Define canonical avatar names and size limits

src/chat/chat_member.c

@@ -9,6 +9,7 @@
 #include "chat_member.h"
 #include "chat_event.h"
 #include "member_sync.h"
+#include "../member_files/protocol.h"
 
 #include "../utun_instance.h"
 #include "../routing_layer/topo_group.h"

src/member_files/protocol.c

@@ -3,6 +3,12 @@
 #include <string.h>
 #include <ctype.h>
 
+int mf_avatar_file_valid(const char* file) {
+    if (!file || strlen(file) != 68 || strcmp(file + 64, ".png")) return 0;
+    for (unsigned i = 0; i < 64; i++) if (!((file[i] >= '0' && file[i] <= '9') || (file[i] >= 'a' && file[i] <= 'f'))) return 0;
+    return 1;
+}
+
 uint64_t mf_get64(const uint8_t* p) {
     uint64_t v = 0;
     for (unsigned i = 0; i < 8; i++) v |= (uint64_t)p[i] << (8 * i);

src/member_files/protocol.h

@@ -22,6 +22,8 @@ extern "C" {
 #define MF_WIRE_MAX (MF_WIRE_HEADER + 2 * MF_PATH_MAX + MF_BLOCK_SIZE)
 #define MF_ENTRY_HEADER 35
 #define MF_QUOTA_BYTES 40 /* used/limit/reserved в байтах, files/directories; пять u64 LE */
+#define MF_AVATAR_MAX_BYTES (1024 * 1024)
+int mf_avatar_file_valid(const char* file);
 #define MF_IDLE_TB 100000ULL /* 10 секунд */
 #define MF_REQUEST 1
 #define MF_RESPONSE 2