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[FOLD] relative
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@alandefreitas
alandefreitas committed Aug 18, 2022
1 parent 3e9269d commit f4d9041
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Showing 2 changed files with 59 additions and 89 deletions.
136 changes: 54 additions & 82 deletions include/boost/url/impl/url.ipp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -156,20 +156,16 @@ relative(
// us slightly different results.
// - The basic exception guarantee is not
// satisfied in case of allocation errors.

BOOST_ASSERT(&dest != &base);
BOOST_ASSERT(&dest != &href);

// Validate input
if (!href.is_path_absolute())
{
// href is already relative
return error::not_a_base;
}
if (!base.is_path_absolute())
if (!href.is_path_absolute() ||
!base.is_path_absolute())
{
// href is already relative or
// cannot calculate a URI relative to another relative URI
return error::not_a_base;
BOOST_URL_RETURN_EC(error::not_a_base);
}

// Resolve scheme
Expand Down Expand Up @@ -209,16 +205,45 @@ relative(
// 0. Get segments
auto segs0 = base.segments();
auto segs1 = href.segments();
auto begin0 = segs0.begin();

// Reference iterators
auto const begin0 = segs0.begin();
auto it0 = begin0;
auto end0 = segs0.end();
auto last0 = begin0 != end0 ? std::prev(end0) : end0;
auto begin1 = segs1.begin();
auto const end0 = segs0.end();
auto const last0 = begin0 != end0 ? std::prev(end0) : end0;
auto const begin1 = segs1.begin();
auto it1 = begin1;
auto end1 = segs1.end();
auto last1 = begin0 != end1 ? std::prev(end1) : end1;
pct_encoded_view const dotdot("..");
pct_encoded_view const dot(".");
auto const end1 = segs1.end();
auto const last1 = begin0 != end1 ? std::prev(end1) : end1;

// Function to advance the dotdot segments
pct_encoded_view dotdot("..");
pct_encoded_view dot(".");
auto consume_dots = [dotdot, dot](
segments_view::iterator& first,
segments_view::iterator last)
{
auto it = std::next(first);
std::size_t l = 1;
while (it != last)
{
if (*it == dotdot)
{
if (--l == 0)
{
++it;
first = it;
break;
}
}
else if (*it != dot)
{
++l;
}
++it;
}
return first == it;
};

// 1. Find the longest common path
while (
Expand Down Expand Up @@ -252,65 +277,23 @@ relative(
}
else
{
// Check if *it0 will be consumed by a dotdot
auto it2 = std::next(it0);
std::size_t l = 1;
while (it2 != last0)
{
if (*it2 == dotdot)
{
if (--l == 0)
{
++it2;
it0 = it2;
break;
}
}
else if (*it2 != dot)
{
++l;
}
++it2;
}
if (it0 == it2)
if (consume_dots(it0, last0))
continue;

// Check if *it1 will be consumed by a dotdot
auto it3 = std::next(it1);
l = 1;
while (it3 != last1)
{
if (*it3 == dotdot)
{
if (--l == 0)
{
++it3;
it1 = it3;
break;
}
}
else if (*it3 != dot)
{
++l;
}
++it3;
}
if (it1 == it3)
if (consume_dots(it1, last1))
continue;

break;
}
}

// 1.b Check if paths are the same
// 1.b Check if parent paths are the same
if (it0 == last0 &&
it1 == last1 &&
it0 != end0 &&
it1 != end1 &&
*it0 == *it1)
{
// Return empty path
dest.segments() = {dot.encoded()};
dest.segments() = {};
if (href.has_query())
dest.set_encoded_query(href.encoded_query());
else
Expand All @@ -322,54 +305,43 @@ relative(
return {};
}

// 2. replace each path component in the
// base path with ../
// 2. Append ".." for each segment left in base
segments_encoded segs = dest.encoded_segments();
segs = {dot.encoded()};
segs = {};
if (it0 != end0)
{
dest.set_path_absolute(false);
auto last0 = std::prev(end0);
while (it0 != last0)
{
if (*it0 == dotdot)
{
if (segs.size() > 1)
if (!segs.empty())
segs.pop_back();
else
segs = {dot.encoded()};
}
else if (*it0 != dot)
{
if (dest.path() == dot)
segs = {dotdot.encoded()};
else
segs.push_back(dotdot.encoded());
segs.push_back(dotdot.encoded());
}
++it0;
}
}

// 3. Append the reference path
// 3. Append segments left from the reference
while (it1 != end1)
{
if (*it1 == dotdot)
{
if (segs.size() > 1)
if (!segs.empty())
segs.pop_back();
else
segs = {dot.encoded()};
}
else if (*it1 != dot)
{
string_view v = (*it1).encoded();
if (dest.path() == dot)
segs = {v};
else
segs.push_back(v);
segs.push_back((*it1).encoded());
}
++it1;
}

// Query and fragment comes from reference
if (href.has_query())
dest.set_encoded_query(href.encoded_query());
else
Expand Down
12 changes: 5 additions & 7 deletions test/unit/url.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2089,10 +2089,8 @@ class url_test
check("/relative/sub/foo/sub/file", "/relative/path", "../../../path");
check("http://google.com/baz", "http://example.org/world.html", "//example.org/world.html");
check("http://google.com/baz", "http:/world.html", "/world.html");
// AFREITAS: The paths below should be "" but set_path("") and segments() = {} crash
// "." is still equivalent
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file", ".");
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file?foo=bar#abcd", ".?foo=bar#abcd");
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file", "");
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file?foo=bar#abcd", "?foo=bar#abcd");
// "." should be ignored
check("/a/path/././to/./somewhere/else", "/a/./path/./to/a", "../a");
// ".." should be normalized
Expand Down Expand Up @@ -2142,11 +2140,11 @@ class url_test
// different port 3
check("http://example.org/foo/bar", "http://example.org:8081/foo/bar", "//example.org:8081/foo/bar");
// same path - fragment
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file#abcd", ".#abcd");
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file#abcd", "#abcd");
// same path - query
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file?abcd=123", ".?abcd=123");
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file?abcd=123", "?abcd=123");
// same path - query and fragment
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file?abcd=123#alpha", ".?abcd=123#alpha");
check("http://www.example.com:8080/dir/file", "http://www.example.com:8080/dir/file?abcd=123#alpha", "?abcd=123#alpha");

auto const fail = [](
string_view b,
Expand Down

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