New loplugin:getstr

...to find matches of

  ... << s.getStr()

(for the rtl string classes) that can be written as just

  ... << s

Some notes:

* The OUStringToOString(..., RTL_TEXTENCODING_UTF8) is left explicit in
  desktop/source/app/crashreport.cxx (even though that would also be done
  internally by the "<< OUString" operator) to clarify that these values are
  written out as UTF-8 (and not as what that operator << happens to use, which
  just also happens to be UTF-8).

* OUSTRING_TO_CSTR (include/oox/helper/helper.hxx) is no longer used now.

* Just don't bother to use osl_getThreadTextEncoding() in the SAL_WARN in
  lingucomponent/source/hyphenator/hyphen/hyphenimp.cxx.

* The toUtf8() in the SAL_DEBUG in pyuno/source/module/pyuno_module.cxx can just
  go, too.

Change-Id: I4602f0379ef816bff310f1e51b57c56b7e3f0136
Reviewed-on: https://gerrit.libreoffice.org/80762
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

14 files changed, 264 insertions, 17 deletions

diff --git a/compilerplugins/clang/check.cxx b/compilerplugins/clang/check.cxx
index d53bfabbe9cf..be1b1f764eb1 100644
--- a/compilerplugins/clang/check.cxx
+++ b/compilerplugins/clang/check.cxx
@@ -10,6 +10,7 @@
 #include <cassert>
 
 #include <clang/AST/DeclCXX.h>
+#include <clang/AST/DeclTemplate.h>
 
 #include "check.hxx"
 
@@ -131,6 +132,21 @@ TypeCheck TypeCheck::Typedef() const {
     return TypeCheck();
 }
 
+DeclCheck TypeCheck::TemplateSpecializationClass() const {
+    if (!type_.isNull()) {
+        if (auto const t = type_->getAs<clang::TemplateSpecializationType>()) {
+            if (!t->isTypeAlias()) {
+                if (auto const d = llvm::dyn_cast_or_null<clang::ClassTemplateDecl>(
+                        t->getTemplateName().getAsTemplateDecl()))
+                {
+                    return DeclCheck(d->getTemplatedDecl());
+                }
+            }
+        }
+    }
+    return DeclCheck();
+}
+
 TypeCheck TypeCheck::NotSubstTemplateTypeParmType() const {
     return
         (!type_.isNull()
diff --git a/compilerplugins/clang/check.hxx b/compilerplugins/clang/check.hxx
index 7aa56cb8523d..8e835b8b6a96 100644
--- a/compilerplugins/clang/check.hxx
+++ b/compilerplugins/clang/check.hxx
@@ -29,6 +29,8 @@ inline ContextCheck checkRecordDecl(
 
 }
 
+class DeclCheck;
+
 class TypeCheck {
 public:
     explicit TypeCheck(clang::QualType type): type_(type) {}
@@ -71,6 +73,8 @@ public:
 
     inline ContextCheck Typedef(llvm::StringRef id) const;
 
+    DeclCheck TemplateSpecializationClass() const;
+
     TypeCheck NotSubstTemplateTypeParmType() const;
 
 private:
@@ -80,6 +84,8 @@ private:
 };
 
 class DeclCheck {
+    friend TypeCheck;
+
 public:
     explicit DeclCheck(clang::Decl const * decl): decl_(decl) {}
 
@@ -102,7 +108,9 @@ public:
     ContextCheck MemberFunction() const;
 
 private:
-    clang::Decl const * const decl_;
+    DeclCheck() = default;
+
+    clang::Decl const * const decl_ = nullptr;
 };
 
 class ContextCheck {
diff --git a/compilerplugins/clang/compat.hxx b/compilerplugins/clang/compat.hxx
index cb13f44cfa66..c091c51601f7 100644
--- a/compilerplugins/clang/compat.hxx
+++ b/compilerplugins/clang/compat.hxx
@@ -240,6 +240,19 @@ inline const clang::Expr *getSubExprAsWritten(const clang::CastExpr *This) {
   return getSubExprAsWritten(const_cast<clang::CastExpr *>(This));
 }
 
+inline clang::QualType getObjectType(clang::CXXMemberCallExpr const * expr) {
+#if CLANG_VERSION >= 100000
+    return expr->getObjectType();
+#else
+    // <https://github.com/llvm/llvm-project/commit/88559637641e993895337e1047a0bd787fecc647>
+    // "[OpenCL] Improve destructor support in C++ for OpenCL":
+    clang::QualType Ty = expr->getImplicitObjectArgument()->getType();
+    if (Ty->isPointerType())
+        Ty = Ty->getPointeeType();
+    return Ty;
+#endif
+}
+
 inline bool isExplicitSpecified(clang::CXXConstructorDecl const * decl) {
 #if CLANG_VERSION >= 90000
     return decl->getExplicitSpecifier().isExplicit();
diff --git a/compilerplugins/clang/getstr.cxx b/compilerplugins/clang/getstr.cxx
new file mode 100644
index 000000000000..15f340296bea
--- /dev/null
+++ b/compilerplugins/clang/getstr.cxx
@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include <cassert>
+#include <stack>
+
+#include "check.hxx"
+#include "compat.hxx"
+#include "plugin.hxx"
+
+// Find matches of
+//
+//   ... << s.getStr()
+//
+// (for the rtl string classes) that can be written as just
+//
+//   ... << s
+
+namespace
+{
+class GetStr final : public loplugin::FilteringPlugin<GetStr>
+{
+public:
+    explicit GetStr(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    bool PreTraverseFunctionDecl(FunctionDecl* decl)
+    {
+        functions_.push(decl);
+        return true;
+    }
+
+    bool PostTraverseFunctionDecl(FunctionDecl*, bool)
+    {
+        assert(!functions_.empty());
+        functions_.pop();
+        return true;
+    }
+
+    bool TraverseFunctionDecl(FunctionDecl* decl)
+    {
+        bool ret = true;
+        if (PreTraverseFunctionDecl(decl))
+        {
+            ret = FilteringPlugin::TraverseFunctionDecl(decl);
+            PostTraverseFunctionDecl(decl, ret);
+        }
+        return ret;
+    }
+
+    bool VisitCXXOperatorCallExpr(CXXOperatorCallExpr* expr)
+    {
+        if (ignoreLocation(expr))
+        {
+            return true;
+        }
+        if (expr->getOperator() != OO_LessLess)
+        {
+            return true;
+        }
+        assert(expr->getNumArgs() == 2);
+        if (!loplugin::TypeCheck(expr->getArg(0)->getType())
+                 .TemplateSpecializationClass()
+                 .ClassOrStruct("basic_ostream")
+                 .StdNamespace()) //TODO: check template args
+        {
+            return true;
+        }
+        auto const arg1 = expr->getArg(1);
+        auto const e = dyn_cast<CXXMemberCallExpr>(arg1->IgnoreParenImpCasts());
+        if (e == nullptr)
+        {
+            return true;
+        }
+        bool castToVoid = false;
+        if (auto const ic = dyn_cast<ImplicitCastExpr>(arg1))
+        {
+            if (loplugin::TypeCheck(arg1->getType()).Pointer().Void())
+            {
+                castToVoid = true;
+            }
+        }
+        auto const t = compat::getObjectType(e);
+        auto const tc = loplugin::TypeCheck(t);
+        if (!(tc.Class("OString").Namespace("rtl").GlobalNamespace()
+              || tc.Class("OUString").Namespace("rtl").GlobalNamespace()
+              || (castToVoid
+                  && (tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()
+                      || tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace()))))
+        {
+            return true;
+        }
+        if (!loplugin::DeclCheck(e->getMethodDecl()).Function("getStr"))
+        {
+            return true;
+        }
+        if (castToVoid)
+        {
+            report(DiagnosticsEngine::Warning,
+                   ("suspicious use of 'getStr' on an object of type %0; the result is implicitly"
+                    " cast to a void pointer in a call of 'operator <<'"),
+                   e->getExprLoc())
+                << t.getLocalUnqualifiedType() << expr->getSourceRange();
+            return true;
+        }
+        if (!functions_.empty())
+        {
+            // Filter out occurrences of `s << t.getStr()` in the implementation of
+            // `operator <<(std::basic_ostream<...> & s, T const & t)`:
+            auto const fd = functions_.top();
+            if (fd->getOverloadedOperator() == OO_LessLess)
+            {
+                assert(fd->getNumParams() == 2);
+                if (loplugin::TypeCheck(fd->getParamDecl(0)->getType())
