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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/memory/scoped_ptr.h"
#include "base/stl_util.h"
#include "crypto/secure_hash.h"
#include "crypto/sha2.h"
#include "extensions/browser/content_hash_tree.h"
#include "testing/gtest/include/gtest/gtest.h"
using crypto::kSHA256Length;
using crypto::SecureHash;
// Helper to return a fake sha256 signature based on a seed.
static std::string FakeSignatureWithSeed(int seed) {
std::string input;
for (int i = 0; i < seed * 3; i++) {
input.push_back(static_cast<char>(((i + 19) * seed) % 256));
}
return crypto::SHA256HashString(input);
}
namespace extensions {
TEST(ContentHashTreeTest, HashTreeBasics) {
std::vector<std::string> nodes;
// Empty array.
EXPECT_EQ(std::string(), ComputeTreeHashRoot(nodes, 16));
// One node.
std::string node1 = FakeSignatureWithSeed(1);
nodes.push_back(node1);
EXPECT_EQ(node1, ComputeTreeHashRoot(nodes, 16));
// Two nodes.
std::string node2 = FakeSignatureWithSeed(2);
nodes.push_back(node2);
std::string expected(kSHA256Length, 0);
scoped_ptr<SecureHash> hash(SecureHash::Create(SecureHash::SHA256));
hash->Update(node1.data(), node1.size());
hash->Update(node2.data(), node2.size());
hash->Finish(string_as_array(&expected), expected.size());
EXPECT_EQ(expected, ComputeTreeHashRoot(nodes, 16));
}
TEST(ContentHashTreeTest, HashTreeMultipleLevels) {
std::vector<std::string> nodes;
for (int i = 0; i < 3; i++) {
std::string node;
nodes.push_back(FakeSignatureWithSeed(i));
}
// First try a test where our branch factor is >= 3, so we expect the result
// to be the hash of all 3 concatenated together. E.g the expected top hash
// should be 4 in the following diagram:
// 4
// 1 2 3
std::string expected =
crypto::SHA256HashString(nodes[0] + nodes[1] + nodes[2]);
EXPECT_EQ(expected, ComputeTreeHashRoot(nodes, 4));
// Now try making the branch factor be 2, so that we
// should get the following:
// 6
// 4 5
// 1 2 3
// where 4 is the hash of 1 and 2, 5 is the hash of 3, and 6 is the
// hash of 4 and 5.
std::string hash_of_first_2 = crypto::SHA256HashString(nodes[0] + nodes[1]);
std::string hash_of_third = crypto::SHA256HashString(nodes[2]);
expected = crypto::SHA256HashString(hash_of_first_2 + hash_of_third);
EXPECT_EQ(expected, ComputeTreeHashRoot(nodes, 2));
}
} // namespace extensions
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