Merge pull request #11093 from NixOS/fix-concatStringsSep

Fix C++ `concatStringsSep`

src/build-remote/build-remote.cc

@@ -16,6 +16,7 @@
 #include "serialise.hh"
 #include "build-result.hh"
 #include "store-api.hh"
+#include "strings.hh"
 #include "derivations.hh"
 #include "local-store.hh"
 #include "legacy.hh"

src/libcmd/command.cc

@@ -1,3 +1,5 @@
+#include <nlohmann/json.hpp>
+
 #include "command.hh"
 #include "markdown.hh"
 #include "store-api.hh"
@@ -6,8 +8,7 @@
 #include "nixexpr.hh"
 #include "profiles.hh"
 #include "repl.hh"
-
-#include <nlohmann/json.hpp>
+#include "strings.hh"
 
 extern char * * environ __attribute__((weak));
 

src/libcmd/installables.cc

@@ -27,6 +27,8 @@
 
 #include <nlohmann/json.hpp>
 
+#include "strings-inline.hh"
+
 namespace nix {
 
 void completeFlakeInputPath(
@@ -374,6 +376,7 @@ void completeFlakeRefWithFragment(
                         auto attrPath2 = (*attr)->getAttrPath(attr2);
                         /* Strip the attrpath prefix. */
                         attrPath2.erase(attrPath2.begin(), attrPath2.begin() + attrPathPrefix.size());
+                        // FIXME: handle names with dots
                         completions.add(flakeRefS + "#" + prefixRoot + concatStringsSep(".", evalState->symbols.resolve(attrPath2)));
                     }
                 }

src/libcmd/repl.cc

@@ -33,6 +33,8 @@
 #include <gc/gc_cpp.h>
 #endif
 
+#include "strings.hh"
+
 namespace nix {
 
 /**

src/libexpr/eval-cache.cc

@@ -225,7 +225,7 @@ struct AttrDb
                 (key.first)
                 (symbols[key.second])
                 (AttrType::ListOfStrings)
-                (concatStringsSep("\t", l)).exec();
+                (dropEmptyInitThenConcatStringsSep("\t", l)).exec();
 
             return state->db.getLastInsertedRowId();
         });
@@ -435,12 +435,12 @@ std::vector<Symbol> AttrCursor::getAttrPath(Symbol name) const
 
 std::string AttrCursor::getAttrPathStr() const
 {
-    return concatStringsSep(".", root->state.symbols.resolve(getAttrPath()));
+    return dropEmptyInitThenConcatStringsSep(".", root->state.symbols.resolve(getAttrPath()));
 }
 
 std::string AttrCursor::getAttrPathStr(Symbol name) const
 {
-    return concatStringsSep(".", root->state.symbols.resolve(getAttrPath(name)));
+    return dropEmptyInitThenConcatStringsSep(".", root->state.symbols.resolve(getAttrPath(name)));
 }
 
 Value & AttrCursor::forceValue()

src/libexpr/eval.cc

@@ -49,6 +49,8 @@
 
 #endif
 
+#include "strings-inline.hh"
+
 using json = nlohmann::json;
 
 namespace nix {

src/libexpr/nixexpr.cc

@@ -7,6 +7,8 @@
 #include <cstdlib>
 #include <sstream>
 
+#include "strings-inline.hh"
+
 namespace nix {
 
 unsigned long Expr::nrExprs = 0;

src/libexpr/symbol-table.hh

@@ -41,6 +41,11 @@ public:
     }
 
     friend std::ostream & operator <<(std::ostream & os, const SymbolStr & symbol);
+
+    bool empty() const
+    {
+        return s->empty();
+    }
 };
 
