new loplugin:finalclasses

look for classes which are effectively final, but contain protected
members. These members can be made private.

Change-Id: If53d535b068b668d1aff548ebfd0fe6c51a48a0e

2 files changed, 190 insertions, 0 deletions

diff --git a/compilerplugins/clang/finalclasses.cxx b/compilerplugins/clang/finalclasses.cxx
new file mode 100644
index 000000000000..4b7a35804719
--- /dev/null
+++ b/compilerplugins/clang/finalclasses.cxx
@@ -0,0 +1,142 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * 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 <cassert>
+#include <set>
+#include <string>
+#include <iostream>
+#include "plugin.hxx"
+#include <fstream>
+
+/**
+Look for classes that are final i.e. nothing extends them, and have protected fields or members.
+
+These can be made private.
+
+The process goes something like this:
+  $ make check
+  $ make FORCE_COMPILE_ALL=1 COMPILER_PLUGIN_TOOL='FinalClasses' check
+  $ ./compilerplugins/clang/finalclasses.py
+
+*/
+
+namespace {
+
+// try to limit the voluminous output a little
+static std::set<std::string> inheritedFromSet;
+static std::map<std::string,std::string> definitionMap;  // className -> filename
+
+class FinalClasses:
+    public RecursiveASTVisitor<FinalClasses>, public loplugin::Plugin
+{
+public:
+    explicit FinalClasses(InstantiationData const & data): Plugin(data) {}
+
+    virtual void run() override
+    {
+        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+
+        // dump all our output in one write call - this is to try and limit IO "crosstalk" between multiple processes
+        // writing to the same logfile
+        std::string output;
+        for (const std::string & s : inheritedFromSet)
+            output += "inherited-from:\t" + s + "\n";
+        for (const std::pair<std::string,std::string> & s : definitionMap)
+            output += "definition:\t" + s.first + "\t" + s.second + "\n";
+        std::ofstream myfile;
+        myfile.open( SRCDIR "/loplugin.finalclasses.log", std::ios::app | std::ios::out);
+        myfile << output;
+        myfile.close();
+    }
+
+    bool shouldVisitTemplateInstantiations () const { return true; }
+
+    bool VisitCXXRecordDecl( const CXXRecordDecl* decl);
+};
+
+bool startsWith(const std::string& rStr, const char* pSubStr) {
+    return rStr.compare(0, strlen(pSubStr), pSubStr) == 0;
+}
+
+bool ignoreClass(StringRef s)
+{
+    // ignore stuff in the standard library, and UNO stuff we can't touch.
+    if (startsWith(s, "rtl::") || startsWith(s, "sal::") || startsWith(s, "com::sun::")
+        || startsWith(s, "std::") || startsWith(s, "boost::")
+        || s == "OString" || s == "OUString" || s == "bad_alloc")
+    {
+        return true;
+    }
+    return false;
+}
+
+bool FinalClasses::VisitCXXRecordDecl(const CXXRecordDecl* decl)
+{
+    if (ignoreLocation(decl))
+        return true;
+    decl = decl->getCanonicalDecl();
+    if (!decl->isThisDeclarationADefinition())
+        return true;
+
+    for (auto it = decl->bases_begin(); it != decl->bases_end(); ++it)
+    {
+        const CXXBaseSpecifier spec = *it;
+        // need to look through typedefs, hence the getUnqualifiedDesugaredType
+        QualType baseType = spec.getType().getDesugaredType(compiler.getASTContext());
+        std::string x;
+        // so that we get just the template name, excluding the template parameters
+        if (baseType->isRecordType())
+            x = baseType->getAsCXXRecordDecl()->getQualifiedNameAsString();
+        else if (auto templateType = baseType->getAs<TemplateSpecializationType>())
+            x = templateType->getTemplateName().getAsTemplateDecl()->getQualifiedNameAsString();
+        else
+            x = baseType.getAsString();
+        inheritedFromSet.insert( x );
+    }
+
+    bool bFoundProtected = false;
+    for (auto it = decl->method_begin(); it != decl->method_end(); ++it) {
+        auto i = *it;
+        // ignore methods that are overriding base-class methods, making them private
+        // isn't useful
+        if ( !i->hasAttr<OverrideAttr>() && i->getAccess() == AS_protected ) {
+            bFoundProtected = true;
+            break;
+        }
+    }
+    if (!bFoundProtected)
+    {
+        for (auto it = decl->field_begin(); it != decl->field_end(); ++it) {
+            auto i = *it;
+            if ( i->getAccess() == AS_protected ) {
+                bFoundProtected = true;
+                break;
+            }
+        }
+    }
+    if (!bFoundProtected)
+        return true;
+
+    std::string s = decl->getQualifiedNameAsString();
+    if (ignoreClass(s))
+        return true;
+
+    SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(decl->getLocStart());
+    std::string filename = compiler.getSourceManager().getFilename(spellingLocation);
+    auto sourceLocation = filename.substr(strlen(SRCDIR)) + ":"
+        + std::to_string(compiler.getSourceManager().getSpellingLineNumber(spellingLocation));
+    definitionMap.insert( std::pair<std::string,std::string>(s, sourceLocation) );
+    return true;
+}
+
+loplugin::Plugin::Registration< FinalClasses > X("finalclasses", false);
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/finalclasses.py b/compilerplugins/clang/finalclasses.py
new file mode 100755
index 000000000000..64d192905f7c
--- /dev/null
+++ b/compilerplugins/clang/finalclasses.py
@@ -0,0 +1,48 @@
+#!/usr/bin/python
+
+import re
+import sys
+
+definitionSet = set()
+inheritFromSet = set()
+definitionToFileDict = {}
+
+with open("loplugin.finalclasses.log") as txt:
+    for line in txt:
+        tokens = line.strip().split("\t")
+    
+        if len(tokens) == 1:
+            pass
+
+        elif tokens[0] == "definition:":
+            clazzName = tokens[1]
+            # the 1.. is so we skip the leading /
+            fileName  = tokens[2][1:]
+            definitionSet.add(clazzName)
+            definitionToFileDict[clazzName] = fileName
+            
+        elif tokens[0] == "inherited-from:":
+            parent = tokens[1]
+            if (parent.startswith("class ")):
+                parent = parent[6:]
+            elif (parent.startswith("struct ")):
+                parent = parent[7:]
+            inheritFromSet.add(parent);
+
+tmpset = set()
+for clazz in sorted(definitionSet - inheritFromSet):
+    tmpset.add((clazz, definitionToFileDict[clazz]))
+
+# sort the results using a "natural order" so sequences like [item1,item2,item10] sort nicely
+def natural_sort_key(s, _nsre=re.compile('([0-9]+)')):
+    return [int(text) if text.isdigit() else text.lower()
+            for text in re.split(_nsre, s)]
+def sort_set_by_natural_key(s):
+    return sorted(s, key=lambda v: natural_sort_key(v[1]))
+
+# print output, sorted by name and line number
+with open("compilerplugins/clang/finalclasses.results", "wt") as f:
+    for t in sort_set_by_natural_key(tmpset):
+        f.write(t[1] + "\n")
+        f.write("    " + t[0] + "\n")
+