From: Michael Tremer <michael.tremer@ipfire.org>
Date: Wed, 7 Apr 2021 11:05:10 +0000 (+0000)
Subject: archive: Refactor opening payload
X-Git-Tag: 0.9.28~1285^2~409
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6a642ca842aa7beee56ff262679bd3bcc74be411;p=pakfire.git

archive: Refactor opening payload

This is now using libarchive's internal zero-copy functionality to avoid
copying data back and fourth. This should result in faster extraction
speed.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/libpakfire/archive.c b/src/libpakfire/archive.c
index df3ceaf17..03e87d419 100644
--- a/src/libpakfire/archive.c
+++ b/src/libpakfire/archive.c
@@ -92,20 +92,6 @@ struct _PakfireArchiveSignature {
 	int nrefs;
 };
 
-struct payload_archive_data {
-	struct archive* archive;
-	char buffer[1024 * 1024];
-};
-
-static void configure_archive(struct archive* a) {
-	// All of our packages are tar balls
-	archive_read_support_format_tar(a);
-
-	// They are compressed using XZ or ZSTD
-	archive_read_support_filter_xz(a);
-	archive_read_support_filter_zstd(a);
-}
-
 static int archive_open(PakfireArchive archive, struct archive** a) {
 	*a = archive_read_new();
 	if (!*a)
@@ -168,33 +154,59 @@ static int find_archive_entry(struct archive_entry** entry, struct archive* a, c
 	return 1;
 }
 
-static ssize_t payload_archive_read(struct archive* a, void* client_data, const void** buf) {
-	struct payload_archive_data* data = client_data;
-	*buf = data->buffer;
+static la_ssize_t pakfire_archive_read_callback(struct archive* a,
+		void* client_data, const void** buffer) {
+	struct archive* archive = (struct archive*)client_data;
 
-	return archive_read_data(data->archive, data->buffer, sizeof(data->buffer));
-}
+	size_t len = 0;
+	off_t offset = 0;
 
-static int payload_archive_close(struct archive* a, void* client_data) {
-	struct payload_archive_data* data = client_data;
+	// Try reading the next block (without copying it)
+	int r = archive_read_data_block(archive, buffer, &len, &offset);
 
-	free(data);
+	switch (r) {
+		case ARCHIVE_OK:
+			return len;
+
+		// Return zero to signal that everything was read
+		case ARCHIVE_EOF:
+			return 0;
 
-	return ARCHIVE_OK;
+		// Return -1 on any other errors
+		default:
+			return -1;
+	}
 }
 
-static int payload_archive_open(struct archive** a, struct archive* source_archive) {
-	*a = archive_read_new();
-	configure_archive(*a);
+static struct archive* pakfire_archive_open_payload(PakfireArchive archive, struct archive* a) {
+	// Find the payload
+	struct archive_entry* entry;
+	int r = find_archive_entry(&entry, a, PAKFIRE_ARCHIVE_FN_PAYLOAD);
+	if (r)
+		return NULL;
 
-	struct payload_archive_data* data = calloc(1, sizeof(*data));
-	data->archive = source_archive;
+	// Allocate a new archive object
+	struct archive* payload = archive_read_new();
+	if (!payload)
+		return NULL;
 
-	archive_read_set_callback_data(*a, data);
-	archive_read_set_read_callback(*a, payload_archive_read);
-	archive_read_set_close_callback(*a, payload_archive_close);
+	// All of our packages are tar balls
+	archive_read_support_format_tar(payload);
 
-	return archive_read_open1(*a);
+	// They are compressed using XZ or ZSTD
+	archive_read_support_filter_xz(payload);
+	archive_read_support_filter_zstd(payload);
+
+	// Try opening the payload archive
+	r = archive_read_open2(payload, a, NULL, pakfire_archive_read_callback, NULL, NULL);
+	if (r) {
+		ERROR(archive->pakfire, "Could not open payload archive: %s\n",
+			archive_error_string(payload));
+		archive_read_free(payload);
+		return NULL;
+	}
+
+	return payload;
 }
 
 // Checksum Stuff
@@ -706,7 +718,10 @@ PAKFIRE_EXPORT char* pakfire_archive_get(PakfireArchive archive, const char* nam
 }
 
 static int archive_extract(PakfireArchive archive, struct archive* a, const char* prefix) {
-	struct archive_entry* entry;
+	if (!a)
+		return EINVAL;
+
+	struct archive_entry* entry = NULL;
 	int r;
 	PakfireFile file;
 
@@ -781,22 +796,6 @@ static int archive_extract(PakfireArchive archive, struct archive* a, const char
 	return r;
 }
 
-static struct archive* archive_open_payload(struct archive* a) {
-	struct archive_entry* entry;
-	int r;
-
-	r = find_archive_entry(&entry, a, PAKFIRE_ARCHIVE_FN_PAYLOAD);
-	if (r)
-		return NULL;
-
-	struct archive* payload_archive;
-	r = payload_archive_open(&payload_archive, a);
-	if (r)
-		return NULL;
-
-	return payload_archive;
-}
-
 PAKFIRE_EXPORT int pakfire_archive_read(PakfireArchive archive, const char* filename,
 		char** data, size_t* data_size, int flags) {
 	struct archive* a;
@@ -810,7 +809,7 @@ PAKFIRE_EXPORT int pakfire_archive_read(PakfireArchive archive, const char* file
 	int use_payload = (flags & PAKFIRE_ARCHIVE_USE_PAYLOAD);
 
 	if (use_payload) {
-		pa = archive_open_payload(a);
+		pa = pakfire_archive_open_payload(archive, a);
 
 		// Strip leading / from filenames, because the payload does
 		// not have leading slashes.
@@ -878,7 +877,7 @@ PAKFIRE_EXPORT int pakfire_archive_extract(PakfireArchive archive, const char* p
 	DEBUG(archive->pakfire, "Extracting %s to %s\n", archive->path, prefix);
 
 	if (use_payload)
-		pa = archive_open_payload(a);
+		pa = pakfire_archive_open_payload(archive, a);
 
 	r = archive_extract(archive, use_payload ? pa : a,
 		prefix ? prefix : pakfire_get_path(archive->pakfire));