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Give Json::Value move members and fix swap #339

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Give Json::Value move members and fix swap #339

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41f8f20
Give Json::Value move members
HowardHinnant Apr 18, 2014
1ef87f2
Fix Json::Value::swap
HowardHinnant Apr 30, 2014
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4 changes: 4 additions & 0 deletions src/ripple/json/api/json_value.h
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Original file line number Diff line number Diff line change
Expand Up @@ -215,6 +215,10 @@ class JSON_API Value
~Value ();

Value& operator= ( const Value& other );

Value ( Value&& other );
Value& operator= ( Value&& other );

/// Swap values.
/// \note Currently, comments are intentionally not swapped, for
/// both logic and efficiency.
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49 changes: 49 additions & 0 deletions src/ripple/json/impl/Tests.cpp
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Expand Up @@ -18,6 +18,7 @@
//==============================================================================

#include "../../../beast/beast/unit_test/suite.h"
#include "../../../beast/beast/utility/type_name.h"

namespace ripple {

Expand All @@ -37,9 +38,57 @@ class JsonCpp_test : public beast::unit_test::suite
pass ();
}

void
test_copy ()
{
Json::Value v1{2.5};
expect (v1.isDouble ());
expect (v1.asDouble () == 2.5);

Json::Value v2 = v1;
expect (v1.isDouble ());
expect (v1.asDouble () == 2.5);
expect (v2.isDouble ());
expect (v2.asDouble () == 2.5);
expect (v1 == v2);

v1 = v2;
expect (v1.isDouble ());
expect (v1.asDouble () == 2.5);
expect (v2.isDouble ());
expect (v2.asDouble () == 2.5);
expect (v1 == v2);

pass ();
}

void
test_move ()
{
Json::Value v1{2.5};
expect (v1.isDouble ());
expect (v1.asDouble () == 2.5);

Json::Value v2 = std::move(v1);
expect (v1.isNull ());
expect (v2.isDouble ());
expect (v2.asDouble () == 2.5);
expect (v1 != v2);

v1 = std::move(v2);
expect (v1.isDouble ());
expect (v1.asDouble () == 2.5);
expect (v2.isNull ());
expect (v1 != v2);

pass ();
}

void run ()
{
testBadJson ();
test_copy ();
test_move ();
}
};

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35 changes: 34 additions & 1 deletion src/ripple/json/impl/json_value.cpp
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Expand Up @@ -554,16 +554,49 @@ Value::operator= ( const Value& other )
return *this;
}

Value::Value ( Value&& other )
: value_ ( other.value_ )
, type_ ( other.type_ )
, allocated_ ( other.allocated_ )
# ifdef JSON_VALUE_USE_INTERNAL_MAP
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Now you have made this change, it seems clear to me that Value::swap isn't correct, because it doesn't swap the values of itemIsUsed_ and memberNameIsStatic_ in the case that JSON_VALUE_USE_INTERNAL_MAP is defined.

Is my reasoning correct? If so, could I convince you to make this change?

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On Apr 30, 2014, at 3:02 PM, Tom Swirly notifications@github.com wrote:

In src/ripple/json/impl/json_value.cpp:

@@ -554,6 +554,26 @@ Value::operator= ( const Value& other )
return *this;
}

+Value::Value ( Value&& other )

  • : value_ ( other.value_ )
  • , type_ ( other.type_ )
  • , allocated_ ( other.allocated_ )
    +# ifdef JSON_VALUE_USE_INTERNAL_MAP

Now you have made this change, it seems clear to me that Value::swap isn't correct, because it doesn't swap the values of itemIsUsed_ and memberNameIsStatic_ in the case that JSON_VALUE_USE_INTERNAL_MAP is defined.

Is my reasoning correct? If so, could I convince you to make this change?

Done (I think):

https://github.com/ripple/rippled/pull/339/commits

Howard

, itemIsUsed_ ( other.itemIsUsed_ )
, memberNameIsStatic_ ( other.memberNameIsStatic_ )
#endif // JSON_VALUE_USE_INTERNAL_MAP
, comments_ ( other.comments_ )
{
std::memset( &other, 0, sizeof(Value) );
}

Value&
Value::operator= ( Value&& other )
{
swap ( other );
return *this;
}

void
Value::swap ( Value& other )
{
std::swap ( value_, other.value_ );

ValueType temp = type_;
type_ = other.type_;
other.type_ = temp;
std::swap ( value_, other.value_ );

int temp2 = allocated_;
allocated_ = other.allocated_;
other.allocated_ = temp2;

# ifdef JSON_VALUE_USE_INTERNAL_MAP
unsigned temp3 = itemIsUsed_;
itemIsUsed_ = other.itemIsUsed_;
other.itemIsUsed_ = itemIsUsed_;

temp2 = memberNameIsStatic_;
memberNameIsStatic_ = other.memberNameIsStatic_;
other.memberNameIsStatic_ = temp2
# endif
std::swap(comments_, other.comments_);
}

ValueType
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