+                        .LvalueReference()
+                        .NonConstVolatile()
+                        .TemplateSpecializationClass()
+                        .ClassOrStruct("basic_ostream")
+                        .StdNamespace()) //TODO: check template args
+                {
+                    if (auto const t2
+                        = fd->getParamDecl(1)->getType()->getAs<LValueReferenceType>())
+                    {
+                        auto const t3 = t2->getPointeeType();
+                        if (t3.isConstQualified() && !t3.isVolatileQualified()
+                            && (t3.getCanonicalType().getTypePtr()
+                                == t.getCanonicalType().getTypePtr()))
+                        {
+                            return true;
+                        }
+                    }
+                }
+            }
+        }
+        report(DiagnosticsEngine::Warning,
+               ("directly use object of type %0 in a call of 'operator <<', instead of calling"
+                " 'getStr' first"),
+               e->getExprLoc())
+            << t.getLocalUnqualifiedType() << expr->getSourceRange();
+        return true;
+    }
+
+    bool preRun() override { return compiler.getLangOpts().CPlusPlus; }
+
+private:
+    std::stack<FunctionDecl*> functions_;
+
+    void run() override
+    {
+        if (preRun())
+        {
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+        }
+    }
+};
+
+loplugin::Plugin::Registration<GetStr> getstr("getstr");
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/test/getstr.cxx b/compilerplugins/clang/test/getstr.cxx
new file mode 100644
index 000000000000..358f2e2b1e7d
--- /dev/null
+++ b/compilerplugins/clang/test/getstr.cxx
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <sal/config.h>
+
+#include <ostream>
+
+#include <rtl/strbuf.hxx>
+#include <rtl/string.hxx>
+#include <rtl/ustrbuf.hxx>
+#include <rtl/ustring.hxx>
+#include <sal/log.hxx>
+
+using S = OString;
+
+void f(std::ostream& st, OString const& s1, OStringBuffer const& s2, OUString const& s3,
+       OUStringBuffer const& s4, S const& s5, OString* p1, OStringBuffer* p2, OUString* p3,
+       OUStringBuffer* p4, S* p5, char const* (OString::*pf)() const)
+{
+    st << s1.getStr() // expected-error {{directly use object of type 'rtl::OString' in a call of 'operator <<', instead of calling 'getStr' first [loplugin:getstr]}}
+       << s2.getStr()
+       << s3.getStr() // expected-error {{suspicious use of 'getStr' on an object of type 'rtl::OUString'; the result is implicitly cast to a void pointer in a call of 'operator <<' [loplugin:getstr]}}
+       << s4.getStr() // expected-error {{suspicious use of 'getStr' on an object of type 'rtl::OUStringBuffer'; the result is implicitly cast to a void pointer in a call of 'operator <<' [loplugin:getstr]}}
+       << s5.getStr() // expected-error {{directly use object of type 'S' (aka 'rtl::OString') in a call of 'operator <<', instead of calling 'getStr' first [loplugin:getstr]}}
+       << p1->getStr() // expected-error {{directly use object of type 'rtl::OString' in a call of 'operator <<', instead of calling 'getStr' first [loplugin:getstr]}}
+       << p2->getStr()
+       << p3->getStr() // expected-error {{suspicious use of 'getStr' on an object of type 'rtl::OUString'; the result is implicitly cast to a void pointer in a call of 'operator <<' [loplugin:getstr]}}
+       << p4->getStr() // expected-error {{suspicious use of 'getStr' on an object of type 'rtl::OUStringBuffer'; the result is implicitly cast to a void pointer in a call of 'operator <<' [loplugin:getstr]}}
+       << p5->getStr() // expected-error {{directly use object of type 'rtl::OString' in a call of 'operator <<', instead of calling 'getStr' first [loplugin:getstr]}}
+       << (s1.*pf)();
+    SAL_INFO( // expected-error 1+ {{directly use object of type 'rtl::OString' in a call of 'operator <<', instead of calling 'getStr' first [loplugin:getstr]}}
+        "test", s1.getStr());
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/desktop/source/app/crashreport.cxx b/desktop/source/app/crashreport.cxx
index 794e4e6b6b63..3420f20c4496 100644
--- a/desktop/source/app/crashreport.cxx
+++ b/desktop/source/app/crashreport.cxx
@@ -50,8 +50,8 @@ void CrashReporter::writeToFile(std::ios_base::openmode Openmode)
 
