Method readBlock

fdbrpc/AsyncFileEncrypted.actor.cpp:48–59

	// Read a single block of size ENCRYPTION_BLOCK_SIZE bytes, and decrypt.
	ACTOR static Future<Standalone<StringRef>> readBlock(AsyncFileEncrypted* self, uint32_t block) {
		state Arena arena;
		state unsigned char* encrypted = new (arena) unsigned char[FLOW_KNOBS->ENCRYPTION_BLOCK_SIZE];
		int bytes = wait(uncancellable(holdWhile(arena,
		                                         self->file->read(encrypted,
		                                                          FLOW_KNOBS->ENCRYPTION_BLOCK_SIZE,
		                                                          FLOW_KNOBS->ENCRYPTION_BLOCK_SIZE * block))));
		StreamCipherKey const* cipherKey = StreamCipherKey::getGlobalCipherKey();
		DecryptionStreamCipher decryptor(cipherKey, self->getIV(block));
		auto decrypted = decryptor.decrypt(encrypted, bytes, arena);
		return Standalone<StringRef>(decrypted, arena);
	}

	ACTOR static Future<int> read(Reference<AsyncFileEncrypted> self, void* data, int length, int64_t offset) {
		state const uint32_t firstBlock = offset / FLOW_KNOBS->ENCRYPTION_BLOCK_SIZE;