Use std::filesystem::path in more places (#10657)

Progress on #9205

Co-Authored-By: John Ericson <John.Ericson@Obsidian.Systems>

* Get rid of `PathNG`, just use `std::filesystem::path`

src/libstore/ssh-store.cc

@@ -108,7 +108,7 @@ struct MountedSSHStoreConfig : virtual SSHStoreConfig, virtual LocalFSStoreConfi
     {
     }
 
-    const std::string name() override { return "Experimental SSH Store with filesytem mounted"; }
+    const std::string name() override { return "Experimental SSH Store with filesystem mounted"; }
 
     std::string doc() override
     {

src/libstore/ssh.cc

@@ -31,11 +31,11 @@ void SSHMaster::addCommonSSHOpts(Strings & args)
     if (!keyFile.empty())
         args.insert(args.end(), {"-i", keyFile});
     if (!sshPublicHostKey.empty()) {
-        Path fileName = (Path) *state->tmpDir + "/host-key";
+        std::filesystem::path fileName = state->tmpDir->path() / "host-key";
         auto p = host.rfind("@");
         std::string thost = p != std::string::npos ? std::string(host, p + 1) : host;
-        writeFile(fileName, thost + " " + base64Decode(sshPublicHostKey) + "\n");
-        args.insert(args.end(), {"-oUserKnownHostsFile=" + fileName});
+        writeFile(fileName.string(), thost + " " + base64Decode(sshPublicHostKey) + "\n");
+        args.insert(args.end(), {"-oUserKnownHostsFile=" + fileName.string()});
     }
     if (compress)
         args.push_back("-C");

src/libstore/unix/local-store.cc

@@ -1220,8 +1220,8 @@ StorePath LocalStore::addToStoreFromDump(
     }
 
     std::unique_ptr<AutoDelete> delTempDir;
-    Path tempPath;
-    Path tempDir;
+    std::filesystem::path tempPath;
+    std::filesystem::path tempDir;
     AutoCloseFD tempDirFd;
 
     bool methodsMatch = ContentAddressMethod(FileIngestionMethod(dumpMethod)) == hashMethod;
@@ -1237,9 +1237,9 @@ StorePath LocalStore::addToStoreFromDump(
 
         std::tie(tempDir, tempDirFd) = createTempDirInStore();
         delTempDir = std::make_unique<AutoDelete>(tempDir);
-        tempPath = tempDir + "/x";
+        tempPath = tempDir / "x";
 
-        restorePath(tempPath, bothSource, dumpMethod);
+        restorePath(tempPath.string(), bothSource, dumpMethod);
 
         dumpBuffer.reset();
         dump = {};
@@ -1252,7 +1252,7 @@ StorePath LocalStore::addToStoreFromDump(
         methodsMatch
             ? dumpHash
             : hashPath(
-                {getFSSourceAccessor(), CanonPath(tempPath)},
+                PosixSourceAccessor::createAtRoot(tempPath),
                 hashMethod.getFileIngestionMethod(), hashAlgo),
         {
             .others = references,
@@ -1295,7 +1295,7 @@ StorePath LocalStore::addToStoreFromDump(
                 }
             } else {
                 /* Move the temporary path we restored above. */
-                moveFile(tempPath, realPath);
+                moveFile(tempPath.string(), realPath);
             }
 
             /* For computing the nar hash. In recursive SHA-256 mode, this
@@ -1330,9 +1330,9 @@ StorePath LocalStore::addToStoreFromDump(
 
