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Task #2234

closed

Block abstraction: move constructor

Added by Alex Afanasyev over 9 years ago. Updated about 9 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Category:
Base
Target version:
Start date:
Due date:
% Done:

100%

Estimated time:
1.00 h

Description

Implement move constructors for Block and Buffer types.

Static assertions should be declared (in implementation .cpp, on supported platforms) to guarantee those types are move constructible.

Actions #1

Updated by Junxiao Shi over 9 years ago

  • Subject changed from Implement move constructor for Block abstraction to Block abstraction: move constructor
  • Description updated (diff)
  • Status changed from New to In Progress
  • Assignee set to Junxiao Shi
  • Estimated time set to 1.00 h

I'll code this as a learning experience, so time estimation might be higher than it's supposed to be.

Actions #2

Updated by Davide Pesavento over 9 years ago

You should also implement a move assignment operator then...

Actions #3

Updated by Junxiao Shi over 9 years ago

  • % Done changed from 0 to 40

Buffer http://gerrit.named-data.net/1478

Buffer is already move constructible. A static_assert is added.

I'll add move constructor to Block in the next commit.

Actions #4

Updated by Junxiao Shi over 9 years ago

You should also implement a move assignment operator then...

I agree.

Is there a type property from <type_traits> that I can use to guarantee a type has move assignment operator?

From MoveAssignable reference:

The type does not have to implement move assignment operator in order to satisfy this type requirement: a copy assignment operator that takes its parameter by value or as a const Type&, will bind to rvalue argument.

Actions #5

Updated by Davide Pesavento over 9 years ago

Junxiao Shi wrote:

Is there a type property from <type_traits> that I can use to guarantee a type has move assignment operator?

Use std::is_move_assignable. Of course that doesn't guarantee that your type implements move semantics, that's a different thing and it only depends on how you implement the body of the move constructor and the move assignment operator.

From MoveAssignable reference:

The type does not have to implement move assignment operator in order to satisfy this type requirement: a copy assignment operator that takes its parameter by value or as a const Type&, will bind to rvalue argument.

Obviously... the same is true for MoveConstructible and a copy constructor (which takes a const reference).

Actions #6

Updated by Junxiao Shi over 9 years ago

From http://en.cppreference.com/w/cpp/language/move_constructor:

For non-union class types (class and struct), the move constructor performs full member-wise move of the object's bases and non-static members, in their initialization order, using direct initialization with an xvalue argument.

Therefore, Block type already has a move constructor and a move assignment operator that can satisfy the needs.

I'll just add static assertions.

Actions #7

Updated by Junxiao Shi over 9 years ago

  • Status changed from In Progress to Code review
  • % Done changed from 40 to 100

http://gerrit.named-data.net/1489

It seems that implicitly-defined move constructor is generated, as seen in the symbol table:

shijunxiao@vm104:~/ndn-cxx$ nm --demangle=auto build/libndn-cxx.a | grep Block::Block | sort -u
0000000000000000 n ndn::Block::Block(ndn::Block&&)
0000000000000000 n ndn::Block::Block(ndn::Block const&)
0000000000000000 W ndn::Block::Block(ndn::Block&&)
0000000000000000 W ndn::Block::Block(ndn::Block const&)
0000000000000198 T ndn::Block::Block()
00000000000001e8 T ndn::Block::Block(std::shared_ptr<ndn::Buffer const> const&, unsigned int, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&)
0000000000000258 T ndn::Block::Block(unsigned int)
00000000000002a4 T ndn::Block::Block(unsigned int, std::shared_ptr<ndn::Buffer const> const&)
00000000000022da T ndn::Block::Block(ndn::EncodingImpl<true> const&)
00000000000028a6 T ndn::Block::Block(std::shared_ptr<ndn::Buffer const> const&)
0000000000002e74 T ndn::Block::Block(std::shared_ptr<ndn::Buffer const> const&, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&, bool)
000000000000344a T ndn::Block::Block(unsigned int, ndn::Block const&)
00000000000047ba T ndn::Block::Block(unsigned char const*, unsigned long)
0000000000004f16 T ndn::Block::Block(void const*, unsigned long)
                 U ndn::Block::Block()
                 U ndn::Block::Block(std::shared_ptr<ndn::Buffer const> const&)
                 U ndn::Block::Block(std::shared_ptr<ndn::Buffer const> const&, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&, __gnu_cxx::__normal_iterator<unsigned char const*, std::vector<unsigned char, std::allocator<unsigned char> > > const&, bool)
                 U ndn::Block::Block(unsigned char const*, unsigned long)
                 U ndn::Block::Block(unsigned int)
                 U ndn::Block::Block(unsigned int, ndn::Block const&)
                 U ndn::Block::Block(unsigned int, std::shared_ptr<ndn::Buffer const> const&)
Actions #8

Updated by Junxiao Shi over 9 years ago

  • Blocked by Task #2263: code-style: Doxygen syntax added
Actions #9

Updated by Junxiao Shi over 9 years ago

  • Status changed from Code review to Resolved

This Task is blocked by #2263 because reviewer suggests in commit e71d53f7153caab9815c15ec203257353dd84a64 to follow a certain Doxygen code style which is not yet documented.

I'll wait for a guideline for Doxygen code style and then rework this Change.

Actions #10

Updated by Junxiao Shi about 9 years ago

  • Blocked by deleted (Task #2263: code-style: Doxygen syntax)
Actions #11

Updated by Junxiao Shi about 9 years ago

  • Status changed from Resolved to Closed
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