Merge pull request #5932 from edolstra/remove-shared-strings

Remove shared strings

src/libutil/compression.cc

@@ -190,13 +190,13 @@ struct BrotliDecompressionSink : ChunkedCompressionSink
     }
 };
 
-ref<std::string> decompress(const std::string & method, const std::string & in)
+std::string decompress(const std::string & method, std::string_view in)
 {
     StringSink ssink;
     auto sink = makeDecompressionSink(method, ssink);
     (*sink)(in);
     sink->finish();
-    return ssink.s;
+    return std::move(ssink.s);
 }
 
 std::unique_ptr<FinishSink> makeDecompressionSink(const std::string & method, Sink & nextSink)
@@ -281,13 +281,13 @@ ref<CompressionSink> makeCompressionSink(const std::string & method, Sink & next
         throw UnknownCompressionMethod("unknown compression method '%s'", method);
 }
 
-ref<std::string> compress(const std::string & method, const std::string & in, const bool parallel, int level)
+std::string compress(const std::string & method, std::string_view in, const bool parallel, int level)
 {
     StringSink ssink;
     auto sink = makeCompressionSink(method, ssink, parallel, level);
     (*sink)(in);
     sink->finish();
-    return ssink.s;
+    return std::move(ssink.s);
 }
 
 }

src/libutil/compression.hh

@@ -15,11 +15,11 @@ struct CompressionSink : BufferedSink, FinishSink
     using FinishSink::finish;
 };
 
-ref<std::string> decompress(const std::string & method, const std::string & in);
+std::string decompress(const std::string & method, std::string_view in);
 
 std::unique_ptr<FinishSink> makeDecompressionSink(const std::string & method, Sink & nextSink);
 
-ref<std::string> compress(const std::string & method, const std::string & in, const bool parallel = false, int level = -1);
+std::string compress(const std::string & method, std::string_view in, const bool parallel = false, int level = -1);
 
 ref<CompressionSink> makeCompressionSink(const std::string & method, Sink & nextSink, const bool parallel = false, int level = -1);
 

src/libutil/error.hh

@@ -137,7 +137,7 @@ public:
     { }
 
     template<typename... Args>
-    BaseError(const std::string & fs, const Args & ... args)
+    explicit BaseError(const std::string & fs, const Args & ... args)
         : err { .level = lvlError, .msg = hintfmt(fs, args...) }
     { }
 

src/libutil/serialise.cc

@@ -110,7 +110,7 @@ std::string Source::drain()
 {
     StringSink s;
     drainInto(s);
-    return *s.s;
+    return std::move(s.s);
 }
 
 
@@ -325,7 +325,7 @@ void writeString(std::string_view data, Sink & sink)
 }
 
 
-Sink & operator << (Sink & sink, const string & s)
+Sink & operator << (Sink & sink, std::string_view s)
 {
     writeString(s, sink);
     return sink;
@@ -450,11 +450,11 @@ Error readError(Source & source)
 void StringSink::operator () (std::string_view data)
 {
     static bool warned = false;
-    if (!warned && s->size() > threshold) {
+    if (!warned && s.size() > threshold) {
         warnLargeDump();
         warned = true;
     }
-    s->append(data);
+    s.append(data);
 }
 
 size_t ChainSource::read(char * data, size_t len)

src/libutil/serialise.hh

@@ -154,12 +154,13 @@ private:
 /* A sink that writes data to a string. */
 struct StringSink : Sink
 {
-    ref<std::string> s;
-    StringSink() : s(make_ref<std::string>()) { };
-    explicit StringSink(const size_t reservedSize) : s(make_ref<std::string>()) {
-      s->reserve(reservedSize);
+    std::string s;
+    StringSink() { }
+    explicit StringSink(const size_t reservedSize)
+    {
+      s.reserve(reservedSize);
     };
-    StringSink(ref<std::string> s) : s(s) { };
+    StringSink(std::string && s) : s(std::move(s)) { };
     void operator () (std::string_view data) override;
 };
 
@@ -167,9 +168,9 @@ struct StringSink : Sink
 /* A source that reads data from a string. */
 struct StringSource : Source
 {
-    const string & s;
+    std::string_view s;
     size_t pos;
-    StringSource(const string & _s) : s(_s), pos(0) { }
+    StringSource(std::string_view s) : s(s), pos(0) { }
     size_t read(char * data, size_t len) override;
 };
 
@@ -317,10 +318,10 @@ inline Sink & operator << (Sink & sink, uint64_t n)
     return sink;
 }
 