 /* Create a temporary directory in the store that won't be
    garbage-collected until the returned FD is closed. */
-std::pair<Path, AutoCloseFD> LocalStore::createTempDirInStore()
+std::pair<std::filesystem::path, AutoCloseFD> LocalStore::createTempDirInStore()
 {
-    Path tmpDirFn;
+    std::filesystem::path tmpDirFn;
     AutoCloseFD tmpDirFd;
     bool lockedByUs = false;
     do {
@@ -1345,7 +1345,7 @@ std::pair<Path, AutoCloseFD> LocalStore::createTempDirInStore()
             continue;
         }
         lockedByUs = lockFile(tmpDirFd.get(), ltWrite, true);
-    } while (!pathExists(tmpDirFn) || !lockedByUs);
+    } while (!pathExists(tmpDirFn.string()) || !lockedByUs);
     return {tmpDirFn, std::move(tmpDirFd)};
 }
 

src/libstore/unix/local-store.hh

@@ -377,7 +377,7 @@ private:
 
     void findRuntimeRoots(Roots & roots, bool censor);
 
-    std::pair<Path, AutoCloseFD> createTempDirInStore();
+    std::pair<std::filesystem::path, AutoCloseFD> createTempDirInStore();
 
     typedef std::unordered_set<ino_t> InodeHash;
 

src/libutil/experimental-features.cc

@@ -282,7 +282,7 @@ constexpr std::array<ExperimentalFeatureDetails, numXpFeatures> xpFeatureDetails
         .tag = Xp::MountedSSHStore,
         .name = "mounted-ssh-store",
         .description = R"(
-            Allow the use of the [`mounted SSH store`](@docroot@/command-ref/new-cli/nix3-help-stores.html#experimental-ssh-store-with-filesytem-mounted).
+            Allow the use of the [`mounted SSH store`](@docroot@/command-ref/new-cli/nix3-help-stores.html#experimental-ssh-store-with-filesystem-mounted).
         )",
         .trackingUrl = "https://github.com/NixOS/nix/milestone/43",
     },

src/libutil/file-path.hh

@@ -13,9 +13,8 @@ namespace nix {
  *
  * @todo drop `NG` suffix and replace the ones in `types.hh`.
  */
-typedef std::filesystem::path PathNG;
-typedef std::list<Path> PathsNG;
-typedef std::set<Path> PathSetNG;
+typedef std::list<std::filesystem::path> PathsNG;
+typedef std::set<std::filesystem::path> PathSetNG;
 
 /**
  * Stop gap until `std::filesystem::path_view` from P1030R6 exists in a
@@ -23,18 +22,18 @@ typedef std::set<Path> PathSetNG;
  *
  * @todo drop `NG` suffix and replace the one in `types.hh`.
  */
-struct PathViewNG : std::basic_string_view<PathNG::value_type>
+struct PathViewNG : std::basic_string_view<std::filesystem::path::value_type>
 {
-    using string_view = std::basic_string_view<PathNG::value_type>;
+    using string_view = std::basic_string_view<std::filesystem::path::value_type>;
 
     using string_view::string_view;
 
-    PathViewNG(const PathNG & path)
-        : std::basic_string_view<PathNG::value_type>(path.native())
+    PathViewNG(const std::filesystem::path & path)
+        : std::basic_string_view<std::filesystem::path::value_type>(path.native())
     { }
 
-    PathViewNG(const PathNG::string_type & path)
-        : std::basic_string_view<PathNG::value_type>(path)
+    PathViewNG(const std::filesystem::path::string_type & path)
+        : std::basic_string_view<std::filesystem::path::value_type>(path)
     { }
 
     const string_view & native() const { return *this; }
@@ -43,10 +42,19 @@ struct PathViewNG : std::basic_string_view<PathNG::value_type>
 
 std::string os_string_to_string(PathViewNG::string_view path);
 
-PathNG::string_type string_to_os_string(std::string_view s);
+std::filesystem::path::string_type string_to_os_string(std::string_view s);
 
-std::optional<PathNG> maybePathNG(PathView path);
+std::optional<std::filesystem::path> maybePath(PathView path);
 
-PathNG pathNG(PathView path);
+std::filesystem::path pathNG(PathView path);
+
+/**
+ * Create string literals with the native character width of paths
+ */
+#ifndef _WIN32
+# define PATHNG_LITERAL(s) s
+#else
+# define PATHNG_LITERAL(s) L ## s
+#endif
 
