libxbps: [unpack] only extract files if they have been modified.

NEWS

@@ -1,5 +1,9 @@
 xbps-0.10.0 (???):
 
+ * libxbps: when updating packages, only files that have been modified
+   (compared to current installed file) are now unpacked. This should
+   save some writes to storage and make the process a bit smoother as well.
+
  * Moved install transaction code to libxbps. The API has been extended
    with xbps_transaction_commit() which expects the transaction dictionary
    as its argument. This function will execute transaction tasks, like

include/xbps_api.h

@@ -55,7 +55,7 @@
  */
 #define XBPS_PKGINDEX_VERSION	"1.2"
 
-#define XBPS_API_VERSION	"20110729"
+#define XBPS_API_VERSION	"20110731"
 #define XBPS_VERSION		"0.10.0"
 
 /**
@@ -1430,7 +1430,7 @@ char *xbps_file_hash(const char *file);
  * @return The sha256 hash string if found, NULL otherwise
  * and errno is set appropiately.
  */
-const char *xbps_file_hash_from_dictionary(prop_dictionary_t d,
+const char *xbps_file_hash_dictionary(prop_dictionary_t d,
 				      const char *key,
 				      const char *file);
 
@@ -1446,6 +1446,20 @@ const char *xbps_file_hash_from_dictionary(prop_dictionary_t d,
  */
 int xbps_file_hash_check(const char *file, const char *sha256);
 
+/**
+ * Checks if \a file matches the sha256 hash specified in the array
+ * with key \a key in the proplib dictionary \a d.
+ *
+ * @param[in] d Proplib dictionary to look in.
+ * @param[in] key Proplib array key to match for file.
+ * @param[in] file Pathname to a file.
+ *
+ * @return 0 if hash is matched, -1 on error and 1 if no match.
+ */
+int xbps_file_hash_check_dictionary(prop_dictionary_t d,
+				    const char *key,
+				    const char *file);
+
 /**
  * Checks if a package is currently installed by matching a package
  * pattern string.

lib/package_unpack.c

@@ -157,6 +157,7 @@ unpack_archive(prop_dictionary_t pkg_repod,
 {
 	prop_dictionary_t propsd = NULL, filesd = NULL, old_filesd = NULL;
 	prop_array_t array;
+	const struct stat *entry_statp;
 	struct archive_entry *entry;
 	size_t nmetadata = 0, entry_idx = 0;
 	const char *entry_pname, *transact;
@@ -200,6 +201,7 @@ unpack_archive(prop_dictionary_t pkg_repod,
 	 * Process the archive files.
 	 */
 	while (archive_read_next_header(ar, &entry) == ARCHIVE_OK) {
+		entry_statp = archive_entry_stat(entry);
 		entry_pname = archive_entry_pathname(entry);
 		flags = set_extract_flags();
 
@@ -324,6 +326,7 @@ unpack_archive(prop_dictionary_t pkg_repod,
 		xhp->xucd->entry_total_count +=
 		    (ssize_t)prop_array_count(array);
 
+		if (update && S_ISREG(entry_statp->st_mode)) {
 			/*
 			 * Handle configuration files. Check if current entry is
 			 * a configuration file and take action if required. Skip
@@ -352,6 +355,28 @@ unpack_archive(prop_dictionary_t pkg_repod,
 					RUN_PROGRESS_CB();
 					continue;
 				}
+			} else {
+				/*
+				 * Current entry is not a configuration file,
+				 * check if installed file matches sha256 hash.
+				 * If true, there is no need to extract it.
+				 */
+				rv = xbps_file_hash_check_dictionary(filesd,
+				    "files", entry_pname);
+				if (rv == -1) {
+					xbps_dbg_printf("%s-%s: failed to check"
+					    " hash for `%s': %s\n", pkgname,
+					    version, entry_pname,
+					    strerror(errno));
+					/* error */
+					goto out;
+				} else if (rv == 0) {
+					/* hash match, skip */
+					archive_read_data_skip(ar);
+					RUN_PROGRESS_CB();
+					continue;
+				}
+			}
 		}
 		/*
 		 * Extract entry from archive.

lib/util_hash.c

@@ -137,7 +137,7 @@ xbps_file_hash_check(const char *file, const char *sha256)
 }
 
 const char *
-xbps_file_hash_from_dictionary(prop_dictionary_t d,
+xbps_file_hash_dictionary(prop_dictionary_t d,
 			  const char *key,
 			  const char *file)
 {
@@ -152,8 +152,10 @@ xbps_file_hash_from_dictionary(prop_dictionary_t d,
 	curfile = sha256 = NULL;
 
 	iter = xbps_array_iter_from_dict(d, key);
-	if (iter == NULL)
+	if (iter == NULL) {
+		errno = ENOENT;
 		return NULL;
+	}
 	while ((obj = prop_object_iterator_next(iter)) != NULL) {
 		prop_dictionary_get_cstring_nocopy(obj,
 		    "file", &curfile);
@@ -170,3 +172,32 @@ xbps_file_hash_from_dictionary(prop_dictionary_t d,
 
 	return sha256;
 }
+
+int
+xbps_file_hash_check_dictionary(prop_dictionary_t d,
+				const char *key,
+				const char *file)
+{
+	const char *sha256d;
+	int rv;
+
+	assert(d != NULL);
+	assert(key != NULL);
+	assert(file != NULL);
+
+	sha256d = xbps_file_hash_dictionary(d, key, file);
+	if (sha256d == NULL) {
+		if (errno == ENOENT)
+			return 1; /* no match, file not found */
+
+		return -1; /* error */
+	}
+
+	rv = xbps_file_hash_check(file, sha256d);
+	if (rv == 0)
+		return 0; /* matched */
+	else if (rv == ERANGE || rv == ENOENT)
+		return 1; /* no match */
+	else
+		return -1; /* error */
+}