[libcxx] r349881 - Implement LWG 2936: Path comparison is defined in terms of the generic format
Eric Fiselier
eric at efcs.ca
Thu Dec 20 19:16:30 PST 2018
Author: ericwf
Date: Thu Dec 20 19:16:30 2018
New Revision: 349881
URL: http://llvm.org/viewvc/llvm-project?rev=349881&view=rev
Log:
Implement LWG 2936: Path comparison is defined in terms of the generic format
This patch implements path::compare according to the current spec. The
only observable change is the ordering of "/foo" and "foo", which orders
the two paths based on having or not having a root directory (instead
of lexically comparing "/" to "foo").
Modified:
libcxx/trunk/src/filesystem/operations.cpp
libcxx/trunk/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp
libcxx/trunk/www/cxx2a_status.html
Modified: libcxx/trunk/src/filesystem/operations.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/filesystem/operations.cpp?rev=349881&r1=349880&r2=349881&view=diff
==============================================================================
--- libcxx/trunk/src/filesystem/operations.cpp (original)
+++ libcxx/trunk/src/filesystem/operations.cpp Thu Dec 20 19:16:30 2018
@@ -206,8 +206,20 @@ public:
return *this;
}
+ bool atEnd() const noexcept {
+ return State == PS_AtEnd;
+ }
+
+ bool inRootDir() const noexcept {
+ return State == PS_InRootDir;
+ }
+
+ bool inRootName() const noexcept {
+ return State == PS_InRootName;
+ }
+
bool inRootPath() const noexcept {
- return State == PS_InRootDir || State == PS_InRootName;
+ return inRootName() || inRootDir();
}
private:
@@ -1294,7 +1306,19 @@ string_view_t path::__root_path_raw() co
return {};
}
+static bool ConsumeRootName(PathParser *PP) {
+ static_assert(PathParser::PS_BeforeBegin == 1 &&
+ PathParser::PS_InRootName == 2,
+ "Values for enums are incorrect");
+ while (PP->State <= PathParser::PS_InRootName)
+ ++(*PP);
+ return PP->State == PathParser::PS_AtEnd;
+}
+
static bool ConsumeRootDir(PathParser* PP) {
+ static_assert(PathParser::PS_BeforeBegin == 1 &&
+ PathParser::PS_InRootName == 2 &&
+ PathParser::PS_InRootDir == 3, "Values for enums are incorrect");
while (PP->State <= PathParser::PS_InRootDir)
++(*PP);
return PP->State == PathParser::PS_AtEnd;
@@ -1514,21 +1538,68 @@ path path::lexically_relative(const path
////////////////////////////////////////////////////////////////////////////
// path.comparisons
-int path::__compare(string_view_t __s) const {
- auto PP = PathParser::CreateBegin(__pn_);
- auto PP2 = PathParser::CreateBegin(__s);
- while (PP && PP2) {
- int res = (*PP).compare(*PP2);
- if (res != 0)
+static int CompareRootName(PathParser *LHS, PathParser *RHS) {
+ if (!LHS->inRootName() && !RHS->inRootName())
+ return 0;
+
+ auto GetRootName = [](PathParser *Parser) -> string_view_t {
+ return Parser->inRootName() ? **Parser : "";
+ };
+ int res = GetRootName(LHS).compare(GetRootName(RHS));
+ ConsumeRootName(LHS);
+ ConsumeRootName(RHS);
+ return res;
+}
+
+static int CompareRootDir(PathParser *LHS, PathParser *RHS) {
+ if (!LHS->inRootDir() && RHS->inRootDir())
+ return -1;
+ else if (LHS->inRootDir() && !RHS->inRootDir())
+ return 1;
+ else {
+ ConsumeRootDir(LHS);
+ ConsumeRootDir(RHS);
+ return 0;
+ }
+}
+
+static int CompareRelative(PathParser *LHSPtr, PathParser *RHSPtr) {
+ auto &LHS = *LHSPtr;
+ auto &RHS = *RHSPtr;
+
+ int res;
+ while (LHS && RHS) {
+ if ((res = (*LHS).compare(*RHS)) != 0)
return res;
- ++PP;
- ++PP2;
+ ++LHS;
+ ++RHS;
}
- if (PP.State == PP2.State && !PP)
- return 0;
- if (!PP)
+ return 0;
+}
+
+static int CompareEndState(PathParser *LHS, PathParser *RHS) {
+ if (LHS->atEnd() && !RHS->atEnd())
return -1;
- return 1;
+ else if (!LHS->atEnd() && RHS->atEnd())
+ return 1;
+ return 0;
+}
+
+int path::__compare(string_view_t __s) const {
+ auto LHS = PathParser::CreateBegin(__pn_);
+ auto RHS = PathParser::CreateBegin(__s);
+ int res;
+
+ if ((res = CompareRootName(&LHS, &RHS)) != 0)
+ return res;
+
+ if ((res = CompareRootDir(&LHS, &RHS)) != 0)
+ return res;
+
+ if ((res = CompareRelative(&LHS, &RHS)) != 0)
+ return res;
+
+ return CompareEndState(&LHS, &RHS);
}
////////////////////////////////////////////////////////////////////////////
Modified: libcxx/trunk/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp?rev=349881&r1=349880&r2=349881&view=diff
==============================================================================
--- libcxx/trunk/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp (original)
+++ libcxx/trunk/test/std/input.output/filesystems/class.path/path.member/path.compare.pass.cpp Thu Dec 20 19:16:30 2018
@@ -65,6 +65,8 @@ const PathCompareTest CompareTestCases[]
{"//foo//bar///baz////", "//foo/bar/baz/", 0}, // duplicate separators
{"///foo/bar", "/foo/bar", 0}, // "///" is not a root directory
{"/foo/bar/", "/foo/bar", 1}, // trailing separator
+ {"foo", "/foo", -1}, // if !this->has_root_directory() and p.has_root_directory(), a value less than 0.
