From a8eaaa0c3efac81262d956a71738c7ae30532671 Mon Sep 17 00:00:00 2001
From: Henning Baldersheim <balder@oath.com>
Date: Tue, 12 Jun 2018 12:30:36 +0200
Subject: If moving a non-owned buffer make sure to copy the buffer.

---
 .../src/tests/objects/nbostream/nbostream_test.cpp | 39 ++++++++++++++++++++++
 vespalib/src/vespa/vespalib/objects/nbostream.cpp  | 28 ++++++++++++++++
 vespalib/src/vespa/vespalib/objects/nbostream.h    |  6 ++--
 3 files changed, 70 insertions(+), 3 deletions(-)

(limited to 'vespalib')

diff --git a/vespalib/src/tests/objects/nbostream/nbostream_test.cpp b/vespalib/src/tests/objects/nbostream/nbostream_test.cpp
index 8b9ccb8a848..ab7265dfd69 100644
--- a/vespalib/src/tests/objects/nbostream/nbostream_test.cpp
+++ b/vespalib/src/tests/objects/nbostream/nbostream_test.cpp
@@ -7,6 +7,7 @@
 #include <ostream>
 
 using vespalib::nbostream;
+using vespalib::alloc::Alloc;
 using ExpBuffer = std::vector<uint8_t>;
 
 namespace std
@@ -60,6 +61,44 @@ struct Fixture
     }
 };
 
+TEST("test that move of owned buffer does not copy") {
+    Alloc buf = Alloc::allocHeap(1000);
+    const void * ptr = buf.get();
+    nbostream os(std::move(buf), 0);
+    os << static_cast<long>(0x567);
+    EXPECT_EQUAL(ptr, os.peek());
+    EXPECT_EQUAL(8ul, os.size());
+    nbostream moved(std::move(os));
+    EXPECT_TRUE(nullptr == os.peek());
+    EXPECT_EQUAL(0ul, os.size());
+    EXPECT_EQUAL(ptr, moved.peek());
+    EXPECT_EQUAL(8ul, moved.size());
+    long tmp(0);
+    moved >> tmp;
+    EXPECT_EQUAL(0x567l, tmp);
+}
+
+TEST("test that move of non-owned buffer does copy") {
+    Alloc buf = Alloc::allocHeap(1000);
+    const void * ptr = buf.get();
+    nbostream os(std::move(buf), 0);
+    os << static_cast<long>(0x567);
+    EXPECT_EQUAL(ptr, os.peek());
+    EXPECT_EQUAL(8ul, os.size());
+    nbostream refering(os.peek(), os.size());
+    EXPECT_EQUAL(ptr, os.peek());
+    EXPECT_EQUAL(8ul, os.size());
+    EXPECT_EQUAL(ptr, refering.peek());
+    EXPECT_EQUAL(8ul, refering.size());
+    nbostream moved(std::move(refering));
+    EXPECT_TRUE(nullptr == refering.peek());
+    EXPECT_EQUAL(0ul, refering.size());
+    EXPECT_TRUE(ptr != moved.peek());
+    EXPECT_EQUAL(8ul, moved.size());
+    long tmp(0);
+    moved >> tmp;
+    EXPECT_EQUAL(0x567l, tmp);
+}
 
 TEST_F("test serializing 64-bit signed integers", Fixture)
 {
diff --git a/vespalib/src/vespa/vespalib/objects/nbostream.cpp b/vespalib/src/vespa/vespalib/objects/nbostream.cpp
index ea9684efe01..871c88b5465 100644
--- a/vespalib/src/vespa/vespalib/objects/nbostream.cpp
+++ b/vespalib/src/vespa/vespalib/objects/nbostream.cpp
@@ -63,6 +63,33 @@ nbostream::nbostream(const nbostream & rhs) :
     memcpy(&_wbuf[0], &rhs._rbuf[rhs._rp], _wp);
 }
 
+nbostream::nbostream(nbostream && rhs) noexcept
+    : _wbuf(std::move(rhs._wbuf)),
+      _rbuf(rhs._rbuf),
+      _rp(rhs._rp),
+      _wp(rhs._wp),
+      _state(rhs._state),
+      _longLivedBuffer(rhs._longLivedBuffer)
+{
+    rhs._rp = 0;
+    rhs._wp = 0;
+    rhs._rbuf = ConstBufferRef();
+    if (!_longLivedBuffer && (_wbuf.capacity() == 0)) {
+        _wbuf.resize(roundUp2inN(_rbuf.size()));
+        memcpy(&_wbuf[0], &_rbuf[_rp], size());
+        _wp = size();
+        _rp = 0;
+        _rbuf = ConstBufferRef(&_wbuf[0], _wbuf.capacity());
+    }
+}
+
+nbostream &
+nbostream::operator = (nbostream && rhs) noexcept {
+    nbostream tmp(std::move(rhs));
+    swap(tmp);
+    return *this;
+}
+
 nbostream &
 nbostream::operator = (const nbostream & rhs) {
     if (this != &rhs) {
@@ -134,6 +161,7 @@ void nbostream::swap(nbostream & os)
     std::swap(_state, os._state);
     _wbuf.swap(os._wbuf);
     std::swap(_rbuf, os._rbuf);
+    std::swap(_longLivedBuffer, os._longLivedBuffer);
 }
 
 }
diff --git a/vespalib/src/vespa/vespalib/objects/nbostream.h b/vespalib/src/vespa/vespalib/objects/nbostream.h
index 70a590f79d1..b51fff1b7cc 100644
--- a/vespalib/src/vespa/vespalib/objects/nbostream.h
+++ b/vespalib/src/vespa/vespalib/objects/nbostream.h
@@ -28,11 +28,11 @@ public:
     nbostream(const void * buf, size_t sz);
     nbostream(Alloc && buf, size_t sz);
     nbostream(const nbostream & rhs);
-    nbostream(nbostream && rhs) noexcept = default;
+    nbostream(nbostream && rhs) noexcept;
 
     ~nbostream();
     nbostream & operator = (const nbostream & rhs);
-    nbostream & operator = (nbostream && rhs) noexcept = default;
+    nbostream & operator = (nbostream && rhs) noexcept;
 
     nbostream & operator << (double v)     { double n(nbo::n2h(v)); write8(&n); return *this; }
     nbostream & operator >> (double & v)   { double n; read8(&n); v = nbo::n2h(n); return *this; }
@@ -228,7 +228,7 @@ public:
     size_t         _rp;
     size_t         _wp;
     State          _state;
-    const bool     _longLivedBuffer;
+    bool           _longLivedBuffer;
 };
 
 class nbostream_longlivedbuf : public nbostream {
-- 
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