Merge pull request #7450 from edolstra/canon-path
Add CanonPath wrapper to represent canonicalized paths
This commit is contained in:
Eelco Dolstra
GitHub
commit
d00bfe4833
3 changed files with 431 additions and 0 deletions
103
src/libutil/canon-path.cc
Normal file
103
src/libutil/canon-path.cc
Normal file
|
|
@ -0,0 +1,103 @@
|
|||
#include "canon-path.hh"
|
||||
#include "util.hh"
|
||||
|
||||
namespace nix {
|
||||
|
||||
CanonPath CanonPath::root = CanonPath("/");
|
||||
|
||||
CanonPath::CanonPath(std::string_view raw)
|
||||
: path(absPath((Path) raw, "/"))
|
||||
{ }
|
||||
|
||||
CanonPath::CanonPath(std::string_view raw, const CanonPath & root)
|
||||
: path(absPath((Path) raw, root.abs()))
|
||||
{ }
|
||||
|
||||
std::optional<CanonPath> CanonPath::parent() const
|
||||
{
|
||||
if (isRoot()) return std::nullopt;
|
||||
return CanonPath(unchecked_t(), path.substr(0, std::max((size_t) 1, path.rfind('/'))));
|
||||
}
|
||||
|
||||
void CanonPath::pop()
|
||||
{
|
||||
assert(!isRoot());
|
||||
path.resize(std::max((size_t) 1, path.rfind('/')));
|
||||
}
|
||||
|
||||
bool CanonPath::isWithin(const CanonPath & parent) const
|
||||
{
|
||||
return !(
|
||||
path.size() < parent.path.size()
|
||||
|| path.substr(0, parent.path.size()) != parent.path
|
||||
|| (parent.path.size() > 1 && path.size() > parent.path.size()
|
||||
&& path[parent.path.size()] != '/'));
|
||||
}
|
||||
|
||||
CanonPath CanonPath::removePrefix(const CanonPath & prefix) const
|
||||
{
|
||||
assert(isWithin(prefix));
|
||||
if (prefix.isRoot()) return *this;
|
||||
if (path.size() == prefix.path.size()) return root;
|
||||
return CanonPath(unchecked_t(), path.substr(prefix.path.size()));
|
||||
}
|
||||
|
||||
void CanonPath::extend(const CanonPath & x)
|
||||
{
|
||||
if (x.isRoot()) return;
|
||||
if (isRoot())
|
||||
path += x.rel();
|
||||
else
|
||||
path += x.abs();
|
||||
}
|
||||
|
||||
CanonPath CanonPath::operator + (const CanonPath & x) const
|
||||
{
|
||||
auto res = *this;
|
||||
res.extend(x);
|
||||
return res;
|
||||
}
|
||||
|
||||
void CanonPath::push(std::string_view c)
|
||||
{
|
||||
assert(c.find('/') == c.npos);
|
||||
assert(c != "." && c != "..");
|
||||
if (!isRoot()) path += '/';
|
||||
path += c;
|
||||
}
|
||||
|
||||
CanonPath CanonPath::operator + (std::string_view c) const
|
||||
{
|
||||
auto res = *this;
|
||||
res.push(c);
|
||||
return res;
|
||||
}
|
||||
|
||||
bool CanonPath::isAllowed(const std::set<CanonPath> & allowed) const
|
||||
{
|
||||
/* Check if `this` is an exact match or the parent of an
|
||||
allowed path. */
|
||||
auto lb = allowed.lower_bound(*this);
|
||||
if (lb != allowed.end()) {
|
||||
if (lb->isWithin(*this))
|
||||
return true;
|
||||
}
|
||||
|
||||
/* Check if a parent of `this` is allowed. */
|
||||
auto path = *this;
|
||||
while (!path.isRoot()) {
|
||||
path.pop();
|
||||
if (allowed.count(path))
|
||||
return true;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
std::ostream & operator << (std::ostream & stream, const CanonPath & path)
|
||||
{
|
||||
stream << path.abs();
|
||||
return stream;
|
||||
}
|
||||
|
||||
}
|
||||
173
src/libutil/canon-path.hh
Normal file
173
src/libutil/canon-path.hh
Normal file
|
|
@ -0,0 +1,173 @@
|
|||
#pragma once
|
||||
|
||||
#include <string>
|
||||
#include <optional>
|
||||
#include <cassert>
|
||||
#include <iostream>
|
||||
#include <set>
|
||||
|
||||
namespace nix {
|
||||
|
||||
/* A canonical representation of a path. It ensures the following:
|
||||
|
||||
- It always starts with a slash.
