[pacman-dev] [PATCH] Split filelist_operation function

[Allan McRae]

To improve conflict checking, we will need to make these functions
diverge to an extent where having two separate functions will be
preferable.

Signed-off-by: Allan McRae <allan at archlinux.org>
---
 lib/libalpm/conflict.c | 79 +++++++++++++++++++++++++++++++++-----------------
 1 file changed, 53 insertions(+), 26 deletions(-)

diff --git a/lib/libalpm/conflict.c b/lib/libalpm/conflict.c
index 7494fd7..f3b269f 100644
--- a/lib/libalpm/conflict.c
+++ b/lib/libalpm/conflict.c
@@ -213,18 +213,12 @@ alpm_list_t SYMEXPORT *alpm_checkconflicts(alpm_handle_t *handle,
 	return _alpm_innerconflicts(handle, pkglist);
 }
 
-static const int DIFFERENCE = 0;
-static const int INTERSECT = 1;
-/* Returns a set operation on the provided two lists of files.
+/* Returns the difference of the provided two lists of files.
  * Pre-condition: both lists are sorted!
  * When done, free the list but NOT the contained data.
- *
- * Operations:
- *   DIFFERENCE - a difference operation is performed. filesA - filesB.
- *   INTERSECT - an intersection operation is performed. filesA & filesB.
  */
-static alpm_list_t *filelist_operation(alpm_filelist_t *filesA,
-		alpm_filelist_t *filesB, int operation)
+static alpm_list_t *filelist_difference(alpm_filelist_t *filesA,
+		alpm_filelist_t *filesB)
 {
 	alpm_list_t *ret = NULL;
 	size_t ctrA = 0, ctrB = 0;
@@ -242,26 +236,20 @@ static alpm_list_t *filelist_operation(alpm_filelist_t *filesA,
 		} else {
 			int cmp = strcmp(strA, strB);
 			if(cmp < 0) {
-				if(operation == DIFFERENCE) {
-					/* item only in filesA, qualifies as a difference */
-					ret = alpm_list_add(ret, fileA);
-				}
+				/* item only in filesA, qualifies as a difference */
+				ret = alpm_list_add(ret, fileA);
 				ctrA++;
 			} else if(cmp > 0) {
 				ctrB++;
 			} else {
-				if(operation == INTERSECT) {
-					/* item in both, qualifies as an intersect */
-					ret = alpm_list_add(ret, fileA);
-				}
 				ctrA++;
 				ctrB++;
 			}
-	  }
+		}
 	}
 
-	/* if doing a difference, ensure we have completely emptied pA */
-	while(operation == DIFFERENCE && ctrA < filesA->count) {
+	/* ensure we have completely emptied pA */
+	while(ctrA < filesA->count) {
 		alpm_file_t *fileA = filesA->files + ctrA;
 		const char *strA = fileA->name;
 		/* skip directories */
@@ -274,6 +262,45 @@ static alpm_list_t *filelist_operation(alpm_filelist_t *filesA,
 	return ret;
 }
 
+/* Returns the intersection of the provided two lists of files.
+ * Pre-condition: both lists are sorted!
+ * When done, free the list but NOT the contained data.
+ */
+
+static alpm_list_t *filelist_intersection(alpm_filelist_t *filesA,
+		alpm_filelist_t *filesB)
+{
+	alpm_list_t *ret = NULL;
+	size_t ctrA = 0, ctrB = 0;
+
+	while(ctrA < filesA->count && ctrB < filesB->count) {
+		alpm_file_t *fileA = filesA->files + ctrA;
+		alpm_file_t *fileB = filesB->files + ctrB;
+		const char *strA = fileA->name;
+		const char *strB = fileB->name;
+		/* skip directories, we don't care about them */
+		if(strA[strlen(strA)-1] == '/') {
+			ctrA++;
+		} else if(strB[strlen(strB)-1] == '/') {
+			ctrB++;
+		} else {
+			int cmp = strcmp(strA, strB);
+			if(cmp < 0) {
+				ctrA++;
+			} else if(cmp > 0) {
+				ctrB++;
+			} else {
+				/* item in both, qualifies as an intersect */
+				ret = alpm_list_add(ret, fileA);
+				ctrA++;
+				ctrB++;
+			}
+	  }
+	}
+
+	return ret;
+}
+
 /* Adds alpm_fileconflict_t to a conflicts list. Pass the conflicts list, the
  * conflicting file path, and either two packages or one package and NULL.
  */
@@ -438,8 +465,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 		for(j = i->next; j; j = j->next) {
 			alpm_list_t *common_files;
 			alpm_pkg_t *p2 = j->data;
-			common_files = filelist_operation(alpm_pkg_get_files(p1),
-					alpm_pkg_get_files(p2), INTERSECT);
+			common_files = filelist_intersection(alpm_pkg_get_files(p1),
+					alpm_pkg_get_files(p2));
 
 			if(common_files) {
 				alpm_list_t *k;
@@ -471,8 +498,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 		if(dbpkg) {
 			alpm_list_t *difference;
 			/* older ver of package currently installed */
-			difference = filelist_operation(alpm_pkg_get_files(p1),
-					alpm_pkg_get_files(dbpkg), DIFFERENCE);
+			difference = filelist_difference(alpm_pkg_get_files(p1),
+					alpm_pkg_get_files(dbpkg));
 			tmpfiles.count = alpm_list_count(difference);
 			tmpfiles.files = alpm_list_to_array(difference, tmpfiles.count,
 					sizeof(alpm_file_t));
@@ -604,7 +631,7 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 				if(handle->pm_errno == ALPM_ERR_MEMORY) {
 					FREELIST(conflicts);
 					if(dbpkg) {
-						/* only freed if it was generated from filelist_operation() */
+						/* only freed if it was generated from filelist_difference() */
 						free(tmpfiles.files);
 					}
 					return NULL;
@@ -612,7 +639,7 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 			}
 		}
 		if(dbpkg) {
-			/* only freed if it was generated from filelist_operation() */
+			/* only freed if it was generated from filelist_difference() */
 			free(tmpfiles.files);
 		}
 	}
-- 
1.7.11.2