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[libcxx] Implement parsing of root_name for paths on windows 

Differential Revision: https://reviews.llvm.org/D91176
This commit is contained in:
Martin Storsjö 2020-11-03 23:52:32 +02:00
parent 8ddfcec91b
commit 929f0bcc24
1 changed files with 85 additions and 7 deletions
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92
libcxx/src/filesystem/operations.cpp
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@ -64,6 +64,10 @@ bool isSeparator(path::value_type C) {
return false;
}
bool isDriveLetter(path::value_type C) {
return (C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z');
}
namespace parser {
using string_view_t = path::__string_view;
@ -120,6 +124,12 @@ public:
switch (State) {
case PS_BeforeBegin: {
PosPtr TkEnd = consumeRootName(Start, End);
if (TkEnd)
return makeState(PS_InRootName, Start, TkEnd);
}
_LIBCPP_FALLTHROUGH();
case PS_InRootName: {
PosPtr TkEnd = consumeSeparator(Start, End);
if (TkEnd)
return makeState(PS_InRootDir, Start, TkEnd);
@ -142,7 +152,6 @@ public:
case PS_InTrailingSep:
return makeState(PS_AtEnd);
case PS_InRootName:
case PS_AtEnd:
_LIBCPP_UNREACHABLE();
}
@ -160,9 +169,15 @@ public:
if (PosPtr SepEnd = consumeSeparator(RStart, REnd)) {
if (SepEnd == REnd)
return makeState(PS_InRootDir, Path.data(), RStart + 1);
PosPtr TkStart = consumeRootName(SepEnd, REnd);
if (TkStart == REnd)
return makeState(PS_InRootDir, RStart, RStart + 1);
return makeState(PS_InTrailingSep, SepEnd + 1, RStart + 1);
} else {
PosPtr TkStart = consumeName(RStart, REnd);
PosPtr TkStart = consumeRootName(RStart, REnd);
if (TkStart == REnd)
return makeState(PS_InRootName, TkStart + 1, RStart + 1);
TkStart = consumeName(RStart, REnd);
return makeState(PS_InFilenames, TkStart + 1, RStart + 1);
}
}
@ -173,11 +188,17 @@ public:
PosPtr SepEnd = consumeSeparator(RStart, REnd);
if (SepEnd == REnd)
return makeState(PS_InRootDir, Path.data(), RStart + 1);
PosPtr TkEnd = consumeName(SepEnd, REnd);
return makeState(PS_InFilenames, TkEnd + 1, SepEnd + 1);
PosPtr TkStart = consumeRootName(SepEnd ? SepEnd : RStart, REnd);
if (TkStart == REnd) {
if (SepEnd)
return makeState(PS_InRootDir, SepEnd + 1, RStart + 1);
return makeState(PS_InRootName, TkStart + 1, RStart + 1);
}
TkStart = consumeName(SepEnd, REnd);
return makeState(PS_InFilenames, TkStart + 1, SepEnd + 1);
}
case PS_InRootDir:
// return makeState(PS_InRootName, Path.data(), RStart + 1);
return makeState(PS_InRootName, Path.data(), RStart + 1);
case PS_InRootName:
case PS_BeforeBegin:
_LIBCPP_UNREACHABLE();
@ -284,7 +305,7 @@ private:
}
PosPtr consumeSeparator(PosPtr P, PosPtr End) const noexcept {
if (P == End || !isSeparator(*P))
if (P == nullptr || P == End || !isSeparator(*P))
return nullptr;
const int Inc = P < End ? 1 : -1;
P += Inc;
@ -293,15 +314,72 @@ private:
return P;
}
// Consume exactly N separators, or return nullptr.
PosPtr consumeNSeparators(PosPtr P, PosPtr End, int N) const noexcept {
PosPtr Ret = consumeSeparator(P, End);
if (Ret == nullptr)
return nullptr;
if (P < End) {
if (Ret == P + N)
return Ret;
} else {
if (Ret == P - N)
return Ret;
}
return nullptr;
}
PosPtr consumeName(PosPtr P, PosPtr End) const noexcept {
if (P == End || isSeparator(*P))
PosPtr Start = P;
if (P == nullptr || P == End || isSeparator(*P))
return nullptr;
const int Inc = P < End ? 1 : -1;
P += Inc;
while (P != End && !isSeparator(*P))
P += Inc;
if (P == End && Inc < 0) {
// Iterating backwards and consumed all the rest of the input.
// Check if the start of the string would have been considered
// a root name.
PosPtr RootEnd = consumeRootName(End + 1, Start);
if (RootEnd)
return RootEnd - 1;
}
return P;
}
PosPtr consumeDriveLetter(PosPtr P, PosPtr End) const noexcept {
if (P == End)
return nullptr;
if (P < End) {
if (P + 1 == End || !isDriveLetter(P[0]) || P[1] != ':')
return nullptr;
return P + 2;
} else {
if (P - 1 == End || !isDriveLetter(P[-1]) || P[0] != ':')
return nullptr;
return P - 2;
}
}
PosPtr consumeNetworkRoot(PosPtr P, PosPtr End) const noexcept {
if (P == End)
return nullptr;
if (P < End)
return consumeName(consumeNSeparators(P, End, 2), End);
else
return consumeNSeparators(consumeName(P, End), End, 2);
}
PosPtr consumeRootName(PosPtr P, PosPtr End) const noexcept {
#if defined(_LIBCPP_WIN32API)
if (PosPtr Ret = consumeDriveLetter(P, End))
return Ret;
if (PosPtr Ret = consumeNetworkRoot(P, End))
return Ret;
#endif
return nullptr;
}
};
string_view_pair separate_filename(string_view_t const& s) {