|
||||
|
||||
- It never ends with a slash, except if the path is "/".
|
||||
|
||||
- A slash is never followed by a slash (i.e. no empty components).
|
||||
|
||||
- There are no components equal to '.' or '..'.
|
||||
|
||||
Note that the path does not need to correspond to an actually
|
||||
existing path, and there is no guarantee that symlinks are
|
||||
resolved.
|
||||
*/
|
||||
class CanonPath
|
||||
{
|
||||
std::string path;
|
||||
|
||||
public:
|
||||
|
||||
/* Construct a canon path from a non-canonical path. Any '.', '..'
|
||||
or empty components are removed. */
|
||||
CanonPath(std::string_view raw);
|
||||
|
||||
explicit CanonPath(const char * raw)
|
||||
: CanonPath(std::string_view(raw))
|
||||
{ }
|
||||
|
||||
struct unchecked_t { };
|
||||
|
||||
CanonPath(unchecked_t _, std::string path)
|
||||
: path(std::move(path))
|
||||
{ }
|
||||
|
||||
static CanonPath root;
|
||||
|
||||
/* If `raw` starts with a slash, return
|
||||
`CanonPath(raw)`. Otherwise return a `CanonPath` representing
|
||||
`root + "/" + raw`. */
|
||||
CanonPath(std::string_view raw, const CanonPath & root);
|
||||
|
||||
bool isRoot() const
|
||||
{ return path.size() <= 1; }
|
||||
|
||||
explicit operator std::string_view() const
|
||||
{ return path; }
|
||||
|
||||
const std::string & abs() const
|
||||
{ return path; }
|
||||
|
||||
/* Like abs(), but return an empty string if this path is
|
||||
'/'. Thus the returned string never ends in a slash. */
|
||||
const std::string & absOrEmpty() const
|
||||
{
|
||||
const static std::string epsilon;
|
||||
return isRoot() ? epsilon : path;
|
||||
}
|
||||
|
||||
const char * c_str() const
|
||||
{ return path.c_str(); }
|
||||
|
||||
std::string_view rel() const
|
||||
{ return ((std::string_view) path).substr(1); }
|
||||
|
||||
struct Iterator
|
||||
{
|
||||
std::string_view remaining;
|
||||
size_t slash;
|
||||
|
||||
Iterator(std::string_view remaining)
|
||||
: remaining(remaining)
|
||||
, slash(remaining.find('/'))
|
||||
{ }
|
||||
|
||||
bool operator != (const Iterator & x) const
|
||||
{ return remaining.data() != x.remaining.data(); }
|
||||
|
||||
const std::string_view operator * () const
|
||||
{ return remaining.substr(0, slash); }
|
||||
|
||||
void operator ++ ()
|
||||
{
|
||||
if (slash == remaining.npos)
|
||||
remaining = remaining.substr(remaining.size());
|
||||
else {
|
||||
remaining = remaining.substr(slash + 1);
|
||||
slash = remaining.find('/');
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
Iterator begin() const { return Iterator(rel()); }
|
||||
Iterator end() const { return Iterator(rel().substr(path.size() - 1)); }
|
||||
|
||||
std::optional<CanonPath> parent() const;
|
||||
|
||||
/* Remove the last component. Panics if this path is the root. */
|
||||
void pop();
|
||||
|
||||
std::optional<std::string_view> dirOf() const
|
||||
{
|
||||
if (isRoot()) return std::nullopt;
|
||||
return path.substr(0, path.rfind('/'));
|
||||
}
|
||||
|
||||
std::optional<std::string_view> baseName() const
|
||||
{
|
||||
if (isRoot()) return std::nullopt;
|
||||
return ((std::string_view) path).substr(path.rfind('/') + 1);
|
||||
}
|
||||
|
||||
bool operator == (const CanonPath & x) const
|
||||
{ return path == x.path; }
|
||||
|
||||
bool operator != (const CanonPath & x) const
|
||||
{ return path != x.path; }
|
||||
|
||||
/* Compare paths lexicographically except that path separators
