Use static_cast instead of C-style casts for non-fundamental types #10498

pull practicalswift wants to merge 1 commits into bitcoin:master from practicalswift:static_cast changing 24 files +44 −44
  1. practicalswift commented at 12:35 PM on June 1, 2017: contributor

    A C-style cast is equivalent to try casting in the following order:

    1. const_cast(...)
    2. static_cast(...)
    3. const_cast(static_cast(...))
    4. reinterpret_cast(...)
    5. const_cast(reinterpret_cast(...))

    By using static_cast<T>(...) explicitly we avoid the possibility of an unintentional and dangerous reinterpret_cast. Furthermore static_cast<T>(...) allows for easier grepping of casts.

    For a more thorough discussion, see "ES.49: If you must use a cast, use a named cast" in the C++ Core Guidelines (Stroustrup & Sutter).

  2. fanquake added the label Refactoring on Jun 1, 2017
  3. in src/net_processing.cpp:2632 in 1a3c1e24cb outdated 
    2628 | @@ -2629,7 +2629,7 @@ static bool SendRejectsAndCheckIfBanned(CNode* pnode, CConnman& connman)
2629 |      CNodeState &state = *State(pnode->GetId());
2630 |  
2631 |      BOOST_FOREACH(const CBlockReject& reject, state.rejects) {
2632 | -        connman.PushMessage(pnode, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, (std::string)NetMsgType::BLOCK, reject.chRejectCode, reject.strRejectReason, reject.hashBlock));
2633 | +        connman.PushMessage(pnode, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, static_cast<std::string>(NetMsgType::BLOCK), reject.chRejectCode, reject.strRejectReason, reject.hashBlock));
    benma commented at 12:53 PM on June 1, 2017:

    maybe std::string(NetMsgType::BLOCK) is nicer here.

  4. in src/primitives/block.h:89 in 1a3c1e24cb outdated 
      85 | @@ -86,14 +86,14 @@ class CBlock : public CBlockHeader
  86 |      CBlock(const CBlockHeader &header)
  87 |      {
  88 |          SetNull();
  89 | -        *((CBlockHeader*)this) = header;
  90 | +        *(static_cast<CBlockHeader*>(this)) = header;
    benma commented at 12:58 PM on June 1, 2017:

    Why doesn't this need a cont_cast? this is const, isn't it?

    practicalswift commented at 9:12 PM on June 4, 2017:

    @benma this isn't const in the constructor:

    The type of this in a member function of class X is X* (pointer to X). If the member function is cv-qualified, the type of this is cv X* (pointer to identically cv-qualified X). Since constructors and destructors cannot be cv-qualified, the type of this in them is always X*, even when constructing or destroying a const object. (cppreference.com)

    benma commented at 9:20 PM on June 4, 2017:

    Of course, this is only const if the function is const. My bad.

  5. benma approved
  6. benma commented at 1:03 PM on June 1, 2017: none

    utACK 1a3c1e24cbce60910843f434dc6c489d03eaed1d

  7. practicalswift force-pushed on Jun 1, 2017
  8. practicalswift force-pushed on Jun 1, 2017
  9. benma commented at 9:28 PM on June 4, 2017: none

    utACK 6090e51b5d3f8024197a31e6a5a50b812ba10aca

  10. MarcoFalke commented at 4:02 PM on June 5, 2017: member

    utACK 6090e51b5d3f8024197a31e6a5a50b812ba10aca does not change the binariy on my platform

  11. practicalswift force-pushed on Jun 18, 2017
  12. practicalswift cross-referenced this on Jul 7, 2017 from issue Avoid dereference-of-casted-pointer by sipa
  13. practicalswift force-pushed on Jul 15, 2017
  14. practicalswift force-pushed on Jul 17, 2017
  15. practicalswift commented at 6:14 PM on July 17, 2017: contributor

    Rebased!

  16. practicalswift force-pushed on Aug 14, 2017
  17. practicalswift commented at 3:44 PM on August 14, 2017: contributor

    Rebased!

  18. practicalswift force-pushed on Sep 10, 2017
  19. practicalswift commented at 7:06 PM on September 10, 2017: contributor

    Rebased! :-)

  20. TheBlueMatt cross-referenced this on Sep 12, 2017 from issue Fix estimatesmartfee rounding display issue by TheBlueMatt
  21. practicalswift force-pushed on Sep 21, 2017
  22. practicalswift force-pushed on Sep 21, 2017
  23. Use static_cast instead of C-style casts for non-fundamental types
    A C-style cast is equivalent to try casting in the following order:

1. const_cast(...)
2. static_cast(...)
3. const_cast(static_cast(...))
4. reinterpret_cast(...)
5. const_cast(reinterpret_cast(...))

By using static_cast<T>(...) explicitly we avoid the possibility
of an unintentional and dangerous reinterpret_cast. Furthermore
static_cast<T>(...) allows for easier grepping of casts.
    9ad6746ccd
  24. practicalswift force-pushed on Sep 22, 2017
  25. practicalswift commented at 2:05 PM on September 22, 2017: contributor

    Rebased!

