Adapt the remaining OUString functions to std string_view

...for LIBO_INTERNAL_ONLY.  These had been missed by
1b43cceaea2084a0489db68cd0113508f34b6643 "Make many OUString functions take
std::u16string_view parameters" because they did not match the multi-overload
pattern that was addressed there, but they nevertheless benefit from being
changed just as well (witness e.g. the various resulting changes from copy() to
subView()).

This showed a conversion from OStringChar to std::string_view to be missing
(while the corresponding conversion form OUStringChar to std::u16string_view was
already present).

The improvement to loplugin:stringadd became necessary to fix

> [CPT] compilerplugins/clang/test/stringadd.cxx
> error: 'error' diagnostics expected but not seen:
>   File ~/lo/core/compilerplugins/clang/test/stringadd.cxx Line 43 (directive at ~/lo/core/compilerplugins/clang/test/stringadd.cxx:42): simplify by merging with the preceding assignment [loplugin:stringadd]
>   File ~/lo/core/compilerplugins/clang/test/stringadd.cxx Line 61 (directive at ~/lo/core/compilerplugins/clang/test/stringadd.cxx:60): simplify by merging with the preceding assignment [loplugin:stringadd]
> 2 errors generated.

Change-Id: Ie40de0616a66e60e289c1af0ca60aed6f9ecc279
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107602
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 27 insertions, 9 deletions

diff --git a/compilerplugins/clang/stringadd.cxx b/compilerplugins/clang/stringadd.cxx
index 3410c2a6c436..b4994ab60ec6 100644
--- a/compilerplugins/clang/stringadd.cxx
+++ b/compilerplugins/clang/stringadd.cxx
@@ -291,18 +291,36 @@ bool StringAdd::isSideEffectFree(Expr const* expr)
     {
         // check for calls through OUString::number/OUString::unacquired
         if (auto calleeMethodDecl = dyn_cast_or_null<CXXMethodDecl>(callExpr->getCalleeDecl()))
-            if (calleeMethodDecl && calleeMethodDecl->getIdentifier())
+            if (calleeMethodDecl)
             {
-                auto name = calleeMethodDecl->getName();
-                if (callExpr->getNumArgs() > 0
-                    && (name == "number" || name == "unacquired" || name == "boolean"
-                        || name == "copy"))
+                if (calleeMethodDecl->getIdentifier())
                 {
-                    auto tc = loplugin::TypeCheck(calleeMethodDecl->getParent());
-                    if (tc.Class("OUString") || tc.Class("OString"))
+                    auto name = calleeMethodDecl->getName();
+                    if (callExpr->getNumArgs() > 0
+                        && (name == "number" || name == "unacquired" || name == "boolean"
+                            || name == "copy"))
                     {
-                        if (isSideEffectFree(callExpr->getArg(0)))
-                            return true;
+                        auto tc = loplugin::TypeCheck(calleeMethodDecl->getParent());
+                        if (tc.Class("OUString") || tc.Class("OString"))
+                        {
+                            if (isSideEffectFree(callExpr->getArg(0)))
+                                return true;
+                        }
+                    }
+                }
+                else if (auto const d = dyn_cast<CXXConversionDecl>(calleeMethodDecl))
+                {
+                    if (loplugin::TypeCheck(d->getConversionType())
+                            .ClassOrStruct("basic_string_view")
+                            .StdNamespace())
+                    {
+                        auto const tc = loplugin::TypeCheck(calleeMethodDecl->getParent());
+                        if (tc.Class("OUString").Namespace("rtl").GlobalNamespace()
+                            || tc.Class("OString").Namespace("rtl").GlobalNamespace())
+                        {
+                            if (isSideEffectFree(callExpr->getCallee()))
+                                return true;
+                        }
                     }
                 }
             }