|
||||
are sorted before any other character. That is, in the sorted order
|
||||
a directory is always followed directly by its children. For
|
||||
instance, 'foo' < 'foo/bar' < 'foo!'. */
|
||||
bool operator < (const CanonPath & x) const
|
||||
{
|
||||
auto i = path.begin();
|
||||
auto j = x.path.begin();
|
||||
for ( ; i != path.end() && j != x.path.end(); ++i, ++j) {
|
||||
auto c_i = *i;
|
||||
if (c_i == '/') c_i = 0;
|
||||
auto c_j = *j;
|
||||
if (c_j == '/') c_j = 0;
|
||||
if (c_i < c_j) return true;
|
||||
if (c_i > c_j) return false;
|
||||
}
|
||||
return i == path.end() && j != x.path.end();
|
||||
}
|
||||
|
||||
/* Return true if `this` is equal to `parent` or a child of
|
||||
`parent`. */
|
||||
bool isWithin(const CanonPath & parent) const;
|
||||
|
||||
CanonPath removePrefix(const CanonPath & prefix) const;
|
||||
|
||||
/* Append another path to this one. */
|
||||
void extend(const CanonPath & x);
|
||||
|
||||
/* Concatenate two paths. */
|
||||
CanonPath operator + (const CanonPath & x) const;
|
||||
|
||||
/* Add a path component to this one. It must not contain any slashes. */
|
||||
void push(std::string_view c);
|
||||
|
||||
CanonPath operator + (std::string_view c) const;
|
||||
|
||||
/* Check whether access to this path is allowed, which is the case
|
||||
if 1) `this` is within any of the `allowed` paths; or 2) any of
|
||||
the `allowed` paths are within `this`. (The latter condition
|
||||
ensures access to the parents of allowed paths.) */
|
||||
bool isAllowed(const std::set<CanonPath> & allowed) const;
|
||||
};
|
||||
|
||||
std::ostream & operator << (std::ostream & stream, const CanonPath & path);
|
||||
|
||||
}
|
||||
155
src/libutil/tests/canon-path.cc
Normal file
155
src/libutil/tests/canon-path.cc
Normal file
|
|
@ -0,0 +1,155 @@
|
|||
#include "canon-path.hh"
|
||||
|
||||
#include <gtest/gtest.h>
|
||||
|
||||
namespace nix {
|
||||
|
||||
TEST(CanonPath, basic) {
|
||||
{
|
||||
CanonPath p("/");
|
||||
ASSERT_EQ(p.abs(), "/");
|
||||
ASSERT_EQ(p.rel(), "");
|
||||
ASSERT_EQ(p.baseName(), std::nullopt);
|
||||
ASSERT_EQ(p.dirOf(), std::nullopt);
|
||||
ASSERT_FALSE(p.parent());
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p("/foo//");
|
||||
ASSERT_EQ(p.abs(), "/foo");
|
||||
ASSERT_EQ(p.rel(), "foo");
|
||||
ASSERT_EQ(*p.baseName(), "foo");
|
||||
ASSERT_EQ(*p.dirOf(), ""); // FIXME: do we want this?
|
||||
ASSERT_EQ(p.parent()->abs(), "/");
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p("foo/bar");
|
||||
ASSERT_EQ(p.abs(), "/foo/bar");
|
||||
ASSERT_EQ(p.rel(), "foo/bar");
|
||||
ASSERT_EQ(*p.baseName(), "bar");
|
||||
ASSERT_EQ(*p.dirOf(), "/foo");
|
||||
ASSERT_EQ(p.parent()->abs(), "/foo");
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p("foo//bar/");
|
||||
ASSERT_EQ(p.abs(), "/foo/bar");
|
||||
ASSERT_EQ(p.rel(), "foo/bar");
|
||||
ASSERT_EQ(*p.baseName(), "bar");
|
||||
ASSERT_EQ(*p.dirOf(), "/foo");
|
||||
}
|
||||
}
|
||||
|
||||
TEST(CanonPath, pop) {
|
||||
CanonPath p("foo/bar/x");
|
||||
ASSERT_EQ(p.abs(), "/foo/bar/x");
|
||||
p.pop();
|
||||
ASSERT_EQ(p.abs(), "/foo/bar");
|
||||
p.pop();
|
||||
ASSERT_EQ(p.abs(), "/foo");
|
||||
p.pop();
|
||||
ASSERT_EQ(p.abs(), "/");
|
||||
}
|
||||
|
||||
TEST(CanonPath, removePrefix) {
|
||||
CanonPath p1("foo/bar");
|
||||
CanonPath p2("foo/bar/a/b/c");
|
||||
