compilerplugins/clang/test/passstuffbyref.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #include <rtl/ustring.hxx>
  11 #include <o3tl/cow_wrapper.hxx>
  12 #include <vector>
  13
  14 #pragma clang diagnostic ignored "-Wunknown-warning-option" // for Clang < 13
  15 #pragma clang diagnostic ignored "-Wunused-but-set-variable"
  16
  17 struct S1 {
  18     OUString mv1;
  19     OUString const & get() const { return mv1; }
  20     OUString const & get2(bool) const { return mv1; }
  21 };
  22 struct S2 {
  23     OUString mv1;
  24     OUString mv2;
  25     OUString mv3[2];
  26     S1 child;
  27     static OUString gs1;
  28     o3tl::cow_wrapper<S1> mxCow;
  29
  30     // make sure we ignore cases where the passed in parameter is std::move'd
  31     S2(OUString v1, OUString v2)
  32       : mv1(std::move(v1)), mv2((std::move(v2))) {}
  33
  34     OUString get1() { return mv1; } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  35     OUString get2(bool b) { return b ? mv1 : mv2; } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  36     OUString get3() { return child.mv1; } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  37     OUString get4() { return mv3[0]; } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  38     OUString get5() { return gs1; } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  39     OUString const & get6() { return gs1; }
  40     OUString get7() { return get6(); } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  41     OUString & get8() { return gs1; }
  42     OUString get9() { return get8(); } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  43     // TODO
  44     OUString get10() { return OUString(*&get6()); } // todoexpected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  45     OUString get11() const { return mxCow->get(); } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  46     OUString get12() { return child.get2(false); } // expected-error {{rather return class rtl::OUString by const& than by value, to avoid unnecessary copying [loplugin:passstuffbyref]}}
  47
  48     // no warning expected
  49     OUString set1() { return OUString("xxx"); }
  50     OUString set2() { OUString v1("xxx"); return v1; }
  51     OUString set3() { S1 v1; return v1.get(); }
  52     OUString set4() { OUString v1[1]; return v1[0]; }
  53     OUString set5(OUString const & s) { return s; }
  54     OUString set6() { std::vector<OUString> v1(1); return v1[0]; }
  55     OUString set7(S1 const & s) { return s.get(); }
  56     OUString set8() { OUString * p = nullptr; return *p; }
  57 };
  58
  59
  60 // no warning expected
  61
  62 // Don't flag stuff where the local var is hidden behind a self-returning operation like -=:
  63 S2 &operator -= ( S2 &t1, const S2 &t2 );
  64 S2 operator-( const S2 &t1, const S2 &t2 )
  65 {
  66     S2 t0 = t1;
  67     return t0 -= t2;
  68 }
  69
  70 void f()
  71 {
  72     S2* s;
  73     OUString v1, v2;
  74     s = new S2(v1, v2);
  75 }
  76
  77 struct S3 { S3(int); };
  78
  79 S3 f2() {
  80     static int n;
  81     return n;
  82 }
  83
  84 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */