convert a for more utilities to string_view

src/libexpr/eval.hh

@@ -309,8 +309,8 @@ private:
     friend struct ExprAttrs;
     friend struct ExprLet;
 
-    Expr * parse(char * text, size_t length, FileOrigin origin, const Path & path,
-        const Path & basePath, StaticEnv & staticEnv);
+    Expr * parse(char * text, size_t length, FileOrigin origin, const PathView path,
+        const PathView basePath, StaticEnv & staticEnv);
 
 public:
 

src/libexpr/parser.y

@@ -598,7 +598,7 @@ namespace nix {
 
 
 Expr * EvalState::parse(char * text, size_t length, FileOrigin origin,
-    const Path & path, const Path & basePath, StaticEnv & staticEnv)
+    const PathView path, const PathView basePath, StaticEnv & staticEnv)
 {
     yyscan_t scanner;
     ParseData data(*this);

src/libstore/optimise-store.cc

@@ -26,7 +26,7 @@ static void makeWritable(const Path & path)
 struct MakeReadOnly
 {
     Path path;
-    MakeReadOnly(const Path & path) : path(path) { }
+    MakeReadOnly(const PathView path) : path(path) { }
     ~MakeReadOnly()
     {
         try {
@@ -205,12 +205,13 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
     /* Make the containing directory writable, but only if it's not
        the store itself (we don't want or need to mess with its
        permissions). */
-    bool mustToggle = dirOf(path) != realStoreDir.get();
-    if (mustToggle) makeWritable(dirOf(path));
+    const Path dirOfPath(dirOf(path));
+    bool mustToggle = dirOfPath != realStoreDir.get();
+    if (mustToggle) makeWritable(dirOfPath);
 
     /* When we're done, make the directory read-only again and reset
        its timestamp back to 0. */
-    MakeReadOnly makeReadOnly(mustToggle ? dirOf(path) : "");
+    MakeReadOnly makeReadOnly(mustToggle ? dirOfPath : "");
 
     Path tempLink = (format("%1%/.tmp-link-%2%-%3%")
         % realStoreDir % getpid() % random()).str();

src/libstore/parsed-derivations.cc

@@ -170,7 +170,7 @@ std::string writeStructuredAttrsShell(const nlohmann::json & json)
 
     auto handleSimpleType = [](const nlohmann::json & value) -> std::optional<std::string> {
         if (value.is_string())
-            return shellEscape(value);
+            return shellEscape(value.get<std::string_view>());
 
         if (value.is_number()) {
             auto f = value.get<float>();

src/libutil/util.cc

@@ -81,7 +81,7 @@ void replaceEnv(std::map<std::string, std::string> newEnv)
 }
 
 
-Path absPath(Path path, std::optional<Path> dir, bool resolveSymlinks)
+Path absPath(Path path, std::optional<PathView> dir, bool resolveSymlinks)
 {
     if (path[0] != '/') {
         if (!dir) {
@@ -95,12 +95,12 @@ Path absPath(Path path, std::optional<Path> dir, bool resolveSymlinks)
             if (!getcwd(buf, sizeof(buf)))
 #endif
                 throw SysError("cannot get cwd");
-            dir = buf;
+            path = concatStrings(buf, "/", path);
 #ifdef __GNU__
             free(buf);
 #endif
-        }
-        path = *dir + "/" + path;
+        } else
+            path = concatStrings(*dir, "/", path);
     }
     return canonPath(path, resolveSymlinks);
 }
@@ -172,7 +172,7 @@ Path canonPath(PathView path, bool resolveSymlinks)
 }
 
 
-Path dirOf(const Path & path)
+Path dirOf(const PathView path)
 {
     Path::size_type pos = path.rfind('/');
     if (pos == string::npos)
@@ -1344,9 +1344,11 @@ std::string toLower(const std::string & s)
 }
 