ASSERT_EQ(p2.removePrefix(p1).abs(), "/a/b/c");
|
||||
ASSERT_EQ(p1.removePrefix(p1).abs(), "/");
|
||||
ASSERT_EQ(p1.removePrefix(CanonPath("/")).abs(), "/foo/bar");
|
||||
}
|
||||
|
||||
TEST(CanonPath, iter) {
|
||||
{
|
||||
CanonPath p("a//foo/bar//");
|
||||
std::vector<std::string_view> ss;
|
||||
for (auto & c : p) ss.push_back(c);
|
||||
ASSERT_EQ(ss, std::vector<std::string_view>({"a", "foo", "bar"}));
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p("/");
|
||||
std::vector<std::string_view> ss;
|
||||
for (auto & c : p) ss.push_back(c);
|
||||
ASSERT_EQ(ss, std::vector<std::string_view>());
|
||||
}
|
||||
}
|
||||
|
||||
TEST(CanonPath, concat) {
|
||||
{
|
||||
CanonPath p1("a//foo/bar//");
|
||||
CanonPath p2("xyzzy/bla");
|
||||
ASSERT_EQ((p1 + p2).abs(), "/a/foo/bar/xyzzy/bla");
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p1("/");
|
||||
CanonPath p2("/a/b");
|
||||
ASSERT_EQ((p1 + p2).abs(), "/a/b");
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p1("/a/b");
|
||||
CanonPath p2("/");
|
||||
ASSERT_EQ((p1 + p2).abs(), "/a/b");
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p("/foo/bar");
|
||||
ASSERT_EQ((p + "x").abs(), "/foo/bar/x");
|
||||
}
|
||||
|
||||
{
|
||||
CanonPath p("/");
|
||||
ASSERT_EQ((p + "foo" + "bar").abs(), "/foo/bar");
|
||||
}
|
||||
}
|
||||
|
||||
TEST(CanonPath, within) {
|
||||
{
|
||||
ASSERT_TRUE(CanonPath("foo").isWithin(CanonPath("foo")));
|
||||
ASSERT_FALSE(CanonPath("foo").isWithin(CanonPath("bar")));
|
||||
ASSERT_FALSE(CanonPath("foo").isWithin(CanonPath("fo")));
|
||||
ASSERT_TRUE(CanonPath("foo/bar").isWithin(CanonPath("foo")));
|
||||
ASSERT_FALSE(CanonPath("foo").isWithin(CanonPath("foo/bar")));
|
||||
ASSERT_TRUE(CanonPath("/foo/bar/default.nix").isWithin(CanonPath("/")));
|
||||
ASSERT_TRUE(CanonPath("/").isWithin(CanonPath("/")));
|
||||
}
|
||||
}
|
||||
|
||||
TEST(CanonPath, sort) {
|
||||
ASSERT_FALSE(CanonPath("foo") < CanonPath("foo"));
|
||||
ASSERT_TRUE (CanonPath("foo") < CanonPath("foo/bar"));
|
||||
ASSERT_TRUE (CanonPath("foo/bar") < CanonPath("foo!"));
|
||||
ASSERT_FALSE(CanonPath("foo!") < CanonPath("foo"));
|
||||
ASSERT_TRUE (CanonPath("foo") < CanonPath("foo!"));
|
||||
}
|
||||
|
||||
TEST(CanonPath, allowed) {
|
||||
{
|
||||
std::set<CanonPath> allowed {
|
||||
CanonPath("foo/bar"),
|
||||
CanonPath("foo!"),
|
||||
CanonPath("xyzzy"),
|
||||
CanonPath("a/b/c"),
|
||||
};
|
||||
|
||||
ASSERT_TRUE (CanonPath("foo/bar").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("foo/bar/bla").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("foo").isAllowed(allowed));
|
||||
ASSERT_FALSE(CanonPath("bar").isAllowed(allowed));
|
||||
ASSERT_FALSE(CanonPath("bar/a").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("a").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("a/b").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("a/b/c").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("a/b/c/d").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("a/b/c/d/e").isAllowed(allowed));
|
||||
ASSERT_FALSE(CanonPath("a/b/a").isAllowed(allowed));
|
||||
ASSERT_FALSE(CanonPath("a/b/d").isAllowed(allowed));
|
||||
ASSERT_FALSE(CanonPath("aaa").isAllowed(allowed));
|
||||
ASSERT_FALSE(CanonPath("zzz").isAllowed(allowed));
|
||||
ASSERT_TRUE (CanonPath("/").isAllowed(allowed));
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in a new issue