Fixes for use-static-qregular-expression

The check was warning on statements where the regex value is not known
e.g:

void fun(QString regex)
{
    str.contains(QRegularExpression(regex)); // Should not warn
}

3 files changed, 113 insertions, 26 deletions

diff --git a/src/checks/level0/use-static-qregularexpression.cpp b/src/checks/level0/use-static-qregularexpression.cpp
index ce078ef0..30a2ea85 100644
--- a/src/checks/level0/use-static-qregularexpression.cpp
+++ b/src/checks/level0/use-static-qregularexpression.cpp
@@ -39,24 +39,72 @@ UseStaticQRegularExpression::UseStaticQRegularExpression(const std::string &name
 {
 }
 
-static bool isArgNonStaticLocalVar(Expr *arg0)
+static MaterializeTemporaryExpr* isArgTemporaryObj(Expr *arg0)
 {
-    auto declRefExpr = dyn_cast_or_null<DeclRefExpr>(clazy::getFirstChild(arg0));
+    return dyn_cast_or_null<MaterializeTemporaryExpr>(arg0);
+}
+
+static VarDecl* getVarDecl(Expr *arg)
+{
+    auto declRefExpr = dyn_cast_or_null<DeclRefExpr>(clazy::getFirstChild(arg));
     if (!declRefExpr) {
+        return nullptr;
+    }
+    return dyn_cast_or_null<VarDecl>(declRefExpr->getDecl());
+}
+
+static Expr* getVarInitExpr(VarDecl *VDef)
+{
+    return VDef->getDefinition() ? VDef->getDefinition()->getInit() : nullptr;
+}
+
+static bool isQStringFromStringLiteral(Expr *qstring)
+{
+    if (isArgTemporaryObj(qstring)) {
+        return true;
+    }
+
+    if (auto *VD = getVarDecl(qstring)) {
+        auto *stringLit = clazy::getFirstChildOfType<StringLiteral>(getVarInitExpr(VD));
+        if (stringLit) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool isQRegexpFromStringLiteral(VarDecl *qregexVarDecl)
+{
+    Expr *initExpr = getVarInitExpr(qregexVarDecl);
+    if (!initExpr) {
         return false;
     }
 
-    auto varDecl = dyn_cast_or_null<VarDecl>(declRefExpr->getDecl());
-    if (!varDecl) {
+    auto ctorCall = dyn_cast_or_null<CXXConstructExpr>(*initExpr->child_begin());
+    if (!ctorCall) {
         return false;
     }
 
-    return varDecl->isLocalVarDecl() && !varDecl->isStaticLocal();
+    auto qstringArg = ctorCall->getArg(0);
+    if (qstringArg && isQStringFromStringLiteral(qstringArg)) {
+        return true;
+    }
+
+    return false;
 }
 
-static bool isArgTemporaryObj(Expr *arg0)
+static bool isArgNonStaticLocalVar(Expr *qregexp)
 {
-    return dyn_cast_or_null<MaterializeTemporaryExpr>(arg0);
+    auto *varDecl = getVarDecl(qregexp);
+    if (!varDecl) {
+        return false;
+    }
+
+    if (!isQRegexpFromStringLiteral(varDecl)) {
+        return false;
+    }
+
+    return varDecl->isLocalVarDecl() && !varDecl->isStaticLocal();
 }
 
 static bool isQStringOrQStringListMethod(CXXMethodDecl *methodDecl)
@@ -92,18 +140,31 @@ void UseStaticQRegularExpression::VisitStmt(clang::Stmt *stmt)
         return;
     }
 
-    Expr* arg0 = method->getArg(0);
-    if (!arg0) {
+    Expr* qregexArg = method->getArg(0);
+    if (!qregexArg) {
         return;
     }
 
-    if (isArgTemporaryObj(arg0)) {
-        emitWarning(clazy::getLocStart(arg0), "Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead");
+    // Its a QRegularExpression(arg) ?
+    if (auto temp = isArgTemporaryObj(qregexArg)) {
+        // Get the QRegularExpression ctor
+        auto ctor = clazy::getFirstChildOfType<CXXConstructExpr>(temp);
+
+        // Check if its first arg is "QString" && a temporary OR non-static local
+        auto qstrArg = ctor->getArg(0);
+        if (!qstrArg || clazy::typeName(qstrArg->getType(), lo(), true) != "QString") {
+            return;
+        }
+
+        if (isQStringFromStringLiteral(qstrArg)) {
+            emitWarning(clazy::getLocStart(qregexArg), "Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead");
+        }
         return;
     }
 
-    if (isArgNonStaticLocalVar(arg0)) {
-        emitWarning(clazy::getLocStart(arg0), "Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead");
+    // Its a local QRegularExpression variable?
+    if (isArgNonStaticLocalVar(qregexArg)) {
+        emitWarning(clazy::getLocStart(qregexArg), "Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead");
         return;
     }
 }
diff --git a/tests/use-static-qregularexpression/main.cpp b/tests/use-static-qregularexpression/main.cpp
index 41e757d8..eaa63340 100644
--- a/tests/use-static-qregularexpression/main.cpp
+++ b/tests/use-static-qregularexpression/main.cpp
@@ -1,4 +1,3 @@
-#include <QtCore/QObject>
 #include <QtCore/QString>
 #include <QtCore/QRegularExpression>
 
@@ -53,4 +52,29 @@ void test()
 
     strList.lastIndexOf(e); // Warn
     strList.lastIndexOf(staticRegex); // Ok
+
+    QString regexStr = "[abc]";
+    h.contains(QRegularExpression(regexStr)); // Warn
+
+    {
+        QRegularExpression reg(regexStr);
+        h.contains(reg); // Warn
+    }
+    {
+        static const QRegularExpression reg(regexStr);
+        h.contains(reg); // Ok
+    }
+}
+
+void test1(const QString& regex, QString toCheck)
+{
+    QRegularExpression re(regex);
+    toCheck.contains(re); // Ok
+}
+
+void test2(const QStringList& regexes, QString toCheck)
+{
+    for (const auto& regix : regexes) {
+        toCheck.contains(QRegularExpression(regix)); // Ok, no warn
+    }
 }
diff --git a/tests/use-static-qregularexpression/main.cpp.expected b/tests/use-static-qregularexpression/main.cpp.expected
index a07a10e4..120a1557 100644
--- a/tests/use-static-qregularexpression/main.cpp.expected
+++ b/tests/use-static-qregularexpression/main.cpp.expected
@@ -1,19 +1,21 @@
-use-static-qregularexpression/main.cpp:7:33: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:11:24: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:14:24: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:6:33: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:10:24: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:13:24: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:20:19: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
 use-static-qregularexpression/main.cpp:21:19: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:22:19: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:24:13: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
 use-static-qregularexpression/main.cpp:25:13: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:26:13: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:28:15: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
 use-static-qregularexpression/main.cpp:29:15: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:30:15: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:32:14: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
 use-static-qregularexpression/main.cpp:33:14: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:34:14: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:36:15: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
 use-static-qregularexpression/main.cpp:37:15: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:38:15: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:40:13: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
 use-static-qregularexpression/main.cpp:41:13: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:42:13: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:44:16: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
 use-static-qregularexpression/main.cpp:45:16: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:46:16: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:51:21: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
-use-static-qregularexpression/main.cpp:54:25: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:50:21: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:53:25: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:57:16: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]
+use-static-qregularexpression/main.cpp:61:20: warning: Don't create temporary QRegularExpression objects. Use a static QRegularExpression object instead [-Wclazy-use-static-qregularexpression]