 /**

src/libflake/flake/config.cc

@@ -47,7 +47,7 @@ void ConfigFile::apply(const Settings & flakeSettings)
         else if (auto* b = std::get_if<Explicit<bool>>(&value))
             valueS = b->t ? "true" : "false";
         else if (auto ss = std::get_if<std::vector<std::string>>(&value))
-            valueS = concatStringsSep(" ", *ss); // FIXME: evil
+            valueS = dropEmptyInitThenConcatStringsSep(" ", *ss); // FIXME: evil
         else
             assert(false);
 

src/libflake/flake/lockfile.cc

@@ -9,6 +9,8 @@
 #include <iterator>
 #include <nlohmann/json.hpp>
 
+#include "strings.hh"
+
 namespace nix::flake {
 
 static FlakeRef getFlakeRef(

src/libmain/shared.cc

@@ -23,6 +23,7 @@
 #include <openssl/crypto.h>
 
 #include "exit.hh"
+#include "strings.hh"
 
 namespace nix {
 

src/libstore/build/derivation-goal.cc

@@ -32,6 +32,8 @@
 
 #include <nlohmann/json.hpp>
 
+#include "strings.hh"
+
 namespace nix {
 
 DerivationGoal::DerivationGoal(const StorePath & drvPath,

src/libstore/build/entry-points.cc

@@ -4,6 +4,7 @@
 #  include "derivation-goal.hh"
 #endif
 #include "local-store.hh"
+#include "strings.hh"
 
 namespace nix {
 

src/libstore/derivations.cc

@@ -10,6 +10,8 @@
 #include <boost/container/small_vector.hpp>
 #include <nlohmann/json.hpp>
 
+#include "strings-inline.hh"
+
 namespace nix {
 
 std::optional<StorePath> DerivationOutput::path(const StoreDirConfig & store, std::string_view drvName, OutputNameView outputName) const

src/libstore/globals.cc

@@ -35,6 +35,8 @@
 #include <sys/sysctl.h>
 #endif
 
+#include "strings.hh"
+
 namespace nix {
 
 
@@ -82,7 +84,7 @@ Settings::Settings()
         Strings ss;
         for (auto & p : tokenizeString<Strings>(*s, ":"))
             ss.push_back("@" + p);
-        builders = concatStringsSep(" ", ss);
+        builders = concatStringsSep("\n", ss);
     }
 
 #if defined(__linux__) && defined(SANDBOX_SHELL)

src/libstore/local-store.cc

@@ -51,6 +51,8 @@
 
 #include <sqlite3.h>
 
+#include "strings.hh"
+
 
 namespace nix {
 

src/libstore/misc.cc

@@ -10,6 +10,7 @@
 #include "callback.hh"
 #include "closure.hh"
 #include "filetransfer.hh"
+#include "strings.hh"
 
 namespace nix {
 

src/libstore/nar-info-disk-cache.cc

@@ -7,6 +7,8 @@
 #include <sqlite3.h>
 #include <nlohmann/json.hpp>
 
+#include "strings.hh"
+
 namespace nix {
 
 static const char * schema = R"sql(

src/libstore/nar-info.cc

@@ -1,6 +1,7 @@
 #include "globals.hh"
 #include "nar-info.hh"
 #include "store-api.hh"
+#include "strings.hh"
 
 namespace nix {
 

src/libstore/outputs-spec.cc

@@ -5,6 +5,7 @@
 #include "regex-combinators.hh"
 #include "outputs-spec.hh"
 #include "path-regex.hh"
+#include "strings-inline.hh"
 
 namespace nix {
 

src/libstore/path-info.cc

@@ -4,6 +4,7 @@
 #include "store-api.hh"
 #include "json-utils.hh"
 #include "comparator.hh"
+#include "strings.hh"
 
 namespace nix {
 

src/libstore/path-info.hh

@@ -171,6 +171,9 @@ struct ValidPathInfo : UnkeyedValidPathInfo {
      */
     bool checkSignature(const Store & store, const PublicKeys & publicKeys, const std::string & sig) const;
 
+    /**
+     * References as store path basenames, including a self reference if it has one.
+     */
     Strings shortRefs() const;
 
     ValidPathInfo(const ValidPathInfo & other) = default;

src/libstore/path-with-outputs.cc

@@ -1,7 +1,9 @@
+#include <regex>
+
 #include "path-with-outputs.hh"
 #include "store-api.hh"
+#include "strings.hh"
 
