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author | Aaron Ballman <aaron@aaronballman.com> | 2013-06-19 21:03:50 +0000 |
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committer | Aaron Ballman <aaron@aaronballman.com> | 2013-06-19 21:03:50 +0000 |
commit | 4655485eb7dc1d137595149b9bd58eb73e11bb19 (patch) | |
tree | 491409b3cdc3810bc088ef129469167e7c999d01 /lib | |
parent | 7032c883cdf8da579fbf9bf499d36a711eef676f (diff) | |
download | llvm-4655485eb7dc1d137595149b9bd58eb73e11bb19.tar.gz llvm-4655485eb7dc1d137595149b9bd58eb73e11bb19.tar.bz2 llvm-4655485eb7dc1d137595149b9bd58eb73e11bb19.tar.xz |
Modified the implementation of fs::GetUniqueID on Windows such that it actually finds a unique identifier for a file. Also adds unit tests for GetUniqueID.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184351 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Support/Windows/PathV2.inc | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/lib/Support/Windows/PathV2.inc b/lib/Support/Windows/PathV2.inc index bec95e36cc..e6888f93e6 100644 --- a/lib/Support/Windows/PathV2.inc +++ b/lib/Support/Windows/PathV2.inc @@ -426,15 +426,20 @@ error_code file_size(const Twine &path, uint64_t &result) { } error_code GetUniqueID(const Twine Path, uint64_t &Result) { - // FIXME: this is only unique if the file is accessed by the same file path. - // How do we do this for C:\dir\file and ..\dir\file ? Unix has inode - // numbers, but the concept doesn't exist in Windows. - SmallString<128> Storage; - StringRef P = Path.toStringRef(Storage); - uint64_t UniqueID = 0; - for (StringRef::iterator I = P.begin(), E = P.end(); I != E; ++I) - UniqueID += *I; - Result = UniqueID; + file_status Status; + if (error_code E = status(Path, Status)) + return E; + + // The file is uniquely identified by the volume serial number along + // with the 64-bit file identifier. + Result = (static_cast<uint64_t>(Status.FileIndexHigh) << 32ULL) | + static_cast<uint64_t>(Status.FileIndexLow); + + // Because the serial number is 32-bits, but we've already used up all 64 + // bits for the file index, XOR the serial number into the high 32 bits of + // the resulting value. We could potentially get collisons from this, but + // the likelihood is low. + Result ^= (static_cast<uint64_t>(Status.VolumeSerialNumber) << 32ULL); return error_code::success(); } |