Add InitFlow and move session states to context

r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/ConnectionContext.java

@@ -16,13 +16,16 @@
 
 package io.asyncer.r2dbc.mysql;
 
+import io.asyncer.r2dbc.mysql.cache.PrepareCache;
 import io.asyncer.r2dbc.mysql.codec.CodecContext;
 import io.asyncer.r2dbc.mysql.collation.CharCollation;
 import io.asyncer.r2dbc.mysql.constant.ServerStatuses;
 import io.asyncer.r2dbc.mysql.constant.ZeroDateOption;
+import io.r2dbc.spi.IsolationLevel;
 import org.jetbrains.annotations.Nullable;
 
 import java.nio.file.Path;
+import java.time.Duration;
 import java.time.ZoneId;
 
 import static io.asyncer.r2dbc.mysql.internal.util.AssertUtils.requireNonNull;
@@ -37,6 +40,10 @@ public final class ConnectionContext implements CodecContext {
 
     private static final ServerVersion NONE_VERSION = ServerVersion.create(0, 0, 0);
 
+    private static final ServerVersion MYSQL_5_7_4 = ServerVersion.create(5, 7, 4);
+
+    private static final ServerVersion MARIA_10_1_1 = ServerVersion.create(10, 1, 1, true);
+
     private final ZeroDateOption zeroDateOption;
 
     @Nullable
@@ -52,16 +59,47 @@ public final class ConnectionContext implements CodecContext {
 
     private Capability capability = Capability.DEFAULT;
 
+    private PrepareCache prepareCache;
+
     @Nullable
     private ZoneId timeZone;
 
+    private String product = "Unknown";
+
+    /**
+     * Current isolation level inferred by past statements.
+     * <p>
+     * Inference rules:
+     * <ol><li>In the beginning, it is also {@link #sessionIsolationLevel}.</li>
+     * <li>A transaction has began with a {@link IsolationLevel}, it will be changed to the value</li>
+     * <li>The transaction end (commit or rollback), it will recover to {@link #sessionIsolationLevel}.</li></ol>
+     */
+    private volatile IsolationLevel currentIsolationLevel;
+
+    /**
+     * Session isolation level.
+     *
+     * <ol><li>It is applied to all subsequent transactions performed within the current session.</li>
+     * <li>Calls {@link io.r2dbc.spi.Connection#setTransactionIsolationLevel}, it will change to the value.</li>
+     * <li>It can be changed within transactions, but does not affect the current ongoing transaction.</li></ol>
+     */
+    private volatile IsolationLevel sessionIsolationLevel;
+
     private boolean lockWaitTimeoutSupported = false;
 
+    /**
+     * Current lock wait timeout in seconds.
+     */
+    private volatile Duration currentLockWaitTimeout;
+
+    /**
+     * Session lock wait timeout in seconds.
+     */
+    private volatile Duration sessionLockWaitTimeout;
+
     /**
      * Assume that the auto commit is always turned on, it will be set after handshake V10 request message, or OK
      * message which means handshake V9 completed.
-     * <p>
-     * It would be updated multiple times, so {@code volatile} is required.
      */
     private volatile short serverStatuses = ServerStatuses.AUTO_COMMIT;
 
@@ -80,18 +118,50 @@ public final class ConnectionContext implements CodecContext {
     }
 
     /**
-     * Initializes this context.
+     * Initializes handshake information after connection is established.
      *
      * @param connectionId the connection identifier that is specified by server.
      * @param version      the server version.
      * @param capability   the connection capabilities.
      */
-    void init(int connectionId, ServerVersion version, Capability capability) {
+    void initHandshake(int connectionId, ServerVersion version, Capability capability) {
         this.connectionId = connectionId;
         this.serverVersion = version;
         this.capability = capability;
     }
 
+    /**
+     * Initializes session information after logged-in.
+     *
+     * @param prepareCache             the prepare cache.
+     * @param isolationLevel           the session isolation level.
+     * @param lockWaitTimeoutSupported if the server supports lock wait timeout.
+     * @param lockWaitTimeout          the lock wait timeout.
+     * @param product                  the server product name.
+     * @param timeZone                 the server timezone.
+     */
+    void initSession(
+        PrepareCache prepareCache,
+        IsolationLevel isolationLevel,
+        boolean lockWaitTimeoutSupported,
+        Duration lockWaitTimeout,
+        @Nullable String product,
+        @Nullable ZoneId timeZone
+    ) {
+        this.prepareCache = prepareCache;
+        this.currentIsolationLevel = this.sessionIsolationLevel = isolationLevel;
+        this.lockWaitTimeoutSupported = lockWaitTimeoutSupported;
+        this.currentLockWaitTimeout = this.sessionLockWaitTimeout = lockWaitTimeout;
+        this.product = product == null ? "Unknown" : product;
+
+        if (timeZone != null) {
+            if (isTimeZoneInitialized()) {
+                throw new IllegalStateException("Connection timezone have been initialized");
+            }
+            this.timeZone = timeZone;
+        }
+    }
+
     /**
      * Get the connection identifier that is specified by server.
      *
@@ -128,6 +198,14 @@ public ZoneId getTimeZone() {
         return timeZone;
     }
 