 
-std::string shellEscape(const std::string & s)
+std::string shellEscape(const std::string_view s)
 {
-    std::string r = "'";
+    std::string r;
+    r.reserve(s.size() + 2);
+    r += "'";
     for (auto & i : s)
         if (i == '\'') r += "'\\''"; else r += i;
     r += '\'';
@@ -1751,7 +1753,7 @@ void bind(int fd, const std::string & path)
 
     if (path.size() + 1 >= sizeof(addr.sun_path)) {
         Pid pid = startProcess([&]() {
-            auto dir = dirOf(path);
+            Path dir = dirOf(path);
             if (chdir(dir.c_str()) == -1)
                 throw SysError("chdir to '%s' failed", dir);
             std::string base(baseNameOf(path));
@@ -1780,7 +1782,7 @@ void connect(int fd, const std::string & path)
 
     if (path.size() + 1 >= sizeof(addr.sun_path)) {
         Pid pid = startProcess([&]() {
-            auto dir = dirOf(path);
+            Path dir = dirOf(path);
             if (chdir(dir.c_str()) == -1)
                 throw SysError("chdir to '%s' failed", dir);
             std::string base(baseNameOf(path));

src/libutil/util.hh

@@ -49,7 +49,7 @@ void clearEnv();
    specified directory, or the current directory otherwise.  The path
    is also canonicalised. */
 Path absPath(Path path,
-    std::optional<Path> dir = {},
+    std::optional<PathView> dir = {},
     bool resolveSymlinks = false);
 
 /* Canonicalise a path by removing all `.' or `..' components and
@@ -62,7 +62,7 @@ Path canonPath(PathView path, bool resolveSymlinks = false);
    everything before the final `/'.  If the path is the root or an
    immediate child thereof (e.g., `/foo'), this means `/'
    is returned.*/
-Path dirOf(const Path & path);
+Path dirOf(const PathView path);
 
 /* Return the base name of the given canonical path, i.e., everything
    following the final `/' (trailing slashes are removed). */
@@ -148,6 +148,9 @@ Path getDataDir();
 /* Create a directory and all its parents, if necessary.  Returns the
    list of created directories, in order of creation. */
 Paths createDirs(const Path & path);
+inline Paths createDirs(PathView path) {
+    return createDirs(Path(path));
+}
 
 /* Create a symlink. */
 void createSymlink(const Path & target, const Path & link,
@@ -187,6 +190,7 @@ public:
     void cancel();
     void reset(const Path & p, bool recursive = true);
     operator Path() const { return path; }
+    operator PathView() const { return path; }
 };
 
 
@@ -491,7 +495,7 @@ std::string toLower(const std::string & s);
 
 
 /* Escape a string as a shell word. */
-std::string shellEscape(const std::string & s);
+std::string shellEscape(const std::string_view s);
 
 
 /* Exception handling in destructors: print an error message, then

src/nix/develop.cc

@@ -472,9 +472,11 @@ struct CmdDevelop : Common, MixEnvironment
         else {
             script = "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc;\n" + script;
             if (developSettings.bashPrompt != "")
-                script += fmt("[ -n \"$PS1\" ] && PS1=%s;\n", shellEscape(developSettings.bashPrompt));
+                script += fmt("[ -n \"$PS1\" ] && PS1=%s;\n",
+                    shellEscape(developSettings.bashPrompt.get()));
             if (developSettings.bashPromptSuffix != "")
-                script += fmt("[ -n \"$PS1\" ] && PS1+=%s;\n", shellEscape(developSettings.bashPromptSuffix));
+                script += fmt("[ -n \"$PS1\" ] && PS1+=%s;\n",
+                    shellEscape(developSettings.bashPromptSuffix.get()));
         }
 
         writeFull(rcFileFd.get(), script);

src/resolve-system-dependencies/resolve-system-dependencies.cc

@@ -107,7 +107,7 @@ Path resolveSymlink(const Path & path)
     auto target = readLink(path);
     return hasPrefix(target, "/")
         ? target
-        : dirOf(path) + "/" + target;
+        : concatStrings(dirOf(path), "/", target);
 }
 
 std::set<string> resolveTree(const Path & path, PathSet & deps)