io,url,db: support for if-modified-since

6 files changed, 81 insertions, 53 deletions

diff --git a/src/apk_defines.h b/src/apk_defines.h
index 95b70de..d27bad4 100644
--- a/src/apk_defines.h
+++ b/src/apk_defines.h
@@ -32,6 +32,12 @@
 #define NULL 0L
 #endif
 
+static inline void *ERR_PTR(long error) { return (void*) error; }
+static inline void *ERR_CAST(const void *ptr) { return (void*) ptr; }
+static inline int PTR_ERR(const void *ptr) { return (int)(long) ptr; }
+static inline int IS_ERR(const void *ptr) { return (unsigned long)ptr >= (unsigned long)-4095; }
+static inline int IS_ERR_OR_NULL(const void *ptr) { return IS_ERR(ptr) || !ptr; }
+
 #if defined __GNUC__ && __GNUC__ == 2 && __GNUC_MINOR__ < 96
 #define __builtin_expect(x, expected_value) (x)
 #endif
diff --git a/src/apk_io.h b/src/apk_io.h
index c61fc6e..82102aa 100644
--- a/src/apk_io.h
+++ b/src/apk_io.h
@@ -14,6 +14,7 @@
 #include <sys/types.h>
 #include <openssl/evp.h>
 #include <fcntl.h>
+#include <time.h>
 
 #include "apk_defines.h"
 #include "apk_blob.h"
@@ -78,7 +79,7 @@ struct apk_ostream *apk_ostream_counter(off_t *);
 struct apk_istream *apk_istream_from_fd_pid(int fd, pid_t pid, int (*translate_status)(int));
 struct apk_istream *apk_istream_from_file(int atfd, const char *file);
 struct apk_istream *apk_istream_from_file_gz(int atfd, const char *file);
-struct apk_istream *apk_istream_from_fd_url(int atfd, const char *url);
+struct apk_istream *apk_istream_from_fd_url_if_modified(int atfd, const char *url, time_t since);
 struct apk_istream *apk_istream_from_url_gz(const char *url);
 size_t apk_istream_skip(struct apk_istream *istream, size_t size);
 
@@ -92,13 +93,21 @@ static inline struct apk_istream *apk_istream_from_fd(int fd)
 }
 static inline struct apk_istream *apk_istream_from_url(const char *url)
 {
-	return apk_istream_from_fd_url(AT_FDCWD, url);
+	return apk_istream_from_fd_url_if_modified(AT_FDCWD, url, 0);
+}
+static inline struct apk_istream *apk_istream_from_fd_url(int atfd, const char *url)
+{
+	return apk_istream_from_fd_url_if_modified(atfd, url, 0);
+}
+static inline struct apk_istream *apk_istream_from_url_if_modified(const char *url, time_t since)
+{
+	return apk_istream_from_fd_url_if_modified(AT_FDCWD, url, since);
 }
 
 struct apk_bstream *apk_bstream_from_istream(struct apk_istream *istream);
 struct apk_bstream *apk_bstream_from_fd_pid(int fd, pid_t pid, int (*translate_status)(int));
 struct apk_bstream *apk_bstream_from_file(int atfd, const char *file);
-struct apk_bstream *apk_bstream_from_fd_url(int atfd, const char *url);
+struct apk_bstream *apk_bstream_from_fd_url_if_modified(int atfd, const char *url, time_t since);
 struct apk_bstream *apk_bstream_tee(struct apk_bstream *from, int atfd, const char *to,
 				    apk_progress_cb cb, void *cb_ctx);
 
@@ -109,7 +118,15 @@ static inline struct apk_bstream *apk_bstream_from_fd(int fd)
 
 static inline struct apk_bstream *apk_bstream_from_url(const char *url)
 {
-	return apk_bstream_from_fd_url(AT_FDCWD, url);
+	return apk_bstream_from_fd_url_if_modified(AT_FDCWD, url, 0);
+}
+static inline struct apk_bstream *apk_bstream_from_fd_url(int fd, const char *url)
+{
+	return apk_bstream_from_fd_url_if_modified(fd, url, 0);
+}
+static inline struct apk_bstream *apk_bstream_from_url_if_modified(const char *url, time_t since)
+{
+	return apk_bstream_from_fd_url_if_modified(AT_FDCWD, url, since);
 }
 
 struct apk_ostream *apk_ostream_to_fd(int fd);
diff --git a/src/database.c b/src/database.c
index ef9f73c..3962a8e 100644
--- a/src/database.c
+++ b/src/database.c
@@ -605,6 +605,7 @@ int apk_cache_download(struct apk_database *db, struct apk_repository *repo,
 		       struct apk_package *pkg, int verify,
 		       apk_progress_cb cb, void *cb_ctx)
 {
+	struct stat st;
 	struct apk_istream *is;
 	struct apk_bstream *bs;
 	struct apk_sign_ctx sctx;
@@ -618,40 +619,42 @@ int apk_cache_download(struct apk_database *db, struct apk_repository *repo,
 		r = apk_pkg_format_cache_pkg(b, pkg);
 	else
 		r = apk_repo_format_cache_index(b, repo);
-	if (r < 0)
-		return r;
+	if (r < 0) return r;
 
 	r = apk_repo_format_real_url(db, repo, pkg, url, sizeof(url));
-	if (r < 0)
-		return r;
+	if (r < 0) return r;
 