+    String getProduct() {
+        return product;
+    }
+
+    PrepareCache getPrepareCache() {
+        return prepareCache;
+    }
+
     boolean isTimeZoneInitialized() {
         return timeZone != null;
     }
@@ -138,13 +216,6 @@ public boolean isMariaDb() {
         return (capability != null && capability.isMariaDb()) || serverVersion.isMariaDb();
     }
 
-    void initTimeZone(ZoneId timeZone) {
-        if (isTimeZoneInitialized()) {
-            throw new IllegalStateException("Connection timezone have been initialized");
-        }
-        this.timeZone = timeZone;
-    }
-
     @Override
     public ZeroDateOption getZeroDateOption() {
         return zeroDateOption;
@@ -170,19 +241,23 @@ public int getLocalInfileBufferSize() {
     }
 
     /**
-     * Checks if the server supports lock wait timeout.
+     * Checks if the server supports InnoDB lock wait timeout.
      *
-     * @return if the server supports lock wait timeout.
+     * @return if the server supports InnoDB lock wait timeout.
      */
     public boolean isLockWaitTimeoutSupported() {
         return lockWaitTimeoutSupported;
     }
 
     /**
-     * Enables lock wait timeout supported when loading session variables.
+     * Checks if the server supports statement timeout.
+     *
+     * @return if the server supports statement timeout.
      */
-    void enableLockWaitTimeoutSupported() {
-        this.lockWaitTimeoutSupported = true;
+    public boolean isStatementTimeoutSupported() {
+        boolean isMariaDb = isMariaDb();
+        return (isMariaDb && serverVersion.isGreaterThanOrEqualTo(MARIA_10_1_1)) ||
+            (!isMariaDb && serverVersion.isGreaterThanOrEqualTo(MYSQL_5_7_4));
     }
 
     /**
@@ -202,4 +277,56 @@ public short getServerStatuses() {
     public void setServerStatuses(short serverStatuses) {
         this.serverStatuses = serverStatuses;
     }
+
+    IsolationLevel getCurrentIsolationLevel() {
+        return currentIsolationLevel;
+    }
+
+    void setCurrentIsolationLevel(IsolationLevel isolationLevel) {
+        this.currentIsolationLevel = isolationLevel;
+    }
+
+    void resetCurrentIsolationLevel() {
+        this.currentIsolationLevel = this.sessionIsolationLevel;
+    }
+
+    IsolationLevel getSessionIsolationLevel() {
+        return sessionIsolationLevel;
+    }
+
+    void setSessionIsolationLevel(IsolationLevel isolationLevel) {
+        this.sessionIsolationLevel = isolationLevel;
+    }
+
+    void setCurrentLockWaitTimeout(Duration timeoutSeconds) {
+        this.currentLockWaitTimeout = timeoutSeconds;
+    }
+
+    void resetCurrentLockWaitTimeout() {
+        this.currentLockWaitTimeout = this.sessionLockWaitTimeout;
+    }
+
+    boolean isLockWaitTimeoutChanged() {
+        return currentLockWaitTimeout != sessionLockWaitTimeout;
+    }
+
+    Duration getSessionLockWaitTimeout() {
+        return sessionLockWaitTimeout;
+    }
+
+    void setAllLockWaitTimeout(Duration timeoutSeconds) {
+        this.currentLockWaitTimeout = this.sessionLockWaitTimeout = timeoutSeconds;
+    }
+
+    boolean isInTransaction() {
+        return (serverStatuses & ServerStatuses.IN_TRANSACTION) != 0;
+    }
+
+    boolean isAutoCommit() {
+        // Within transaction, autocommit remains disabled until end the transaction with COMMIT or ROLLBACK.
+        // The autocommit mode then reverts to its previous state.
+        short serverStatuses = this.serverStatuses;
+        return (serverStatuses & ServerStatuses.IN_TRANSACTION) == 0 &&
+            (serverStatuses & ServerStatuses.AUTO_COMMIT) != 0;
+    }
 }