[Downloads] Rework how hashes are calculated for download files.

crypto/secure_hash_unittest.cc

 // Copyright (c) 2012 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 "crypto/secure_hash.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
-#include "base/pickle.h"
 #include "crypto/sha2.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(SecureHashTest, TestUpdate) {
   // Example B.3 from FIPS 180-2: long message.
   std::string input3(500000, 'a');  // 'a' repeated half a million times
   int expected3[] = { 0xcd, 0xc7, 0x6e, 0x5c,
                       0x99, 0x14, 0xfb, 0x92,
                       0x81, 0xa1, 0xc7, 0xe2,
                       0x84, 0xd7, 0x3e, 0x67,
                       0xf1, 0x80, 0x9a, 0x48,
                       0xa4, 0x97, 0x20, 0x0e,
                       0x04, 0x6d, 0x39, 0xcc,
                       0xc7, 0x11, 0x2c, 0xd0 };
 
   uint8_t output3[crypto::kSHA256Length];
 
   scoped_ptr<crypto::SecureHash> ctx(crypto::SecureHash::Create(
       crypto::SecureHash::SHA256));
   ctx->Update(input3.data(), input3.size());
   ctx->Update(input3.data(), input3.size());
 
   ctx->Finish(output3, sizeof(output3));
   for (size_t i = 0; i < crypto::kSHA256Length; i++)
     EXPECT_EQ(expected3[i], static_cast<int>(output3[i]));
 }
 
-// Save the crypto state mid-stream, and create another instance with the
-// saved state.  Then feed the same data afterwards to both.
-// When done, both should have the same hash value.
-TEST(SecureHashTest, TestSerialization) {
+TEST(SecureHashTest, TestClone) {
   std::string input1(10001, 'a');  // 'a' repeated 10001 times
-  std::string input2(10001, 'b');  // 'b' repeated 10001 times
-  std::string input3(10001, 'c');  // 'c' repeated 10001 times
-  std::string input4(10001, 'd');  // 'd' repeated 10001 times
-  std::string input5(10001, 'e');  // 'e' repeated 10001 times
+  std::string input2(10001, 'd');  // 'd' repeated 10001 times
+
+  uint8_t expected_sha256_hash_of_input1[crypto::kSHA256Length] = {
+      0x0c, 0xab, 0x99, 0xa0, 0x58, 0x60, 0x0f, 0xfa, 0xad, 0x12, 0x92,
+      0xd0, 0xc5, 0x3c, 0x05, 0x48, 0xeb, 0xaf, 0x88, 0xdd, 0x1d, 0x01,
+      0x03, 0x03, 0x45, 0x70, 0x5f, 0x01, 0x8a, 0x81, 0x39, 0x09
+  };
+  uint8_t expected_sha256_hash_of_inputs1and2[crypto::kSHA256Length] = {
+      0x4c, 0x8e, 0x26, 0x5a, 0xc3, 0x85, 0x1f, 0x1f, 0xa5, 0x04, 0x1c,
+      0xc7, 0x88, 0x53, 0x1c, 0xc7, 0x80, 0x47, 0x15, 0xfb, 0x47, 0xff,
+      0x72, 0xb1, 0x28, 0x37, 0xb0, 0x4d, 0x6e, 0x22, 0x2e, 0x4d
+  };
 
   uint8_t output1[crypto::kSHA256Length];
   uint8_t output2[crypto::kSHA256Length];
+  uint8_t output3[crypto::kSHA256Length];
 
   scoped_ptr<crypto::SecureHash> ctx1(crypto::SecureHash::Create(
       crypto::SecureHash::SHA256));
-  scoped_ptr<crypto::SecureHash> ctx2(crypto::SecureHash::Create(
-      crypto::SecureHash::SHA256));
-  base::Pickle pickle;
   ctx1->Update(input1.data(), input1.size());
+
+  scoped_ptr<crypto::SecureHash> ctx2(ctx1->Clone());
+  scoped_ptr<crypto::SecureHash> ctx3(ctx2->Clone());
+  // At this point, ctx1, ctx2, and ctx3 are all equivalent and represent the
+  // state after hashing input1.
+
+  // Updating ctx1 and ctx2 with input2 should produce equivalent results.
   ctx1->Update(input2.data(), input2.size());
-  ctx1->Update(input3.data(), input3.size());
-
-  EXPECT_TRUE(ctx1->Serialize(&pickle));
-  ctx1->Update(input4.data(), input4.size());
-  ctx1->Update(input5.data(), input5.size());
-
   ctx1->Finish(output1, sizeof(output1));
 
-  base::PickleIterator data_iterator(pickle);
-  EXPECT_TRUE(ctx2->Deserialize(&data_iterator));
-  ctx2->Update(input4.data(), input4.size());
-  ctx2->Update(input5.data(), input5.size());
-
+  ctx2->Update(input2.data(), input2.size());
   ctx2->Finish(output2, sizeof(output2));
 
   EXPECT_EQ(0, memcmp(output1, output2, crypto::kSHA256Length));
+  EXPECT_EQ(0, memcmp(output1, expected_sha256_hash_of_inputs1and2,
+                      crypto::kSHA256Length));
+
+  // Finish() ctx3, which should produce the hash of input1.
+  ctx3->Finish(&output3, sizeof(output3));
+  EXPECT_EQ(0, memcmp(output3, expected_sha256_hash_of_input1,
+                      crypto::kSHA256Length));
 }
+
+TEST(SecureHashTest, TestLength) {
+  scoped_ptr<crypto::SecureHash> ctx(
+      crypto::SecureHash::Create(crypto::SecureHash::SHA256));
+  EXPECT_EQ(crypto::kSHA256Length, ctx->GetHashLength());
+}