     for (auto& keyValue : maKeyValues)
     {
-        ini_file << OUStringToOString(keyValue.first, RTL_TEXTENCODING_UTF8).getStr() << "=";
-        ini_file << OUStringToOString(keyValue.second, RTL_TEXTENCODING_UTF8).getStr() << "\n";
+        ini_file << OUStringToOString(keyValue.first, RTL_TEXTENCODING_UTF8) << "=";
+        ini_file << OUStringToOString(keyValue.second, RTL_TEXTENCODING_UTF8) << "\n";
     }
 
     maKeyValues.clear();
diff --git a/include/oox/helper/helper.hxx b/include/oox/helper/helper.hxx
index bc208af02662..d2077aaaa319 100644
--- a/include/oox/helper/helper.hxx
+++ b/include/oox/helper/helper.hxx
@@ -41,10 +41,6 @@ namespace oox {
 #define STATIC_ARRAY_SELECT( array, index, def ) \
     ((static_cast<size_t>(index) < SAL_N_ELEMENTS(array)) ? ((array)[static_cast<size_t>(index)]) : (def))
 
-/** Convert an OUString to an ASCII C string. Use for debug purposes only. */
-#define OUSTRING_TO_CSTR( str ) \
-    OUStringToOString( str, RTL_TEXTENCODING_ASCII_US ).getStr()
-
 // Common constants ===========================================================
 
 const sal_uInt8 WINDOWS_CHARSET_ANSI        = 0;
diff --git a/include/rtl/ustring.hxx b/include/rtl/ustring.hxx
index a7ede5f9a32a..a2bb6c09c086 100644
--- a/include/rtl/ustring.hxx
+++ b/include/rtl/ustring.hxx
@@ -3766,7 +3766,7 @@ inline std::basic_ostream<charT, traits> & operator <<(
     std::basic_ostream<charT, traits> & stream, OUString const & rString)
 {
     return stream <<
-        OUStringToOString(rString, RTL_TEXTENCODING_UTF8).getStr();
+        OUStringToOString(rString, RTL_TEXTENCODING_UTF8);
         // best effort; potentially loses data due to conversion failures
         // (stray surrogate halves) and embedded null characters
 }
diff --git a/lingucomponent/source/hyphenator/hyphen/hyphenimp.cxx b/lingucomponent/source/hyphenator/hyphen/hyphenimp.cxx
index 2008395319e0..3434482486ed 100644
--- a/lingucomponent/source/hyphenator/hyphen/hyphenimp.cxx
+++ b/lingucomponent/source/hyphenator/hyphen/hyphenimp.cxx
@@ -235,7 +235,7 @@ bool LoadDictionary(HDInfo& rDict)
     {
         SAL_WARN(
             "lingucomponent",
-            "Couldn't find file " << OU2ENC(dictpath, osl_getThreadTextEncoding()));
+            "Couldn't find file " << dictpath);
         return false;
     }
     rDict.aPtr = dict;
diff --git a/oox/source/ppt/commonbehaviorcontext.cxx b/oox/source/ppt/commonbehaviorcontext.cxx
index b94710777731..3112e084f8a6 100644
--- a/oox/source/ppt/commonbehaviorcontext.cxx
+++ b/oox/source/ppt/commonbehaviorcontext.cxx
@@ -91,7 +91,7 @@ namespace oox { namespace ppt {
                                                              RTL_TEXTENCODING_ASCII_US );
                         attr.type = attrConv->meAttribute;
                         maAttributes.push_back( attr );
-                        SAL_INFO("oox.ppt", "OOX: attrName is " << OUSTRING_TO_CSTR( msCurrentAttribute ) << " -> " << attrConv->mpAPIName );
+                        SAL_INFO("oox.ppt", "OOX: attrName is " << msCurrentAttribute << " -> " << attrConv->mpAPIName );
                         break;
                     }
                     attrConv++;
diff --git a/pyuno/source/module/pyuno_module.cxx b/pyuno/source/module/pyuno_module.cxx
index a6566182b546..715d5c6dbb27 100644
--- a/pyuno/source/module/pyuno_module.cxx
+++ b/pyuno/source/module/pyuno_module.cxx
@@ -863,7 +863,7 @@ static PyObject *sal_debug(
 
     OUString line = pyString2ustring( PyTuple_GetItem( args, 0 ) );
 
