loplugin:stringview

Add new methods "subView" to O(U)String to return substring views
of the underlying data.

Add a clang plugin to warn when replacing existing calls to copy()
would be better to use subView().

Change-Id: I03a5732431ce60808946f2ce2c923b22845689ca
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/105420
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 96 insertions, 0 deletions

diff --git a/compilerplugins/clang/test/stringview.cxx b/compilerplugins/clang/test/stringview.cxx
new file mode 100644
index 000000000000..96d4927e533a
--- /dev/null
+++ b/compilerplugins/clang/test/stringview.cxx
@@ -0,0 +1,96 @@
+/* -*- 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 <rtl/strbuf.hxx>
+#include <rtl/string.hxx>
+#include <rtl/ustrbuf.hxx>
+#include <rtl/ustring.hxx>
+
+void call_view(std::u16string_view) {}
+void call_view(std::string_view) {}
+struct ConstructWithView
+{
+    ConstructWithView(std::u16string_view) {}
+    ConstructWithView(std::string_view) {}
+};
+
+namespace test1
+{
+void f1(std::u16string_view s1)
+{
+    // no warning expected
+    call_view(s1);
+}
+void f1(std::string_view s1)
+{
+    // no warning expected
+    call_view(s1);
+}
+void f1(OUString s1)
+{
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    call_view(s1.copy(1, 2));
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    call_view(s1.copy(1));
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    ConstructWithView(s1.copy(1, 2));
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    ConstructWithView(s1.copy(1));
+}
+void f1(OString s1)
+{
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    call_view(s1.copy(1, 2));
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    call_view(s1.copy(1));
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    ConstructWithView(s1.copy(1, 2));
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    ConstructWithView(s1.copy(1));
+}
+}
+
+namespace test2
+{
+void f3(OUString s1)
+{
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    OUString s2 = s1.copy(1, 2) + "xxx";
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    s2 = s1.copy(1) + "xxx";
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    s2 = "xxx" + s1.copy(1);
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    s2 += s1.copy(1);
+}
+void f3(OString s1)
+{
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    OString s2 = s1.copy(1, 2) + "xxx";
+    (void)s2;
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    OString s3 = s1.copy(1) + "xxx";
+    (void)s3;
+}
+}
+
+namespace test3
+{
+void f4(OUString s1, OUString s2)
+{
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    sal_Unicode x = s2.copy(1, 2)[12];
+    (void)x;
+    // expected-error@+1 {{rather than copy, pass with a view using subView() [loplugin:stringview]}}
+    if (s2.copy(1, 2) < s1)
+        ;
+}
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */