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Canonicalize path names in the file manager before performing a lookup 

on that name. Canonicalization eliminates silliness such as "." and
"foo/.." that breaks the uniquing of files in the presence of virtual
files or files whose inode numbers have changed during
parsing/re-parsing. c-index-test isn't able to create this crazy
situation, so I've resorted to testing outside of the Clang
tree. Fixes <rdar://problem/8928220>.

Note that this hackery will go away once we have a real virtual file
system on which we can layer FileManager; the virtual-files hack is
showing cracks.

llvm-svn: 124754
This commit is contained in:
Douglas Gregor 2011-02-02 22:30:17 +00:00
parent e3773c2f51
commit 3c0d263abb
1 changed files with 77 additions and 0 deletions
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77
clang/lib/Basic/FileManager.cpp
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@ -271,10 +271,84 @@ const DirectoryEntry *FileManager::getDirectory(llvm::StringRef Filename) {
return &UDE;
}
/// \brief Canonicalize a file or path name by eliminating redundant
/// "foo/.." and "./" path components.
///
/// Uses the given scratch space to store the resulting string, if needed.
static llvm::StringRef CanonicalizeFileName(llvm::StringRef Filename,
llvm::SmallVectorImpl<char> &Scratch) {
size_t Start = 0;
bool Changed = false;
do {
size_t FirstSlash = Filename.find('/', Start);
if (FirstSlash == llvm::StringRef::npos) {
// No more components. Just copy the rest of the file name, if
// we need to.
if (Changed)
Scratch.append(Filename.begin() + Start, Filename.end());
break;
}
if (Start + 1 == FirstSlash && Filename[Start] == '.') {
// We have './'; remove it.
// If we haven't changed anything previously, copy the
// starting bits here.
if (!Changed) {
Scratch.clear();
Scratch.append(Filename.begin(), Filename.begin() + Start);
Changed = true;
}
// Skip over the './'.
Start = FirstSlash + 1;
continue;
}
size_t SecondSlash = Filename.find('/', FirstSlash + 1);
if (SecondSlash != llvm::StringRef::npos &&
SecondSlash - FirstSlash == 3 &&
Filename[FirstSlash + 1] == '.' &&
Filename[FirstSlash + 2] == '.') {
// We have 'foo/../'; remove it.
// If we haven't changed anything previously, copy the
// starting bits here.
if (!Changed) {
Scratch.clear();
Scratch.append(Filename.begin(), Filename.begin() + Start);
Changed = true;
}
// Skip over the 'foo/..'.
Start = SecondSlash + 1;
continue;
}
if (Changed)
Scratch.append(Filename.begin() + Start,
Filename.begin() + FirstSlash + 1);
Start = FirstSlash + 1;
} while (true);
if (Changed) {
#if 0
llvm::errs() << "Canonicalized \"" << Filename << "\" to \""
<< llvm::StringRef(Scratch.data(), Scratch.size()) << "\"\n";
#endif
return llvm::StringRef(Scratch.data(), Scratch.size());
}
return Filename;
}
/// getFile - Lookup, cache, and verify the specified file. This returns null
/// if the file doesn't exist.
///
const FileEntry *FileManager::getFile(llvm::StringRef Filename) {
llvm::SmallString<128> FilenameScratch;
Filename = CanonicalizeFileName(Filename, FilenameScratch);
++NumFileLookups;
// See if there is already an entry in the map.
@ -343,6 +417,9 @@ const FileEntry *FileManager::getFile(llvm::StringRef Filename) {
const FileEntry *
FileManager::getVirtualFile(llvm::StringRef Filename, off_t Size,
time_t ModificationTime) {
llvm::SmallString<128> FilenameScratch;
Filename = CanonicalizeFileName(Filename, FilenameScratch);
++NumFileLookups;
// See if there is already an entry in the map.