In O[U]StringBuffer, make string_view params replacements for OUString ones

...for LIBO_INTERNAL_ONLY, instead of having them as additional overloads.  That
way, loplugin:bufferadd and loplugin:stringviewparam found many further
opportunities for simplification (all addressed here).  Some notes:

* There is no longer an implicit conversion from O[U]String to O[U]StringBuffer
(as that goes via user-defined conversions through string_view now), which was
most noticeable in copy initializations like

  OStringBuffer buf = someStr;

that had to be changed to direct initialization,

  OStringBuffer buf(someStr);

But then again, it wasn't too many places that were affected and I think we can
live with that.

* I made the O[U]StringBuffer ctors taking string_view non-explicit, mainly to
get them in line with their counterparts taking O[U]String.

* I added an OUStringBuffer::lastIndexOf string_view overload that was missing
(relative to OUStringBuffer::indexOf).

* loplugin:stringconstant needed some addition to keep the
compilerplugins/clang/test/stringconstant.cxx checks related to
OStringBuffer::append and OStringBuffer::insert working.

* loplugin:stringviewparam no longer needs the special O[U]StringBuffer-related
code that had been introduced in 1250aecd71fabde4dba990bfceb61bbe8e06b8ea
"loplugin:stringviewparam extend to new.."

Change-Id: Ib1bb8c4632d99b744e742605a9fef6eae959fd72
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/122904
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

2 files changed, 7 insertions, 33 deletions

diff --git a/compilerplugins/clang/stringconstant.cxx b/compilerplugins/clang/stringconstant.cxx
index 9f51dad4f148..5c237afa1924 100644
--- a/compilerplugins/clang/stringconstant.cxx
+++ b/compilerplugins/clang/stringconstant.cxx
@@ -94,6 +94,12 @@ CXXConstructExpr const * lookForCXXConstructExpr(Expr const * expr) {
     if (auto e = dyn_cast<CXXBindTemporaryExpr>(expr)) {
         expr = e->getSubExpr();
     }
+    if (auto const e = dyn_cast<CXXMemberCallExpr>(expr)) {
+        // Look through OString::operator std::string_view:
+        if (auto const d = dyn_cast_or_null<CXXConversionDecl>(e->getCalleeDecl())) {
+            return lookForCXXConstructExpr(e->getImplicitObjectArgument()->IgnoreParenImpCasts());
+        }
+    }
     return dyn_cast<CXXConstructExpr>(expr);
 }
 
diff --git a/compilerplugins/clang/stringviewparam.cxx b/compilerplugins/clang/stringviewparam.cxx
index aa0899ca10a0..a500adf65d7c 100644
--- a/compilerplugins/clang/stringviewparam.cxx
+++ b/compilerplugins/clang/stringviewparam.cxx
@@ -65,23 +65,6 @@ StringType relevantStringType(QualType type)
     }
 }
 
-bool isRelevantStringBufferType(QualType type)
-{
-    loplugin::TypeCheck const c(type);
-    if (c.Class("OStringBuffer").Namespace("rtl"))
-    {
-        return true;
-    }
-    else if (c.Class("OUStringBuffer").Namespace("rtl"))
-    {
-        return true;
-    }
-    else
-    {
-        return false;
-    }
-}
-
 bool relevantParmVarDecl(ParmVarDecl const* decl)
 {
     auto const t1 = decl->getType();
@@ -139,28 +122,13 @@ DeclRefExpr const* relevantImplicitCastExpr(ImplicitCastExpr const* expr)
 
 DeclRefExpr const* relevantCXXMemberCallExpr(CXXMemberCallExpr const* expr)
 {
-    auto const d = expr->getMethodDecl();
-    if (isRelevantStringBufferType(compat::getObjectType(expr)))
-    {
-        if (auto const i = d->getIdentifier())
-        {
-            auto const n = i->getName();
-            if (n == "append" || n == "indexOf" || n == "lastIndexOf")
-            {
-                return relevantDeclRefExpr(expr->getArg(0));
-            }
-            else if (n == "insert")
-            {
-                return relevantDeclRefExpr(expr->getArg(1));
-            }
-        }
-    }
     StringType t = relevantStringType(compat::getObjectType(expr));
     if (t == StringType::None)
     {
         return nullptr;
     }
     bool good = false;
+    auto const d = expr->getMethodDecl();
     if (d->getOverloadedOperator() == OO_Subscript)
     {
         good = true;