From 3089c833ffa548d8965414d461bef023855dc34f Mon Sep 17 00:00:00 2001
From: Dan McGee <dan@archlinux.org>
Date: Wed, 30 Mar 2011 20:20:16 -0500
Subject: [PATCH] Unify filelist operation functions in conflict checking

We had two functions that were oh so similar but slightly different. We
can combine them and add some conditional operation stuff to decide what
to return.

Signed-off-by: Dan McGee <dan@archlinux.org>
---
 lib/libalpm/conflict.c | 76 ++++++++++++++----------------------------
 1 file changed, 25 insertions(+), 51 deletions(-)

diff --git a/lib/libalpm/conflict.c b/lib/libalpm/conflict.c
index b4ecd659..319e49d6 100644
--- a/lib/libalpm/conflict.c
+++ b/lib/libalpm/conflict.c
@@ -212,11 +212,17 @@ alpm_list_t SYMEXPORT *alpm_checkconflicts(alpm_list_t *pkglist) {
 	return _alpm_innerconflicts(pkglist);
 }
 
-/* Returns a alpm_list_t* of file conflicts.
- *  Hooray for set-intersects!
- *  Pre-condition: both lists are sorted!
+static const int DIFFERENCE = 0;
+static const int INTERSECT = 1;
+/* Returns a set operation on the provided two lists of files.
+ * Pre-condition: both lists are sorted!
+ *
+ * Operations:
+ *   DIFFERENCE - a difference operation is performed. filesA - filesB.
+ *   INTERSECT - an intersection operation is performed. filesA & filesB.
  */
-static alpm_list_t *chk_fileconflicts(alpm_list_t *filesA, alpm_list_t *filesB)
+static alpm_list_t *filelist_operation(alpm_list_t *filesA, alpm_list_t *filesB,
+		int operation)
 {
 	alpm_list_t *ret = NULL;
 	alpm_list_t *pA = filesA, *pB = filesB;
@@ -224,7 +230,7 @@ static alpm_list_t *chk_fileconflicts(alpm_list_t *filesA, alpm_list_t *filesB)
 	while(pA && pB) {
 		const char *strA = pA->data;
 		const char *strB = pB->data;
-		/* skip directories, we don't care about dir conflicts */
+		/* skip directories, we don't care about them */
 		if(strA[strlen(strA)-1] == '/') {
 			pA = pA->next;
 		} else if(strB[strlen(strB)-1] == '/') {
@@ -232,59 +238,26 @@ static alpm_list_t *chk_fileconflicts(alpm_list_t *filesA, alpm_list_t *filesB)
 		} else {
 			int cmp = strcmp(strA, strB);
 			if(cmp < 0) {
-				/* item only in filesA, ignore it */
+				if(operation == DIFFERENCE) {
+					/* item only in filesA, qualifies as a difference */
+					ret = alpm_list_add(ret, strdup(strA));
+				}
 				pA = pA->next;
 			} else if(cmp > 0) {
-				/* item only in filesB, ignore it */
 				pB = pB->next;
 			} else {
-				/* item in both, record it */
-				ret = alpm_list_add(ret, strdup(strA));
+				if(operation == INTERSECT) {
+					/* item in both, qualifies as an intersect */
+					ret = alpm_list_add(ret, strdup(strA));
+				}
 				pA = pA->next;
 				pB = pB->next;
 			}
 	  }
 	}
 
-	return ret;
-}
-
-/* Returns a alpm_list_t* of files that are in filesA but *NOT* in filesB
- *  This is an 'A minus B' set operation
- *  Pre-condition: both lists are sorted!
- */
-static alpm_list_t *chk_filedifference(alpm_list_t *filesA, alpm_list_t *filesB)
-{
-	alpm_list_t *ret = NULL;
-	alpm_list_t *pA = filesA, *pB = filesB;
-
-	/* if both filesA and filesB have entries, do this loop */
-	while(pA && pB) {
-		const char *strA = pA->data;
-		const char *strB = pB->data;
-		/* skip directories, we don't care about dir conflicts */
-		if(strA[strlen(strA)-1] == '/') {
-			pA = pA->next;
-		} else if(strB[strlen(strB)-1] == '/') {
-			pB = pB->next;
-		} else {
-			int cmp = strcmp(strA, strB);
-			if(cmp < 0) {
-				/* item only in filesA, record it */
-				ret = alpm_list_add(ret, strdup(strA));
-				pA = pA->next;
-			} else if(cmp > 0) {
-				/* item only in fileB, but this means nothing */
-				pB = pB->next;
-			} else {
-				/* item in both, ignore it */
-				pA = pA->next;
-				pB = pB->next;
-			}
-	  }
-	}
-	/* ensure we have completely emptied pA */
-	while(pA) {
+	/* if doing a difference, ensure we have completely emptied pA */
+	while(operation == DIFFERENCE && pA) {
 		const char *strA = pA->data;
 		/* skip directories */
 		if(strA[strlen(strA)-1] != '/') {
@@ -419,7 +392,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(pmdb_t *db, pmtrans_t *trans,
 			if(!p2) {
 				continue;
 			}
-			tmpfiles = chk_fileconflicts(alpm_pkg_get_files(p1), alpm_pkg_get_files(p2));
+			tmpfiles = filelist_operation( alpm_pkg_get_files(p1),
+					alpm_pkg_get_files(p2), INTERSECT);
 
 			if(tmpfiles) {
 				for(k = tmpfiles; k; k = k->next) {
@@ -444,8 +418,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(pmdb_t *db, pmtrans_t *trans,
 		 * is not currently installed, then simply stat the whole filelist */
 		if(dbpkg) {
 			/* older ver of package currently installed */
-			tmpfiles = chk_filedifference(alpm_pkg_get_files(p1),
-					alpm_pkg_get_files(dbpkg));
+			tmpfiles = filelist_operation(alpm_pkg_get_files(p1),
+					alpm_pkg_get_files(dbpkg), DIFFERENCE);
 		} else {
 			/* no version of package currently installed */
 			tmpfiles = alpm_list_strdup(alpm_pkg_get_files(p1));