Enable inverted patterns in NoExtract and NoUpgrade.

It is now possible to invert patterns in NoExtract and NoUpgrade.
This feature allows users to whitelist certain files that were
previously blacklisted by another entry.

Signed-off-by: Allan McRae <allan@archlinux.org>

4 files changed, 42 insertions, 4 deletions

diff --git a/doc/pacman.conf.5.txt b/doc/pacman.conf.5.txt
index 83a399e1..049faee2 100644
--- a/doc/pacman.conf.5.txt
+++ b/doc/pacman.conf.5.txt
@@ -128,7 +128,10 @@ Options
 	'.pacnew' extension.
 	These files refer to files in the package archive, so do not include the
 	leading slash (the RootDir) when specifying them. Shell-style glob patterns
-	are allowed.
+	are allowed. It is possible to invert matches by prepending a file with
+	an exclamation mark. Inverted files will result in previously blacklisted
+	files being whitelisted again. Subsequent matches will override previous
+	ones. A leading literal exclamation mark or backslash needs to be escaped.
 
 *NoExtract =* file ...::
 	All files listed with a `NoExtract` directive will never be extracted from
@@ -138,7 +141,10 @@ Options
 	from the 'apache' package.
 	These files refer to files in the package archive, so do not include the
 	leading slash (the RootDir) when specifying them. Shell-style glob patterns
-	are allowed.
+	are allowed. It is possible to invert matches by prepending a file with
+	an exclamation mark. Inverted files will result in previously blacklisted
+	files being whitelisted again. Subsequent matches will override previous
+	ones. A leading literal exclamation mark or backslash needs to be escaped.
 
 *CleanMethod =* KeepInstalled &| KeepCurrent::
 	If set to `KeepInstalled` (the default), the '-Sc' operation will clean
diff --git a/lib/libalpm/add.c b/lib/libalpm/add.c
index cab04a8b..3d0cf55a 100644
--- a/lib/libalpm/add.c
+++ b/lib/libalpm/add.c
@@ -183,7 +183,7 @@ static int extract_single_file(alpm_handle_t *handle, struct archive *archive,
 	}
 
 	/* if a file is in NoExtract then we never extract it */
-	if(alpm_list_find(handle->noextract, entryname, _alpm_fnmatch)) {
+	if(_alpm_fnmatch_patterns(handle->noextract, entryname) == 0) {
 		_alpm_log(handle, ALPM_LOG_DEBUG, "%s is in NoExtract,"
 				" skipping extraction of %s\n",
 				entryname, filename);
@@ -245,7 +245,7 @@ static int extract_single_file(alpm_handle_t *handle, struct archive *archive,
 		} else {
 			/* case 3: */
 			/* if file is in NoUpgrade, don't touch it */
-			if(alpm_list_find(handle->noupgrade, entryname, _alpm_fnmatch)) {
+			if(_alpm_fnmatch_patterns(handle->noupgrade, entryname) == 0) {
 				notouch = 1;
 			} else {
 				alpm_backup_t *backup;
diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
index f84fb666..15c1a67c 100644
--- a/lib/libalpm/util.c
+++ b/lib/libalpm/util.c
@@ -1249,6 +1249,37 @@ int _alpm_access(alpm_handle_t *handle, const char *dir, const char *file, int a
 	return ret;
 }
 
+/** Checks whether a string matches at least one shell wildcard pattern.
+ * Checks for matches with fnmatch. Matches are inverted by prepending
+ * patterns with an exclamation mark. Preceding exclamation marks may be
+ * escaped. Subsequent matches override previous ones.
+ * @param patterns patterns to match against
+ * @param string string to check against pattern
+ * @return 0 if string matches pattern, negative if they don't match and
+ * positive if the last match was inverted
+ */
+int _alpm_fnmatch_patterns(alpm_list_t *patterns, const char *string)
+{
+	alpm_list_t *i;
+	char *pattern;
+	short inverted;
+
+	for(i = alpm_list_last(patterns); i; i = alpm_list_previous(i)) {
+		pattern = i->data;
+
+		inverted = pattern[0] == '!';
+		if(inverted || pattern[0] == '\\') {
+			pattern++;
+		}
+
+		if(_alpm_fnmatch(pattern, string) == 0) {
+			return inverted;
+		}
+	}
+
+	return -1;
+}
+
 /** Checks whether a string matches a shell wildcard pattern.
  * Wrapper around fnmatch.
  * @param pattern pattern to match against
diff --git a/lib/libalpm/util.h b/lib/libalpm/util.h
index 56031f3e..24b7c229 100644
--- a/lib/libalpm/util.h
+++ b/lib/libalpm/util.h
@@ -140,6 +140,7 @@ alpm_time_t _alpm_parsedate(const char *line);
 int _alpm_raw_cmp(const char *first, const char *second);
 int _alpm_raw_ncmp(const char *first, const char *second, size_t max);
 int _alpm_access(alpm_handle_t *handle, const char *dir, const char *file, int amode);
+int _alpm_fnmatch_patterns(alpm_list_t *patterns, const char *string);
 int _alpm_fnmatch(const void *pattern, const void *string);
 
 #ifndef HAVE_STRSEP