+ {"/foo", "foo", 1}, // if this->has_root_directory() and !p.has_root_directory(), a value greater than 0.
{"//" LONGA "////" LONGB "/" LONGC "///" LONGD, "//" LONGA "/" LONGB "/" LONGC "/" LONGD, 0},
{ LONGA "/" LONGB "/" LONGC, LONGA "/" LONGB "/" LONGB, 1}
@@ -79,7 +81,7 @@ static inline int normalize_ret(int ret)
return ret < 0 ? -1 : (ret > 0 ? 1 : 0);
}
-int main()
+void test_compare_basic()
{
using namespace fs;
for (auto const & TC : CompareTestCases) {
@@ -136,3 +138,54 @@ int main()
}
}
}
+
+int CompareElements(std::vector<std::string> const& LHS, std::vector<std::string> const& RHS) {
+ bool IsLess = std::lexicographical_compare(LHS.begin(), LHS.end(), RHS.begin(), RHS.end());
+ if (IsLess)
+ return -1;
+
+ bool IsGreater = std::lexicographical_compare(RHS.begin(), RHS.end(), LHS.begin(), LHS.end());
+ if (IsGreater)
+ return 1;
+
+ return 0;
+}
+
+void test_compare_elements() {
+ struct {
+ std::vector<std::string> LHSElements;
+ std::vector<std::string> RHSElements;
+ int Expect;
+ } TestCases[] = {
+ {{"a"}, {"a"}, 0},
+ {{"a"}, {"b"}, -1},
+ {{"b"}, {"a"}, 1},
+ {{"a", "b", "c"}, {"a", "b", "c"}, 0},
+ {{"a", "b", "c"}, {"a", "b", "d"}, -1},
+ {{"a", "b", "d"}, {"a", "b", "c"}, 1},
+ {{"a", "b"}, {"a", "b", "c"}, -1},
+ {{"a", "b", "c"}, {"a", "b"}, 1},
+
+ };
+
+ auto BuildPath = [](std::vector<std::string> const& Elems) {
+ fs::path p;
+ for (auto &E : Elems)
+ p /= E;
+ return p;
+ };
+
+ for (auto &TC : TestCases) {
+ fs::path LHS = BuildPath(TC.LHSElements);
+ fs::path RHS = BuildPath(TC.RHSElements);
+ const int ExpectCmp = CompareElements(TC.LHSElements, TC.RHSElements);
+ assert(ExpectCmp == TC.Expect);
+ const int GotCmp = normalize_ret(LHS.compare(RHS));
+ assert(GotCmp == TC.Expect);
+ }
+}
+
+int main() {
+ test_compare_basic();
+ test_compare_elements();
+}
Modified: libcxx/trunk/www/cxx2a_status.html
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/www/cxx2a_status.html?rev=349881&r1=349880&r2=349881&view=diff
==============================================================================
--- libcxx/trunk/www/cxx2a_status.html (original)
+++ libcxx/trunk/www/cxx2a_status.html Thu Dec 20 19:16:30 2018
@@ -258,7 +258,7 @@
<tr><td><a href="https://wg21.link/LWG2682">2682</a></td><td><code>filesystem::copy()</code> won't create a symlink to a directory</td><td>San Diego</td><td>Nothing to do</td></tr>
<tr><td><a href="https://wg21.link/LWG2697">2697</a></td><td>[concurr.ts] Behavior of <tt>future/shared_future</tt> unwrapping constructor when given an invalid <tt>future</tt></td><td>San Diego</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG2797">2797</a></td><td>Trait precondition violations</td><td>San Diego</td><td>Resolved by 1285R0</td></tr>
- <tr><td><a href="https://wg21.link/LWG2936">2936</a></td><td>Path comparison is defined in terms of the generic format</td><td>San Diego</td><td></td></tr>
+ <tr><td><a href="https://wg21.link/LWG2936">2936</a></td><td>Path comparison is defined in terms of the generic format</td><td>San Diego</td><td>Complete</td></tr>
<tr><td><a href="https://wg21.link/LWG2943">2943</a></td><td>Problematic specification of the wide version of <tt>basic_filebuf::open</tt></td><td>San Diego</td><td>Nothing to do</td></tr>
<tr><td><a href="https://wg21.link/LWG2960">2960</a></td><td>[fund.ts.v3] <tt>nonesuch</tt> is insufficiently useless</td><td>San Diego</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG2995">2995</a></td><td><tt>basic_stringbuf</tt> default constructor forbids it from using SSO capacity</td><td>San Diego</td><td></td></tr>
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