[PATCH] D69958: Improve VFS compatibility on Windows

Wed Nov 13 11:25:05 PST 2019

amccarth marked 3 inline comments as done.
amccarth added a comment.

Friendly ping for any VFS experts to comment.

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Comment at: llvm/include/llvm/Support/VirtualFileSystem.h:657
+  // slashes to match backslashes (and vice versa).
+  bool pathComponentMatches(llvm::StringRef lhs, llvm::StringRef rhs) const {
+    if ((CaseSensitive ? lhs.equals(rhs) : lhs.equals_lower(rhs)))
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rnk wrote:
> IIUC, this method receives path components, which must not contain path separators, or the root path component, `\` or `/`. Is there some way to express that invariant? Maybe just comment like "A path component must not contain path separators, unless it is the root component, which is represented as a single path separator," or an assert with the same effect.
I felt the assumption is implicit in "path component," but I've made the comment more explicit.  Note that the slash/backslash checks are checking the entire string.  I hope that reinforces the idea that these would be path roots.

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Comment at: llvm/lib/Support/VirtualFileSystem.cpp:1666
   // paths become globally default.
   if (Start->equals("."))
     ++Start;
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rnk wrote:
> Unrelated, but I wonder if this needs to be `while` instead of `if` to handle repeated `foo/./././bar`.
I'm fairly certain I'll be looking into this further as I try to resolve the remaining VFS tests that don't run on Windows.  I'd love to eliminate another #ifdef, but I want to keep this patch focused.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D69958/new/

https://reviews.llvm.org/D69958