-	apk_message("fetch %s", url);
+	if (fstatat(db->cache_fd, cacheitem, &st, 0) != 0) st.st_mtime = 0;
 
-	if (apk_flags & APK_SIMULATE)
-		return 0;
+	apk_message("fetch %s", url);
 
-	if (cb)
-		cb(cb_ctx, 0);
+	if (apk_flags & APK_SIMULATE) return 0;
+	if (cb) cb(cb_ctx, 0);
 
 	if (verify != APK_SIGN_NONE) {
 		apk_sign_ctx_init(&sctx, APK_SIGN_VERIFY, NULL, db->keys_fd);
-		bs = apk_bstream_from_url(url);
+		bs = apk_bstream_from_url_if_modified(url, st.st_mtime);
 		bs = apk_bstream_tee(bs, db->cache_fd, tmpcacheitem, cb, cb_ctx);
 		is = apk_bstream_gunzip_mpart(bs, apk_sign_ctx_mpart_cb, &sctx);
-		if (is) r = apk_tar_parse(is, apk_sign_ctx_verify_tar, &sctx, FALSE, &db->id_cache);
-		else r = -errno;
+		if (!IS_ERR_OR_NULL(is))
+			r = apk_tar_parse(is, apk_sign_ctx_verify_tar, &sctx, FALSE, &db->id_cache);
+		else
+			r = PTR_ERR(is) ?: -EIO;
 		apk_sign_ctx_free(&sctx);
 	} else {
-		is = apk_istream_from_url(url);
-		fd = openat(db->cache_fd, tmpcacheitem, O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0644);
+		is = apk_istream_from_url_if_modified(url, st.st_mtime);
+		if (!IS_ERR_OR_NULL(is)) {
+			fd = openat(db->cache_fd, tmpcacheitem, O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0644);
+			if (fd < 0) r = -errno;
+		} else fd = -1, r = PTR_ERR(is) ?: -EIO;
+
 		if (fd >= 0) {
 			r = apk_istream_splice(is, fd, APK_SPLICE_ALL, cb, cb_ctx);
 			close(fd);
-		} else {
-			r = -errno;
 		}
 	}
-	if (is) is->close(is);
+	if (!IS_ERR_OR_NULL(is)) is->close(is);
+	if (r == -EALREADY) return 0;
 	if (r < 0) {
 		unlinkat(db->cache_fd, tmpcacheitem, 0);
 		return r;
@@ -659,7 +662,6 @@ int apk_cache_download(struct apk_database *db, struct apk_repository *repo,
 
 	if (renameat(db->cache_fd, tmpcacheitem, db->cache_fd, cacheitem) < 0)
 		return -errno;
-
 	return 0;
 }
 
diff --git a/src/gunzip.c b/src/gunzip.c
index 944132e..45e3b3c 100644
--- a/src/gunzip.c
+++ b/src/gunzip.c
@@ -149,7 +149,7 @@ struct apk_istream *apk_bstream_gunzip_mpart(struct apk_bstream *bs,
 {
 	struct apk_gzip_istream *gis;
 
-	if (!bs) return NULL;
+	if (IS_ERR_OR_NULL(bs)) return ERR_CAST(bs);
 
 	gis = malloc(sizeof(struct apk_gzip_istream));
 	if (!gis) goto err;
@@ -233,8 +233,7 @@ struct apk_ostream *apk_ostream_gzip(struct apk_ostream *output)
 {
 	struct apk_gzip_ostream *gos;
 
-	if (output == NULL)
-		return NULL;
+	if (IS_ERR_OR_NULL(output)) return ERR_CAST(output);
 
 	gos = malloc(sizeof(struct apk_gzip_ostream));
 	if (gos == NULL)
diff --git a/src/io.c b/src/io.c
index c713107..95af88d 100644
--- a/src/io.c
+++ b/src/io.c
@@ -83,8 +83,7 @@ struct apk_istream *apk_istream_from_fd_pid(int fd, pid_t pid, int (*translate_s
 {
 	struct apk_fd_istream *fis;
 
-	if (fd < 0)
-		return NULL;
+	if (fd < 0) return NULL;
 
 	fis = malloc(sizeof(struct apk_fd_istream));
 	if (fis == NULL) {
@@ -108,8 +107,7 @@ struct apk_istream *apk_istream_from_file(int atfd, const char *file)
 	int fd;
 
 	fd = openat(atfd, file, O_RDONLY | O_CLOEXEC);
-	if (fd < 0)
-		return NULL;
+	if (fd < 0) return NULL;
 
 	return apk_istream_from_fd(fd);
 }
@@ -272,9 +270,10 @@ struct apk_bstream *apk_bstream_from_istream(struct apk_istream *istream)
 {
 	struct apk_istream_bstream *isbs;
 