  26. practicalswift commented at 12:45 PM on January 31, 2018: contributor

    Anyone willing to review? ACK or NACK? :-)

  27. ghost commented at 5:34 PM on January 31, 2018: none

    Why not go the extra mile and also add -Wold-style-cast, otherwise you'll be back fixing it a week later.

  28. ryanofsky commented at 5:53 PM on January 31, 2018: contributor

    utACK 9ad6746ccd6dc31141fd0144686b641e31bf626b

  29. MarcoFalke commented at 6:07 PM on January 31, 2018: member

    re-reviewed

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  30. practicalswift commented at 8:33 AM on February 1, 2018: contributor

    @kekimusmaximus That would be nice but I think there might be some instances of C-style casts for non-fundamental types in our dependencies, no? :-)

  31. unknown cross-referenced this on Feb 1, 2018 from issue Use dynamic_cast for downcasting instead of static_cast. by ghost
  32. ryanofsky commented at 9:10 PM on February 7, 2018: contributor

    Seems like this could be merged: obvious change, has 3 acks.

  33. MarcoFalke merged this on Feb 7, 2018
  34. MarcoFalke closed this on Feb 7, 2018
  35. MarcoFalke referenced this in commit 0277173b1d on Feb 7, 2018
  36. ken2812221 cross-referenced this on Feb 9, 2018 from issue Windows Build Error by ken2812221
  37. in src/qt/bitcoin.cpp:712 in 9ad6746ccd 
     708 | @@ -709,7 +709,7 @@ int main(int argc, char *argv[])
 709 |          if (BitcoinCore::baseInitialize()) {
 710 |              app.requestInitialize();
 711 |  #if defined(Q_OS_WIN) && QT_VERSION >= 0x050000
 712 | -            WinShutdownMonitor::registerShutdownBlockReason(QObject::tr("%1 didn't yet exit safely...").arg(QObject::tr(PACKAGE_NAME)), (HWND)app.getMainWinId());
 713 | +            WinShutdownMonitor::registerShutdownBlockReason(QObject::tr("%1 didn't yet exit safely...").arg(QObject::tr(PACKAGE_NAME)), static_cast<HWND>(app.getMainWinId()));
    Sjors commented at 9:01 PM on February 10, 2018:

    ~Maybe unrelated, but~ I'm trying to make a Gitian Windows build for a branch based off of master and it throws:

    qt/bitcoin.cpp: In function ‘int main(int, char**)’:
qt/bitcoin.cpp:709:173: error: invalid static_cast from type ‘WId {aka unsigned int}’ to type ‘HWND’
             WinShutdownMonitor::registerShutdownBlockReason(QObject::tr("%1 didn't yet exit safely...").arg(QObject::tr(PACKAGE_NAME)), static_cast<HWND>(app.getMainWinId()));                                                                                                                                                                       ^
    Sjors commented at 9:09 PM on February 10, 2018:

    Just noticed #12386...

  38. practicalswift referenced this in commit f40df29d96 on Feb 12, 2018
  39. practicalswift cross-referenced this on Feb 12, 2018 from issue Fix Windows build errors introduced in #10498 by practicalswift
  40. ryanofsky cross-referenced this on Feb 12, 2018 from issue Add BitcoinApplication & RPCConsole tests by ryanofsky
  41. MarcoFalke referenced this in commit c997f88082 on Feb 12, 2018
  42. esotericnonsense referenced this in commit d4a24b5471 on Feb 19, 2018
  43. Willtech referenced this in commit a3fa7055aa on Feb 23, 2018
  44. HashUnlimited referenced this in commit d7183ebaf6 on Jul 31, 2018
  45. lionello referenced this in commit 8b245ac953 on Nov 7, 2018
  46. jasonbcox referenced this in commit 256ef1e899 on Apr 5, 2019
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  63. furszy cross-referenced this on Feb 4, 2021 from issue [Backport] Use static_cast instead of C-style casts for non-fundamental types by furszy
  64. random-zebra referenced this in commit 9232a36130 on Feb 13, 2021
  65. practicalswift deleted the branch on Apr 10, 2021
  66. PastaPastaPasta cross-referenced this on Dec 18, 2021 from issue docs: avoid C-style casts; use modern C++ casts by PastaPastaPasta
  67. gades referenced this in commit a0257555e7 on Feb 5, 2022
  68. bitcoin locked this on Aug 18, 2022
Contributors
practicalswiftbenmaMarcoFalkeghostryanofskySjors
Labels
Refactoring
Linked (view graph)
#10760 Avoid dereference-of-casted-pointer#11303 Fix estimatesmartfee rounding display issue#11625 Add BitcoinApplication & RPCConsole tests#12325 Use dynamic_cast for downcasting instead of static_cast.#12386 Windows Build Error#12416 Fix Windows build errors introduced in #10498#23810 docs: avoid C-style casts; use modern C++ casts
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