1 files changed, 103 insertions, 0 deletions
diff --git a/SQLiteStudio3/coreSQLiteStudio/common/readwritelocker.cpp b/SQLiteStudio3/coreSQLiteStudio/common/readwritelocker.cpp
new file mode 100644
index 0000000..0eaca75
--- /dev/null
+++ b/SQLiteStudio3/coreSQLiteStudio/common/readwritelocker.cpp
@@ -0,0 +1,103 @@
+#include "readwritelocker.h"
+#include "parser/lexer.h"
+#include <QReadWriteLock>
+#include <QReadLocker>
+#include <QWriteLocker>
+
+ReadWriteLocker::ReadWriteLocker(QReadWriteLock* lock, Mode mode)
+{
+    init(lock, mode);
+}
+
+ReadWriteLocker::ReadWriteLocker(QReadWriteLock* lock, const QString& query, Dialect dialect, bool noLock)
+{
+    init(lock, getMode(query, dialect, noLock));
+}
+
+ReadWriteLocker::~ReadWriteLocker()
+{
+    if (readLocker)
+    {
+        delete readLocker;
+        readLocker = nullptr;
+    }
+
+    if (writeLocker)
+    {
+        delete writeLocker;
+        writeLocker = nullptr;
+    }
+}
+
+void ReadWriteLocker::init(QReadWriteLock* lock, ReadWriteLocker::Mode mode)
+{
+    switch (mode)
+    {
+        case ReadWriteLocker::READ:
+            readLocker = new QReadLocker(lock);
+            break;
+        case ReadWriteLocker::WRITE:
+            writeLocker = new QWriteLocker(lock);
+            break;
+        case ReadWriteLocker::NONE:
+            // Nothing to lock.
+            break;
+    }
+}
+
+ReadWriteLocker::Mode ReadWriteLocker::getMode(const QString &query, Dialect dialect, bool noLock)
+{
+    static QStringList readOnlyCommands = {"ANALYZE", "EXPLAIN", "PRAGMA"};
+
+    if (noLock)
+        return ReadWriteLocker::NONE;
+
+    TokenList tokens = Lexer::tokenize(query, dialect);
+    int keywordIdx = tokens.indexOf(Token::KEYWORD);
+
+    if (keywordIdx > -1 && readOnlyCommands.contains(tokens[keywordIdx]->value.toUpper()))
+        return ReadWriteLocker::READ;
+
+    if (keywordIdx > -1 && tokens[keywordIdx]->value.toUpper() == "WITH")
+    {
+        bool matched = false;
+        bool isSelect = false;
+        int depth = 0;
+        for (TokenPtr token : tokens)
+        {
+            switch (token->type)
+            {
+                case Token::PAR_LEFT:
+                    depth++;
+                    break;
+                case Token::PAR_RIGHT:
+                    depth--;
+                    break;
+                case Token::KEYWORD:
+                    if (depth == 0)
+                    {
+                        QString val = token->value.toUpper();
+                        if (val == "SELECT")
+                        {
+                            matched = true;
+                            isSelect = true;
+                        }
+                        else if (val == "DELETE" || val == "UPDATE" || val == "INSERT")
+                        {
+                            matched = true;
+                        }
+                    }
+                    break;
+                default:
+                    break;
+            }
+
+            if (matched)
+                break;
+        }
+        if (isSelect)
+            return ReadWriteLocker::READ;
+    }
+
+    return ReadWriteLocker::WRITE;
+}