a/src/common/searchpath.h
+++ b/src/common/searchpath.h
@@ -75,8 +75,11 @@ void AddSubSearchPathFromEnv (SearchPath* P, const char* EnvVar, const char* Sub
  * the environment variable value.
  */
 
-void PushSearchPath (SearchPath* P, const char* NewPath);
-/* Add a new search path to the head of an existing search path list */
+int PushSearchPath (SearchPath* P, const char* NewPath);
+/* Add a new search path to the head of an existing search path list, provided
+ * that it's not already there. If the path is already at the first position,
+ * return zero, otherwise return a non zero value.
+ */
 
 void PopSearchPath (SearchPath* P);
 /* Remove a search path from the head of an existing search path list */
-- 
2.39.5