+	if (IS_ERR_OR_NULL(istream)) return ERR_CAST(istream);
+
 	isbs = malloc(sizeof(struct apk_istream_bstream));
-	if (isbs == NULL)
-		return NULL;
+	if (isbs == NULL) return NULL;
 
 	isbs->bs = (struct apk_bstream) {
 		.read = is_bs_read,
@@ -331,12 +330,10 @@ static struct apk_bstream *apk_mmap_bstream_from_fd(int fd)
 	struct stat st;
 	void *ptr;
 
-	if (fstat(fd, &st) < 0)
-		return NULL;
+	if (fstat(fd, &st) < 0) return NULL;
 
 	ptr = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
-	if (ptr == MAP_FAILED)
-		return NULL;
+	if (ptr == MAP_FAILED) return NULL;
 
 	mbs = malloc(sizeof(struct apk_mmap_bstream));
 	if (mbs == NULL) {
@@ -361,8 +358,7 @@ struct apk_bstream *apk_bstream_from_fd_pid(int fd, pid_t pid, int (*translate_s
 {
 	struct apk_bstream *bs;
 
-	if (fd < 0)
-		return NULL;
+	if (fd < 0) return NULL;
 
 	if (pid == 0) {
 		bs = apk_mmap_bstream_from_fd(fd);
@@ -378,8 +374,7 @@ struct apk_bstream *apk_bstream_from_file(int atfd, const char *file)
 	int fd;
 
 	fd = openat(atfd, file, O_RDONLY | O_CLOEXEC);
-	if (fd < 0)
-		return NULL;
+	if (fd < 0) return NULL;
 
 	return apk_bstream_from_fd(fd);
 }
@@ -427,7 +422,7 @@ struct apk_bstream *apk_bstream_tee(struct apk_bstream *from, int atfd, const ch
 	struct apk_tee_bstream *tbs;
 	int fd;
 
-	if (!from) return NULL;
+	if (IS_ERR_OR_NULL(from)) return ERR_CAST(from);
 
 	fd = openat(atfd, to, O_CREAT | O_RDWR | O_TRUNC | O_CLOEXEC,
 		    S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
@@ -831,8 +826,8 @@ int apk_move_file(int atfd, const char *from, const char *to)
 		return -errno;
 
 	is = apk_istream_from_file(atfd, from);
-	if (is == NULL)
-		return -ENOENT;
+	if (IS_ERR(is)) return PTR_ERR(is);
+	if (!is) return -ENOENT;
 
 	tofd = openat(atfd, to, O_CREAT | O_RDWR | O_TRUNC | O_CLOEXEC,
 		      S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
diff --git a/src/url.c b/src/url.c
index f3c6631..80f0a60 100644
--- a/src/url.c
+++ b/src/url.c
@@ -63,34 +63,43 @@ static void fetch_close(void *stream)
 	free(fis);
 }
 
-static struct apk_istream *apk_istream_fetch(const char *url)
+static struct apk_istream *apk_istream_fetch(const char *url, time_t since)
 {
 	struct apk_fetch_istream *fis;
+	struct url *u;
 	fetchIO *io;
 
-	io = fetchGetURL(url, "");
-	if (!io) return NULL;
-
-	fis = malloc(sizeof(*fis));
-	if (!fis) {
-		fetchIO_close(io);
+	u = fetchParseURL(url);
+	if (!u) return NULL;
+	u->last_modified = since;
+	io = fetchGet(u, "i");
+	fetchFreeURL(u);
+	if (!io) {
+		if (fetchLastErrCode == FETCH_UNCHANGED) return ERR_PTR(-EALREADY);
 		return NULL;
 	}
 
+	fis = malloc(sizeof(*fis));
+	if (!fis) goto err;
+
 	*fis = (struct apk_fetch_istream) {
 		.is.read = fetch_read,
 		.is.close = fetch_close,
 		.fetchIO = io,
 	};
+	fetchFreeURL(u);
 
 	return &fis->is;
+err:
+	if (io) fetchIO_close(io);
+	return NULL;
 }
 
-struct apk_istream *apk_istream_from_fd_url(int atfd, const char *url)
+struct apk_istream *apk_istream_from_fd_url_if_modified(int atfd, const char *url, time_t since)
 {
 	if (apk_url_local_file(url) != NULL)
 		return apk_istream_from_file(atfd, apk_url_local_file(url));
-	return apk_istream_fetch(url);
+	return apk_istream_fetch(url, since);
 }
 
 struct apk_istream *apk_istream_from_url_gz(const char *file)
@@ -98,9 +107,9 @@ struct apk_istream *apk_istream_from_url_gz(const char *file)
 	return apk_bstream_gunzip(apk_bstream_from_url(file));
 }
 
-struct apk_bstream *apk_bstream_from_fd_url(int atfd, const char *url)
+struct apk_bstream *apk_bstream_from_fd_url_if_modified(int atfd, const char *url, time_t since)
 {
 	if (apk_url_local_file(url) != NULL)
 		return apk_bstream_from_file(atfd, apk_url_local_file(url));
-	return apk_bstream_from_istream(apk_istream_fetch(url));
+	return apk_bstream_from_istream(apk_istream_fetch(url, since));
 }