Add FdFile::Compare
Also added unit test. Will be used in tests.
Bug: 63467744
Test: test-art-host-gtest-fd_file_test -j40
(cherry picked from commit 27d680adac56af90906970bfddb404bbb4342ee4)
Change-Id: I5fbfa467e5f3591eadd78905fd5aee7a7712c0b8
diff --git a/runtime/base/unix_file/fd_file.cc b/runtime/base/unix_file/fd_file.cc
index 00b5567..20e0cfa 100644
--- a/runtime/base/unix_file/fd_file.cc
+++ b/runtime/base/unix_file/fd_file.cc
@@ -437,4 +437,30 @@
return true;
}
+int FdFile::Compare(FdFile* other) {
+ int64_t length = GetLength();
+ int64_t length2 = other->GetLength();
+ if (length != length2) {
+ return length < length2 ? -1 : 1;
+ }
+ static const size_t kBufferSize = 4096;
+ std::unique_ptr<uint8_t[]> buffer1(new uint8_t[kBufferSize]);
+ std::unique_ptr<uint8_t[]> buffer2(new uint8_t[kBufferSize]);
+ while (length > 0) {
+ size_t len = std::min(kBufferSize, static_cast<size_t>(length));
+ if (!ReadFully(&buffer1[0], len)) {
+ return -1;
+ }
+ if (!other->ReadFully(&buffer2[0], len)) {
+ return 1;
+ }
+ int result = memcmp(&buffer1[0], &buffer2[0], len);
+ if (result != 0) {
+ return result;
+ }
+ length -= len;
+ }
+ return 0;
+}
+
} // namespace unix_file
diff --git a/runtime/base/unix_file/fd_file.h b/runtime/base/unix_file/fd_file.h
index eb85c4f..7db077d 100644
--- a/runtime/base/unix_file/fd_file.h
+++ b/runtime/base/unix_file/fd_file.h
@@ -145,6 +145,11 @@
// WARNING: Only use this when you know what you're doing!
void MarkUnchecked();
+ // Compare against another file. Returns 0 if the files are equivalent, otherwise returns -1 or 1
+ // depending on if the lenghts are different. If the lengths are the same, the function returns a
+ // value representing which is file is greater (if they are different).
+ int Compare(FdFile* other);
+
protected:
// If the guard state indicates checking (!=kNoCheck), go to the target state "target". Print the
// given warning if the current state is or exceeds warn_threshold.
diff --git a/runtime/base/unix_file/fd_file_test.cc b/runtime/base/unix_file/fd_file_test.cc
index 6aef348..8b1a115 100644
--- a/runtime/base/unix_file/fd_file_test.cc
+++ b/runtime/base/unix_file/fd_file_test.cc
@@ -220,4 +220,58 @@
EXPECT_FALSE(art::OS::FileExists(filename.c_str())) << filename;
}
+TEST_F(FdFileTest, Compare) {
+ std::vector<uint8_t> buffer;
+ constexpr int64_t length = 17 * art::KB;
+ for (size_t i = 0; i < length; ++i) {
+ buffer.push_back(static_cast<uint8_t>(i));
+ }
+
+ auto reset_compare = [&](art::ScratchFile& a, art::ScratchFile& b) {
+ a.GetFile()->ResetOffset();
+ b.GetFile()->ResetOffset();
+ return a.GetFile()->Compare(b.GetFile());
+ };
+
+ art::ScratchFile tmp;
+ EXPECT_TRUE(tmp.GetFile()->WriteFully(&buffer[0], length));
+ EXPECT_EQ(tmp.GetFile()->GetLength(), length);
+
+ art::ScratchFile tmp2;
+ EXPECT_TRUE(tmp2.GetFile()->WriteFully(&buffer[0], length));
+ EXPECT_EQ(tmp2.GetFile()->GetLength(), length);
+
+ // Basic equality check.
+ tmp.GetFile()->ResetOffset();
+ tmp2.GetFile()->ResetOffset();
+ // Files should be the same.
+ EXPECT_EQ(reset_compare(tmp, tmp2), 0);
+
+ // Change a byte near the start.
+ ++buffer[2];
+ art::ScratchFile tmp3;
+ EXPECT_TRUE(tmp3.GetFile()->WriteFully(&buffer[0], length));
+ --buffer[2];
+ EXPECT_NE(reset_compare(tmp, tmp3), 0);
+
+ // Change a byte near the middle.
+ ++buffer[length / 2];
+ art::ScratchFile tmp4;
+ EXPECT_TRUE(tmp4.GetFile()->WriteFully(&buffer[0], length));
+ --buffer[length / 2];
+ EXPECT_NE(reset_compare(tmp, tmp4), 0);
+
+ // Change a byte near the end.
+ ++buffer[length - 5];
+ art::ScratchFile tmp5;
+ EXPECT_TRUE(tmp5.GetFile()->WriteFully(&buffer[0], length));
+ --buffer[length - 5];
+ EXPECT_NE(reset_compare(tmp, tmp5), 0);
+
+ // Reference check
+ art::ScratchFile tmp6;
+ EXPECT_TRUE(tmp6.GetFile()->WriteFully(&buffer[0], length));
+ EXPECT_EQ(reset_compare(tmp, tmp6), 0);
+}
+
} // namespace unix_file