 }

src/libutil/file-system.cc

@@ -228,9 +228,9 @@ bool isLink(const Path & path)
 }
 
 
-std::vector<std::filesystem::directory_entry> readDirectory(const Path & path)
+std::vector<fs::directory_entry> readDirectory(const Path & path)
 {
-    std::vector<std::filesystem::directory_entry> entries;
+    std::vector<fs::directory_entry> entries;
     entries.reserve(64);
 
     for (auto & entry : fs::directory_iterator{path}) {
@@ -342,12 +342,12 @@ void syncParent(const Path & path)
 }
 
 
-static void _deletePath(Descriptor parentfd, const Path & path, uint64_t & bytesFreed)
+static void _deletePath(Descriptor parentfd, const fs::path & path, uint64_t & bytesFreed)
 {
 #ifndef _WIN32
     checkInterrupt();
 
-    std::string name(baseNameOf(path));
+    std::string name(baseNameOf(path.native()));
 
     struct stat st;
     if (fstatat(parentfd, name.c_str(), &st,
@@ -416,9 +416,9 @@ static void _deletePath(Descriptor parentfd, const Path & path, uint64_t & bytes
 #endif
 }
 
-static void _deletePath(const Path & path, uint64_t & bytesFreed)
+static void _deletePath(const fs::path & path, uint64_t & bytesFreed)
 {
-    Path dir = dirOf(path);
+    Path dir = dirOf(path.string());
     if (dir == "")
         dir = "/";
 
@@ -432,7 +432,7 @@ static void _deletePath(const Path & path, uint64_t & bytesFreed)
 }
 
 
-void deletePath(const Path & path)
+void deletePath(const fs::path & path)
 {
     uint64_t dummy;
     deletePath(path, dummy);
@@ -466,7 +466,7 @@ Paths createDirs(const Path & path)
 }
 
 
-void deletePath(const Path & path, uint64_t & bytesFreed)
+void deletePath(const fs::path & path, uint64_t & bytesFreed)
 {
     //Activity act(*logger, lvlDebug, "recursively deleting path '%1%'", path);
     bytesFreed = 0;
@@ -478,7 +478,7 @@ void deletePath(const Path & path, uint64_t & bytesFreed)
 
 AutoDelete::AutoDelete() : del{false} {}
 
-AutoDelete::AutoDelete(const std::string & p, bool recursive) : path(p)
+AutoDelete::AutoDelete(const fs::path & p, bool recursive) : _path(p)
 {
     del = true;
     this->recursive = recursive;
@@ -489,10 +489,9 @@ AutoDelete::~AutoDelete()
     try {
         if (del) {
             if (recursive)
-                deletePath(path);
+                deletePath(_path);
             else {
-                if (remove(path.c_str()) == -1)
-                    throw SysError("cannot unlink '%1%'", path);
+                fs::remove(_path);
             }
         }
     } catch (...) {
@@ -505,8 +504,8 @@ void AutoDelete::cancel()
     del = false;
 }
 
-void AutoDelete::reset(const Path & p, bool recursive) {
-    path = p;
+void AutoDelete::reset(const fs::path & p, bool recursive) {
+    _path = p;
     this->recursive = recursive;
     del = true;
 }

src/libutil/file-system.hh

@@ -9,6 +9,7 @@
 #include "error.hh"
 #include "logging.hh"
 #include "file-descriptor.hh"
+#include "file-path.hh"
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -149,9 +150,9 @@ void syncParent(const Path & path);
  * recursively. It's not an error if the path does not exist. The
  * second variant returns the number of bytes and blocks freed.
  */
-void deletePath(const Path & path);
+void deletePath(const std::filesystem::path & path);
 
-void deletePath(const Path & path, uint64_t & bytesFreed);
+void deletePath(const std::filesystem::path & path, uint64_t & bytesFreed);
 
