From 493961b6899e7f3471e7efa24ed251c7723adbcd Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 13 Jul 2020 18:22:56 +0200
Subject: [PATCH] Remove istringstream_nocopy

---
 src/libstore/derivations.cc           |  7 +-
 src/libstore/s3-binary-cache-store.cc |  5 +-
 src/libutil/hash.cc                   |  1 -
 src/libutil/istringstream_nocopy.hh   | 92 ---------------------------
 4 files changed, 5 insertions(+), 100 deletions(-)
 delete mode 100644 src/libutil/istringstream_nocopy.hh

diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index 42551ef6b..f325e511a 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -4,7 +4,6 @@
 #include "util.hh"
 #include "worker-protocol.hh"
 #include "fs-accessor.hh"
-#include "istringstream_nocopy.hh"
 
 namespace nix {
 
@@ -101,7 +100,7 @@ static StringSet parseStrings(std::istream & str, bool arePaths)
 }
 
 
-static DerivationOutput parseDerivationOutput(const Store & store, istringstream_nocopy & str)
+static DerivationOutput parseDerivationOutput(const Store & store, std::istringstream & str)
 {
     expect(str, ","); auto path = store.parseStorePath(parsePath(str));
     expect(str, ","); auto hashAlgo = parseString(str);
@@ -129,10 +128,10 @@ static DerivationOutput parseDerivationOutput(const Store & store, istringstream
 }
 
 
-static Derivation parseDerivation(const Store & store, const string & s)
+static Derivation parseDerivation(const Store & store, std::string && s)
 {
     Derivation drv;
-    istringstream_nocopy str(s);
+    std::istringstream str(std::move(s));
     expect(str, "Derive([");
 
     /* Parse the list of outputs. */
diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index 57f16101d..31ad4a3be 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -7,7 +7,6 @@
 #include "globals.hh"
 #include "compression.hh"
 #include "filetransfer.hh"
-#include "istringstream_nocopy.hh"
 
 #include <aws/core/Aws.h>
 #include <aws/core/VersionConfig.h>
@@ -266,7 +265,7 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
         const std::string & mimeType,
         const std::string & contentEncoding)
     {
-        auto stream = std::make_shared<istringstream_nocopy>(data);
+        auto stream = std::make_shared<std::stringstream>(data);
 
         auto maxThreads = std::thread::hardware_concurrency();
 
@@ -333,7 +332,7 @@ struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
             if (contentEncoding != "")
                 request.SetContentEncoding(contentEncoding);
 
-            auto stream = std::make_shared<istringstream_nocopy>(data);
+            auto stream = std::make_shared<std::stringstream>(data);
 
             request.SetBody(stream);
 
diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc
index 1a3e7c5d8..f0d7754d1 100644
--- a/src/libutil/hash.cc
+++ b/src/libutil/hash.cc
@@ -8,7 +8,6 @@
 #include "hash.hh"
 #include "archive.hh"
 #include "util.hh"
-#include "istringstream_nocopy.hh"
 
 #include <sys/types.h>
 #include <sys/stat.h>
diff --git a/src/libutil/istringstream_nocopy.hh b/src/libutil/istringstream_nocopy.hh
deleted file mode 100644
index f7beac578..000000000
--- a/src/libutil/istringstream_nocopy.hh
+++ /dev/null
@@ -1,92 +0,0 @@
-/* This file provides a variant of std::istringstream that doesn't
-   copy its string argument. This is useful for large strings. The
-   caller must ensure that the string object is not destroyed while
-   it's referenced by this object. */
-
-#pragma once
-
-#include <string>
-#include <iostream>
-
-template <class CharT, class Traits = std::char_traits<CharT>, class Allocator = std::allocator<CharT>>
-class basic_istringbuf_nocopy : public std::basic_streambuf<CharT, Traits>
-{
-public:
-    typedef std::basic_string<CharT, Traits, Allocator> string_type;
-
-    typedef typename std::basic_streambuf<CharT, Traits>::off_type off_type;
-
-    typedef typename std::basic_streambuf<CharT, Traits>::pos_type pos_type;
-
-    typedef typename std::basic_streambuf<CharT, Traits>::int_type int_type;
-
-    typedef typename std::basic_streambuf<CharT, Traits>::traits_type traits_type;
-
-private:
-    const string_type & s;
-
-    off_type off;
-
-public:
-    basic_istringbuf_nocopy(const string_type & s) : s{s}, off{0}
-    {
-    }
-
-private:
-    pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode which)
-    {
-        if (which & std::ios_base::in) {
-            this->off = dir == std::ios_base::beg
-                ? off
-                : (dir == std::ios_base::end
-                    ? s.size() + off
-                    : this->off + off);
-        }
-        return pos_type(this->off);
-    }
-
-    pos_type seekpos(pos_type pos, std::ios_base::openmode which)
-    {
-        return seekoff(pos, std::ios_base::beg, which);
-    }
-
-    std::streamsize showmanyc()
-    {
-        return s.size() - off;
-    }
-
-    int_type underflow()
-    {
-        if (typename string_type::size_type(off) == s.size())
-            return traits_type::eof();
-        return traits_type::to_int_type(s[off]);
-    }
-
-    int_type uflow()
-    {
-        if (typename string_type::size_type(off) == s.size())
-            return traits_type::eof();
-        return traits_type::to_int_type(s[off++]);
-    }
-
-    int_type pbackfail(int_type ch)
-    {
-        if (off == 0 || (ch != traits_type::eof() && ch != s[off - 1]))
-            return traits_type::eof();
-
-        return traits_type::to_int_type(s[--off]);
-    }
-
-};
-
-template <class CharT, class Traits = std::char_traits<CharT>, class Allocator = std::allocator<CharT>>
-class basic_istringstream_nocopy : public std::basic_iostream<CharT, Traits>
-{
-    typedef basic_istringbuf_nocopy<CharT, Traits, Allocator> buf_type;
-    buf_type buf;
-public:
-    basic_istringstream_nocopy(const typename buf_type::string_type & s) :
-        std::basic_iostream<CharT, Traits>(&buf), buf(s) {};
-};
-
-typedef basic_istringstream_nocopy<char> istringstream_nocopy;