-#include <regex>
 
 namespace nix {
 

src/libstore/store-api.cc

@@ -22,6 +22,8 @@
 #include <filesystem>
 #include <nlohmann/json.hpp>
 
+#include "strings.hh"
+
 using json = nlohmann::json;
 
 namespace nix {

src/libstore/unix/build/hook-instance.cc

@@ -3,6 +3,7 @@
 #include "hook-instance.hh"
 #include "file-system.hh"
 #include "child.hh"
+#include "strings.hh"
 
 namespace nix {
 

src/libstore/unix/build/local-derivation-goal.cc

@@ -64,6 +64,8 @@
 #include <grp.h>
 #include <iostream>
 
+#include "strings.hh"
+
 namespace nix {
 
 void handleDiffHook(

src/libutil/canon-path.cc

@@ -1,6 +1,7 @@
 #include "canon-path.hh"
 #include "util.hh"
 #include "file-path-impl.hh"
+#include "strings-inline.hh"
 
 namespace nix {
 

src/libutil/config.cc

@@ -9,6 +9,8 @@
 
 #include <nlohmann/json.hpp>
 
+#include "strings.hh"
+
 namespace nix {
 
 Config::Config(StringMap initials)
@@ -114,7 +116,7 @@ static void parseConfigFiles(const std::string & contents, const std::string & p
         if (tokens.empty()) continue;
 
         if (tokens.size() < 2)
-            throw UsageError("illegal configuration line '%1%' in '%2%'", line, path);
+            throw UsageError("syntax error in configuration line '%1%' in '%2%'", line, path);
 
         auto include = false;
         auto ignoreMissing = false;
@@ -127,7 +129,7 @@ static void parseConfigFiles(const std::string & contents, const std::string & p
 
         if (include) {
             if (tokens.size() != 2)
-                throw UsageError("illegal configuration line '%1%' in '%2%'", line, path);
+                throw UsageError("syntax error in configuration line '%1%' in '%2%'", line, path);
             auto p = absPath(tokens[1], dirOf(path));
             if (pathExists(p)) {
                 try {
@@ -143,7 +145,7 @@ static void parseConfigFiles(const std::string & contents, const std::string & p
         }
 
         if (tokens[1] != "=")
-            throw UsageError("illegal configuration line '%1%' in '%2%'", line, path);
+            throw UsageError("syntax error in configuration line '%1%' in '%2%'", line, path);
 
         std::string name = std::move(tokens[0]);
 

src/libutil/file-system.cc

@@ -23,6 +23,8 @@
 # include <io.h>
 #endif
 
+#include "strings-inline.hh"
+
 namespace fs = std::filesystem;
 
 namespace nix {

src/libutil/meson.build

@@ -148,6 +148,7 @@ sources = files(
   'signature/signer.cc',
   'source-accessor.cc',
   'source-path.cc',
+  'strings.cc',
   'suggestions.cc',
   'tarfile.cc',
   'terminal.cc',
@@ -215,6 +216,8 @@ headers = [config_h] + files(
   'source-accessor.hh',
   'source-path.hh',
   'split.hh',
+  'strings.hh',
+  'strings-inline.hh',
   'suggestions.hh',
   'sync.hh',
   'tarfile.hh',

src/libutil/strings-inline.hh

@@ -0,0 +1,31 @@
+#pragma once
+
+#include "strings.hh"
+
+namespace nix {
+
+template<class C>
+std::string concatStringsSep(const std::string_view sep, const C & ss)
+{
+    size_t size = 0;
+    bool tail = false;
+    // need a cast to string_view since this is also called with Symbols
+    for (const auto & s : ss) {
+        if (tail)
+            size += sep.size();
+        size += std::string_view(s).size();
+        tail = true;
+    }
+    std::string s;
+    s.reserve(size);
+    tail = false;
+    for (auto & i : ss) {
+        if (tail)
+            s += sep;
+        s += i;
+        tail = true;
+    }
+    return s;
+}
+
+} // namespace nix

src/libutil/strings.cc

@@ -0,0 +1,19 @@
+#include <string>
+
+#include "strings-inline.hh"
+#include "util.hh"
+
+namespace nix {
+
+template std::string concatStringsSep(std::string_view, const Strings &);
+template std::string concatStringsSep(std::string_view, const StringSet &);
+template std::string concatStringsSep(std::string_view, const std::vector<std::string> &);
+
+typedef std::string_view strings_2[2];
+template std::string concatStringsSep(std::string_view, const strings_2 &);
+typedef std::string_view strings_3[3];
+template std::string concatStringsSep(std::string_view, const strings_3 &);
+typedef std::string_view strings_4[4];
+template std::string concatStringsSep(std::string_view, const strings_4 &);
+
+} // namespace nix