 /**
  * Create a directory and all its parents, if necessary.  Returns the
@@ -197,17 +198,23 @@ void copyFile(const Path & oldPath, const Path & newPath, bool andDelete);
  */
 class AutoDelete
 {
-    Path path;
+    std::filesystem::path _path;
     bool del;
     bool recursive;
 public:
     AutoDelete();
-    AutoDelete(const Path & p, bool recursive = true);
+    AutoDelete(const std::filesystem::path & p, bool recursive = true);
     ~AutoDelete();
+
     void cancel();
-    void reset(const Path & p, bool recursive = true);
-    operator Path() const { return path; }
-    operator PathView() const { return path; }
+
+    void reset(const std::filesystem::path & p, bool recursive = true);
+
+    const std::filesystem::path & path() const { return _path; }
+    PathViewNG view() const { return _path; }
+
+    operator const std::filesystem::path & () const { return _path; }
+    operator PathViewNG () const { return _path; }
 };
 
 

src/libutil/unix/file-path.cc

@@ -13,17 +13,17 @@ std::string os_string_to_string(PathViewNG::string_view path)
     return std::string { path };
 }
 
-PathNG::string_type string_to_os_string(std::string_view s)
+std::filesystem::path::string_type string_to_os_string(std::string_view s)
 {
     return std::string { s };
 }
 
-std::optional<PathNG> maybePathNG(PathView path)
+std::optional<std::filesystem::path> maybePath(PathView path)
 {
     return { path };
 }
 
-PathNG pathNG(PathView path)
+std::filesystem::path pathNG(PathView path)
 {
     return path;
 }

src/libutil/windows/file-path.cc

@@ -12,35 +12,35 @@ namespace nix {
 std::string os_string_to_string(PathViewNG::string_view path)
 {
     std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
-    return converter.to_bytes(PathNG::string_type { path });
+    return converter.to_bytes(std::filesystem::path::string_type { path });
 }
 
-PathNG::string_type string_to_os_string(std::string_view s)
+std::filesystem::path::string_type string_to_os_string(std::string_view s)
 {
     std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
     return converter.from_bytes(std::string { s });
 }
 
-std::optional<PathNG> maybePathNG(PathView path)
+std::optional<std::filesystem::path> maybePath(PathView path)
 {
     if (path.length() >= 3 && (('A' <= path[0] && path[0] <= 'Z') || ('a' <= path[0] && path[0] <= 'z')) && path[1] == ':' && WindowsPathTrait<char>::isPathSep(path[2])) {
-        PathNG::string_type sw = string_to_os_string(
+        std::filesystem::path::string_type sw = string_to_os_string(
             std::string { "\\\\?\\" } + path);
         std::replace(sw.begin(), sw.end(), '/', '\\');
         return sw;
     }
     if (path.length() >= 7 && path[0] == '\\' && path[1] == '\\' && (path[2] == '.' || path[2] == '?') && path[3] == '\\' &&
                ('A' <= path[4] && path[4] <= 'Z') && path[5] == ':' && WindowsPathTrait<char>::isPathSep(path[6])) {
-        PathNG::string_type sw = string_to_os_string(path);
+        std::filesystem::path::string_type sw = string_to_os_string(path);
         std::replace(sw.begin(), sw.end(), '/', '\\');
         return sw;
     }
-    return std::optional<PathNG::string_type>();
+    return std::optional<std::filesystem::path::string_type>();
 }
 
-PathNG pathNG(PathView path)
+std::filesystem::path pathNG(PathView path)
 {
-    std::optional<PathNG::string_type> sw = maybePathNG(path);
+    std::optional<std::filesystem::path::string_type> sw = maybePath(path);
     if (!sw) {
         // FIXME why are we not using the regular error handling?
         std::cerr << "invalid path for WinAPI call ["<<path<<"]"<<std::endl;

src/nix-build/nix-build.cc

@@ -171,7 +171,7 @@ static void main_nix_build(int argc, char * * argv)
             ; // obsolete
 
         else if (*arg == "--no-out-link" || *arg == "--no-link")
-            outLink = (Path) tmpDir + "/result";
+            outLink = (tmpDir.path() / "result").string();
 
