forked from lix-project/lix
Restore `builtins.pathExists` behavior on broken symlinks
(cherry picked from commit d53c8901ef7f2033855dd99063522e3d56a19dab)
===
note that this variant differs markedly from the source commit because
we haven't endured quite as much lazy trees.
Change-Id: I0facf282f21fe0db4134be5c65a8368c1b3a06fc
157 lines
3.8 KiB
C++
157 lines
3.8 KiB
C++
#pragma once
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/**
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* @file
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*
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* @brief SourcePath
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*/
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#include "ref.hh"
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#include "canon-path.hh"
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#include "repair-flag.hh"
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#include "input-accessor.hh"
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namespace nix {
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/**
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* Note there is a decent chance this type soon goes away because the problem is solved another way.
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* See the discussion in https://github.com/NixOS/nix/pull/9985.
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*/
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enum class SymlinkResolution {
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/**
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* Resolve symlinks in the ancestors only.
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*
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* Only the last component of the result is possibly a symlink.
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*/
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Ancestors,
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/**
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* Resolve symlinks fully, realpath(3)-style.
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*
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* No component of the result will be a symlink.
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*/
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Full,
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};
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/**
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* An abstraction for accessing source files during
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* evaluation. Currently, it's just a wrapper around `CanonPath` that
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* accesses files in the regular filesystem, but in the future it will
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* support fetching files in other ways.
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*/
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struct SourcePath
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{
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CanonPath path;
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SourcePath(CanonPath path)
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: path(std::move(path))
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{ }
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std::string_view baseName() const;
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/**
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* Construct the parent of this `SourcePath`. Aborts if `this`
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* denotes the root.
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*/
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SourcePath parent() const;
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/**
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* If this `SourcePath` denotes a regular file (not a symlink),
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* return its contents; otherwise throw an error.
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*/
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std::string readFile() const
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{ return nix::readFile(path.abs()); }
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/**
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* Return whether this `SourcePath` denotes a file (of any type)
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* that exists
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*/
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bool pathExists() const
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{ return nix::pathExists(path.abs()); }
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/**
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* Return stats about this `SourcePath`, or throw an exception if
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* it doesn't exist.
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*/
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InputAccessor::Stat lstat() const;
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/**
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* Return stats about this `SourcePath`, or std::nullopt if it
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* doesn't exist.
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*/
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std::optional<InputAccessor::Stat> maybeLstat() const;
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/**
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* If this `SourcePath` denotes a directory (not a symlink),
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* return its directory entries; otherwise throw an error.
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*/
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InputAccessor::DirEntries readDirectory() const;
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/**
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* If this `SourcePath` denotes a symlink, return its target;
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* otherwise throw an error.
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*/
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std::string readLink() const
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{ return nix::readLink(path.abs()); }
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/**
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* Dump this `SourcePath` to `sink` as a NAR archive.
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*/
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void dumpPath(
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Sink & sink,
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PathFilter & filter = defaultPathFilter) const
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{ return nix::dumpPath(path.abs(), sink, filter); }
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/**
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* Return the location of this path in the "real" filesystem, if
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* it has a physical location.
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*/
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std::optional<CanonPath> getPhysicalPath() const
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{ return path; }
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std::string to_string() const
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{ return path.abs(); }
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/**
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* Append a `CanonPath` to this path.
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*/
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SourcePath operator + (const CanonPath & x) const
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{ return {path + x}; }
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/**
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* Append a single component `c` to this path. `c` must not
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* contain a slash. A slash is implicitly added between this path
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* and `c`.
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*/
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SourcePath operator + (std::string_view c) const
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{ return {path + c}; }
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bool operator == (const SourcePath & x) const
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{
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return path == x.path;
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}
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bool operator != (const SourcePath & x) const
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{
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return path != x.path;
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}
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bool operator < (const SourcePath & x) const
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{
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return path < x.path;
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}
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/**
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* Resolve any symlinks in this `SourcePath` according to the
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* given resolution mode.
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*
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* @param mode might only be a temporary solution for this.
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* See the discussion in https://github.com/NixOS/nix/pull/9985.
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*/
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SourcePath resolveSymlinks(
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SymlinkResolution mode = SymlinkResolution::Full) const;
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};
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std::ostream & operator << (std::ostream & str, const SourcePath & path);
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}
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