-    SAL_DEBUG(line.toUtf8().getStr());
+    SAL_DEBUG(line);
 
     return Py_None;
 }
diff --git a/sal/osl/unx/uunxapi.cxx b/sal/osl/unx/uunxapi.cxx
index 1005140a2c91..aecfab6d85a0 100644
--- a/sal/osl/unx/uunxapi.cxx
+++ b/sal/osl/unx/uunxapi.cxx
@@ -183,9 +183,9 @@ int osl::access(const OString& pstrPath, int mode)
     int result = ::access(fn.getStr(), mode);
     int saved_errno = errno;
     if (result == -1)
-        SAL_INFO("sal.file", "access(" << fn.getStr() << ",0" << std::oct << mode << std::dec << "): " << UnixErrnoString(saved_errno));
+        SAL_INFO("sal.file", "access(" << fn << ",0" << std::oct << mode << std::dec << "): " << UnixErrnoString(saved_errno));
     else
-        SAL_INFO("sal.file", "access(" << fn.getStr() << ",0" << std::oct << mode << std::dec << "): OK");
+        SAL_INFO("sal.file", "access(" << fn << ",0" << std::oct << mode << std::dec << "): OK");
 
     done_accessing_file_path(fn.getStr(), state);
 
@@ -232,9 +232,9 @@ template<typename T> bool realpath_(const T& pstrFileName, T& ppstrResolvedName)
     bool  bRet = realpath(fn.getStr(), rp);
     int   saved_errno = errno;
     if (!bRet)
-        SAL_INFO("sal.file", "realpath(" << fn.getStr() << "): " << UnixErrnoString(saved_errno));
+        SAL_INFO("sal.file", "realpath(" << fn << "): " << UnixErrnoString(saved_errno));
     else
-        SAL_INFO("sal.file", "realpath(" << fn.getStr() << "): OK");
+        SAL_INFO("sal.file", "realpath(" << fn << "): OK");
 
     done_accessing_file_path(fn.getStr(), state);
 
diff --git a/solenv/CompilerTest_compilerplugins_clang.mk b/solenv/CompilerTest_compilerplugins_clang.mk
index 644e8179180d..d83542bfbfc4 100644
--- a/solenv/CompilerTest_compilerplugins_clang.mk
+++ b/solenv/CompilerTest_compilerplugins_clang.mk
@@ -36,6 +36,7 @@ $(eval $(call gb_CompilerTest_add_exception_objects,compilerplugins_clang, \
     compilerplugins/clang/test/finalprotected \
     compilerplugins/clang/test/flatten \
     compilerplugins/clang/test/fragiledestructor \
+    compilerplugins/clang/test/getstr \
     compilerplugins/clang/test/indentation \
     compilerplugins/clang/test/logexceptionnicely \
     compilerplugins/clang/test/loopvartoosmall \
diff --git a/vcl/source/gdi/pdfwriter_impl.cxx b/vcl/source/gdi/pdfwriter_impl.cxx
index 49c2ca9050b8..0048cc548d54 100644
--- a/vcl/source/gdi/pdfwriter_impl.cxx
+++ b/vcl/source/gdi/pdfwriter_impl.cxx
@@ -10828,7 +10828,7 @@ bool PDFWriterImpl::setStructureAttribute( enum PDFWriter::StructAttribute eAttr
                  "rejecting setStructureAttribute( " << getAttributeTag( eAttr )
                  << ", " << getAttributeValueTag( eVal )
                  << " ) on " << getStructureTag( m_aStructure[ m_nCurrentStructElement ].m_eType )
-                 << " (" << m_aStructure[ m_nCurrentStructElement ].m_aAlias.getStr()
+                 << " (" << m_aStructure[ m_nCurrentStructElement ].m_aAlias
                  << ") element");
 
     return bInsert;
@@ -10960,7 +10960,7 @@ bool PDFWriterImpl::setStructureAttributeNumerical( enum PDFWriter::StructAttrib
                  "rejecting setStructureAttributeNumerical( " << getAttributeTag( eAttr )
                  << ", " << static_cast<int>(nValue)
                  << " ) on " << getStructureTag( m_aStructure[ m_nCurrentStructElement ].m_eType )
-                 << " (" << m_aStructure[ m_nCurrentStructElement ].m_aAlias.getStr()
+                 << " (" << m_aStructure[ m_nCurrentStructElement ].m_aAlias
                  << ") element");
 
     return bInsert;