         else if (*arg == "--attr" || *arg == "-A")
             attrPaths.push_back(getArg(*arg, arg, end));
@@ -504,7 +504,7 @@ static void main_nix_build(int argc, char * * argv)
             if (passAsFile.count(var.first)) {
                 keepTmp = true;
                 auto fn = ".attr-" + std::to_string(fileNr++);
-                Path p = (Path) tmpDir + "/" + fn;
+                Path p = (tmpDir.path() / fn).string();
                 writeFile(p, var.second);
                 env[var.first + "Path"] = p;
             } else
@@ -536,10 +536,10 @@ static void main_nix_build(int argc, char * * argv)
                 auto json = structAttrs.value();
                 structuredAttrsRC = writeStructuredAttrsShell(json);
 
-                auto attrsJSON = (Path) tmpDir + "/.attrs.json";
+                auto attrsJSON = (tmpDir.path() / ".attrs.json").string();
                 writeFile(attrsJSON, json.dump());
 
-                auto attrsSH = (Path) tmpDir + "/.attrs.sh";
+                auto attrsSH = (tmpDir.path() / ".attrs.sh").string();
                 writeFile(attrsSH, structuredAttrsRC);
 
                 env["NIX_ATTRS_SH_FILE"] = attrsSH;
@@ -552,7 +552,7 @@ static void main_nix_build(int argc, char * * argv)
            convenience, source $stdenv/setup to setup additional
            environment variables and shell functions.  Also don't
            lose the current $PATH directories. */
-        auto rcfile = (Path) tmpDir + "/rc";
+        auto rcfile = (tmpDir.path() / "rc").string();
         std::string rc = fmt(
                 R"(_nix_shell_clean_tmpdir() { command rm -rf %1%; }; )"s +
                 (keepTmp ?
@@ -583,7 +583,7 @@ static void main_nix_build(int argc, char * * argv)
                 "unset TZ; %6%"
                 "shopt -s execfail;"
                 "%7%",
-                shellEscape(tmpDir),
+                shellEscape(tmpDir.path().string()),
                 (pure ? "" : "p=$PATH; "),
                 (pure ? "" : "PATH=$PATH:$p; unset p; "),
                 shellEscape(dirOf(*shell)),

src/nix/develop.cc

@@ -336,8 +336,8 @@ struct Common : InstallableCommand, MixProfile
     std::string makeRcScript(
         ref<Store> store,
         const BuildEnvironment & buildEnvironment,
-        const Path & tmpDir,
-        const Path & outputsDir = absPath(".") + "/outputs")
+        const std::filesystem::path & tmpDir,
+        const std::filesystem::path & outputsDir = std::filesystem::path { absPath(".") } / "outputs")
     {
         // A list of colon-separated environment variables that should be
         // prepended to, rather than overwritten, in order to keep the shell usable.
@@ -376,13 +376,19 @@ struct Common : InstallableCommand, MixProfile
         StringMap rewrites;
         if (buildEnvironment.providesStructuredAttrs()) {
             for (auto & [outputName, from] : BuildEnvironment::getAssociative(outputs->second)) {
-                rewrites.insert({from, outputsDir + "/" + outputName});
+                rewrites.insert({
+                    from,
+                    (outputsDir / outputName).string()
+                });
             }
         } else {
             for (auto & outputName : BuildEnvironment::getStrings(outputs->second)) {
                 auto from = buildEnvironment.vars.find(outputName);
                 assert(from != buildEnvironment.vars.end());
-                rewrites.insert({BuildEnvironment::getString(from->second), outputsDir + "/" + outputName});
+                rewrites.insert({
+                    BuildEnvironment::getString(from->second),
+                    (outputsDir / outputName).string(),
+                });
             }
         }
 
