Initial commit of Hyperscan

src/parser/check_refs.cpp

@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2015, Intel Corporation
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *  * Neither the name of Intel Corporation nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file
+ * \brief Component tree analysis that checks that references (such as
+ * back-refs, conditionals) have valid referents.
+ */
+#include "check_refs.h"
+#include "ComponentBackReference.h"
+#include "ComponentCondReference.h"
+#include "ConstComponentVisitor.h"
+#include "parse_error.h"
+#include "util/container.h"
+#include "util/ue2_containers.h"
+
+#include <sstream>
+
+using namespace std;
+
+namespace ue2 {
+
+/**
+ * \brief Visitor that checks the validity of references against a known list
+ * of indices and labels.
+ */
+class ReferenceVisitor: public DefaultConstComponentVisitor {
+private:
+    const size_t num_ids;
+    const flat_set<string> &names;
+
+public:
+    ReferenceVisitor(size_t num_groups, const flat_set<string> &targets)
+        : num_ids(num_groups), names(targets) {}
+
+    ~ReferenceVisitor();
+
+    void invalid_index(const char *component, unsigned id) {
+        assert(component);
+        ostringstream str;
+        str << "Invalid " << component << " to expression " << id << ".";
+        throw ParseError(str.str());
+    }
+
+    void invalid_label(const char *component, const std::string &label) {
+        assert(component);
+        ostringstream str;
+        str << "Invalid " << component << " to label '" << label << "'.";
+        throw ParseError(str.str());
+    }
+
+    void pre(const ComponentBackReference &c) override {
+        if (c.ref_id) {
+            if (c.ref_id >= num_ids) {
+                invalid_index("back reference", c.ref_id);
+            }
+        } else {
+            if (!contains(names, c.name)) {
+                invalid_label("back reference", c.name);
+            }
+        }
+    }
+
+    void pre(const ComponentCondReference &c) override {
+        switch (c.kind) {
+        case ComponentCondReference::CONDITION_NUMBER:
+            if (c.ref_id >= num_ids) {
+                invalid_index("conditional reference", c.ref_id);
+            }
+            break;
+        case ComponentCondReference::CONDITION_NAME:
+            if (c.ref_name == "DEFINE") {
+                // The string "DEFINE" is a special "always false" condition
+                // used to define subroutines.
+                break;
+            }
+            if (!contains(names, c.ref_name)) {
+                invalid_label("conditional reference", c.ref_name);
+            }
+            break;
+        case ComponentCondReference::CONDITION_ASSERTION:
+            break;
+        }
+    }
+};
+
+// Out-of-line destructor to silence weak vtable warnings.
+ReferenceVisitor::~ReferenceVisitor() {}
+
+void checkReferences(const Component &root, unsigned int groupIndices,
+                     const ue2::flat_set<std::string> &groupNames) {
+    ReferenceVisitor vis(groupIndices, groupNames);
+    root.accept(vis);
+}
+
+} // namespace ue2