hscollider: tool for testing Hyperscan match behaviour against PCRE

tools/hscollider/DatabaseProxy.h

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+/*
+ * Copyright (c) 2015-2016, 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.
+ */
+
+#ifndef UE2COLLIDER_DATABASEPROXY_H
+#define UE2COLLIDER_DATABASEPROXY_H
+
+#include "UltimateTruth.h"
+
+#include <memory>
+#include <mutex>
+#include <set>
+#include <string>
+
+#include <boost/core/noncopyable.hpp>
+
+/**
+ * When a compile fails for the first time, we throw this exception so that a
+ * compilation error can be reported to the user. Subsequent failures will
+ * simply return nullptr rather than throwing this exception.
+ */
+struct CompileFailed {
+public:
+    explicit CompileFailed(const std::string &err) : error(err) {}
+    std::string error;
+};
+
+class DatabaseProxy : boost::noncopyable {
+public:
+    explicit DatabaseProxy(const std::set<unsigned> &expr_ids)
+        : ids(expr_ids) {}
+
+    explicit DatabaseProxy(std::shared_ptr<HyperscanDB> built_db)
+        : db(built_db) {}
+
+    std::shared_ptr<HyperscanDB> get(const UltimateTruth &ultimate) {
+        std::lock_guard<std::mutex> lock(mutex);
+        if (failed) {
+            // We have previously failed to compile this database.
+            return nullptr;
+        }
+        if (db) {
+            return db;
+        }
+
+        // Database hasn't been compiled yet.
+        std::string error;
+        db = ultimate.compile(ids, error);
+        if (!db) {
+            failed = true;
+            throw CompileFailed(error);
+        }
+
+        return db;
+    }
+
+private:
+    std::mutex mutex;
+    std::shared_ptr<HyperscanDB> db;
+    std::set<unsigned> ids;
+    bool failed = false; // Database failed compilation.
+};
+
+#endif // UE2COLLIDER_DATABASEPROXY_H