@@ -405,7 +411,7 @@ struct Common : InstallableCommand, MixProfile
 
         if (buildEnvironment.providesStructuredAttrs()) {
             fixupStructuredAttrs(
-                "sh",
+                PATHNG_LITERAL("sh"),
                 "NIX_ATTRS_SH_FILE",
                 buildEnvironment.getAttrsSH(),
                 rewrites,
@@ -413,7 +419,7 @@ struct Common : InstallableCommand, MixProfile
                 tmpDir
             );
             fixupStructuredAttrs(
-                "json",
+                PATHNG_LITERAL("json"),
                 "NIX_ATTRS_JSON_FILE",
                 buildEnvironment.getAttrsJSON(),
                 rewrites,
@@ -430,19 +436,21 @@ struct Common : InstallableCommand, MixProfile
      * that's accessible from the interactive shell session.
      */
     void fixupStructuredAttrs(
-        const std::string & ext,
+        PathViewNG::string_view ext,
         const std::string & envVar,
         const std::string & content,
         StringMap & rewrites,
         const BuildEnvironment & buildEnvironment,
-        const Path & tmpDir)
+        const std::filesystem::path & tmpDir)
     {
-        auto targetFilePath = tmpDir + "/.attrs." + ext;
-        writeFile(targetFilePath, content);
+        auto targetFilePath = tmpDir / PATHNG_LITERAL(".attrs.");
+        targetFilePath += ext;
+
+        writeFile(targetFilePath.string(), content);
 
         auto fileInBuilderEnv = buildEnvironment.vars.find(envVar);
         assert(fileInBuilderEnv != buildEnvironment.vars.end());
-        rewrites.insert({BuildEnvironment::getString(fileInBuilderEnv->second), targetFilePath});
+        rewrites.insert({BuildEnvironment::getString(fileInBuilderEnv->second), targetFilePath.string()});
     }
 
     Strings getDefaultFlakeAttrPaths() override
@@ -578,7 +586,7 @@ struct CmdDevelop : Common, MixEnvironment
 
         AutoDelete tmpDir(createTempDir("", "nix-develop"), true);
 
-        auto script = makeRcScript(store, buildEnvironment, (Path) tmpDir);
+        auto script = makeRcScript(store, buildEnvironment, tmpDir);
 
         if (verbosity >= lvlDebug)
             script += "set -x\n";

src/nix/prefetch.cc

@@ -87,7 +87,7 @@ std::tuple<StorePath, Hash> prefetchFile(
     if (!storePath) {
 
         AutoDelete tmpDir(createTempDir(), true);
-        Path tmpFile = (Path) tmpDir + "/tmp";
+        std::filesystem::path tmpFile = tmpDir.path() / "tmp";
 
         /* Download the file. */
         {
@@ -95,7 +95,7 @@ std::tuple<StorePath, Hash> prefetchFile(
             if (executable)
                 mode = 0700;
 
-            AutoCloseFD fd = toDescriptor(open(tmpFile.c_str(), O_WRONLY | O_CREAT | O_EXCL, mode));
+            AutoCloseFD fd = toDescriptor(open(tmpFile.string().c_str(), O_WRONLY | O_CREAT | O_EXCL, mode));
             if (!fd) throw SysError("creating temporary file '%s'", tmpFile);
 
             FdSink sink(fd.get());
@@ -109,15 +109,15 @@ std::tuple<StorePath, Hash> prefetchFile(
         if (unpack) {
             Activity act(*logger, lvlChatty, actUnknown,
                 fmt("unpacking '%s'", url));
-            Path unpacked = (Path) tmpDir + "/unpacked";
+            auto unpacked = (tmpDir.path() / "unpacked").string();
             createDirs(unpacked);
-            unpackTarfile(tmpFile, unpacked);
+            unpackTarfile(tmpFile.string(), unpacked);
 
             /* If the archive unpacks to a single file/directory, then use
                that as the top-level. */
             auto entries = readDirectory(unpacked);
             if (entries.size() == 1)
-                tmpFile = entries[0].path().string();
+                tmpFile = entries[0].path();
             else
                 tmpFile = unpacked;
         }