add support for verified files

1 files changed, 57 insertions, 1 deletions

diff --git a/lib/include/net.h b/lib/include/net.h
index d5f1482..5ee7fc6 100644
--- a/lib/include/net.h
+++ b/lib/include/net.h
@@ -3,6 +3,62 @@
 
 #include "arena.h"
 
-int vl_net_ensure_cached(vl_arena *arena, const char *url, const char *target_path);
+enum {
+  /* The operation completed successfully */
+  NET_OK = 0,
+
+  /* There was some kind of error relating to I/O on the local system */
+  NET_EIO = -1,
+
+  /* There was some kind of network error downloading the file. */
+  NET_ENETWORK = -2,
+
+  /* The server gave us a bad status code while downloading the file. */
+  NET_ESTATUS = -3,
+
+  /* An unrecoverable integrity error occurred. */
+  NET_EINTEGRITY = -4,
+
+  /* An unspecified error occurred. */
+  NET_EUNSPEC = -5,
+
+  /* An unspecified (remote) error occurred. */
+  NET_EREMOTEUNSPEC = -6
+};
+
+enum {
+  VERIFY_SIZE = 1u,
+  VERIFY_SHA1 = 2u
+};
+
+/* Ensures the latest version of the file available at 'url' is downloaded to 'target_path'.
+ * Will avoid downloading the file if it hasn't changed.
+ *
+ * Never returns NET_EINTEGRITY. */
+int vl_net_ensure_cached(vl_arena *scratch, const char *url, const char *target_path);
+
+/* Will verify that the file at 'target_path' hasn't been tampered with since being updated
+ * by vl_net_ensure_cached.
+ *
+ * Returns NET_EIO if the file doesn't exist or couldn't be read.
+ * Returns NET_EINTEGRITY if the file on disk doesn't match. */
+int vl_net_verify_cached(vl_arena *scratch, const char *target_path);
+
+/* Downloads a file for which you know the integrity information (SHA1 and/or size) from 'url' to
+ * 'target_path'. Will not download the file if the file already exists with correct SHA1 and size
+ * (as specified).
+ *
+ * Pass variadic arguments in the following order:
+ * - size_t size (if VERIFY_SIZE is set)
+ * - const uint8_t *hash (if VERIFY_SHA1 is set)
+ *
+ * Returns NET_EINTEGRITY if the file at 'url' doesn't match the provided integrity information. */
+int vl_net_ensure_verified(const char *url, const char *target_path, unsigned flags, ...);
+
+/* See vl_net_ensure_verified for information on the variadic argument list.
+ *
+ * Returns NET_EINTEGRITY if the file at 'target_path' doesn't match the provided integrity information.
+ * Returns NET_EIO if the downloaded file is not readable or could not be verified due to an I/O issue. */
+int vl_net_verify(const char *target_path, unsigned flags, ...);
 
 #endif