-Sink & operator << (Sink & sink, const string & s);
+Sink & operator << (Sink & in, const Error & ex);
+Sink & operator << (Sink & sink, std::string_view s);
 Sink & operator << (Sink & sink, const Strings & s);
 Sink & operator << (Sink & sink, const StringSet & s);
-Sink & operator << (Sink & in, const Error & ex);
 
 
 MakeError(SerialisationError, Error);

src/libutil/tests/compression.cc

@@ -12,17 +12,17 @@ namespace nix {
     }
 
     TEST(compress, noneMethodDoesNothingToTheInput) {
-        ref<std::string> o = compress("none", "this-is-a-test");
+        auto o = compress("none", "this-is-a-test");
 
-        ASSERT_EQ(*o, "this-is-a-test");
+        ASSERT_EQ(o, "this-is-a-test");
     }
 
     TEST(decompress, decompressNoneCompressed) {
         auto method = "none";
         auto str = "slfja;sljfklsa;jfklsjfkl;sdjfkl;sadjfkl;sdjf;lsdfjsadlf";
-        ref<std::string> o = decompress(method, str);
+        auto o = decompress(method, str);
 
-        ASSERT_EQ(*o, str);
+        ASSERT_EQ(o, str);
     }
 
     TEST(decompress, decompressEmptyCompressed) {
@@ -30,33 +30,33 @@ namespace nix {
         // (Content-Encoding == "").
         auto method = "";
         auto str = "slfja;sljfklsa;jfklsjfkl;sdjfkl;sadjfkl;sdjf;lsdfjsadlf";
-        ref<std::string> o = decompress(method, str);
+        auto o = decompress(method, str);
 
-        ASSERT_EQ(*o, str);
+        ASSERT_EQ(o, str);
     }
 
     TEST(decompress, decompressXzCompressed) {
         auto method = "xz";
         auto str = "slfja;sljfklsa;jfklsjfkl;sdjfkl;sadjfkl;sdjf;lsdfjsadlf";
-        ref<std::string> o = decompress(method, *compress(method, str));
+        auto o = decompress(method, compress(method, str));
 
-        ASSERT_EQ(*o, str);
+        ASSERT_EQ(o, str);
     }
 
     TEST(decompress, decompressBzip2Compressed) {
         auto method = "bzip2";
         auto str = "slfja;sljfklsa;jfklsjfkl;sdjfkl;sadjfkl;sdjf;lsdfjsadlf";
-        ref<std::string> o = decompress(method, *compress(method, str));
+        auto o = decompress(method, compress(method, str));
 
-        ASSERT_EQ(*o, str);
+        ASSERT_EQ(o, str);
     }
 
     TEST(decompress, decompressBrCompressed) {
         auto method = "br";
         auto str = "slfja;sljfklsa;jfklsjfkl;sdjfkl;sadjfkl;sdjf;lsdfjsadlf";
-        ref<std::string> o = decompress(method, *compress(method, str));
+        auto o = decompress(method, compress(method, str));
 
-        ASSERT_EQ(*o, str);
+        ASSERT_EQ(o, str);
     }
 
     TEST(decompress, decompressInvalidInputThrowsCompressionError) {
@@ -77,7 +77,7 @@ namespace nix {
         (*sink)(inputString);
         sink->finish();
 
-        ASSERT_STREQ((*strSink.s).c_str(), inputString);
+        ASSERT_STREQ(strSink.s.c_str(), inputString);
     }
 
     TEST(makeCompressionSink, compressAndDecompress) {
@@ -90,7 +90,7 @@ namespace nix {
         sink->finish();
         decompressionSink->finish();
 
-        ASSERT_STREQ((*strSink.s).c_str(), inputString);
+        ASSERT_STREQ(strSink.s.c_str(), inputString);
     }
 
 }

src/libutil/util.cc

@@ -672,7 +672,7 @@ string drainFD(int fd, bool block, const size_t reserveSize)
     // not care very much about the extra memory.
     StringSink sink(reserveSize + 2);
     drainFD(fd, sink, block);
-    return std::move(*sink.s);
+    return std::move(sink.s);
 }
 
 
@@ -1057,7 +1057,7 @@ std::pair<int, std::string> runProgram(RunOptions && options)
         status = e.status;
     }
 
-    return {status, std::move(*sink.s)};
+    return {status, std::move(sink.s)};
 }
 
 void runProgram2(const RunOptions & options)