feat: parse the sdi page

innodb-java-reader/src/main/java/com/alibaba/innodb/java/reader/page/SdiPage.java

@@ -3,15 +3,75 @@
  */
 package com.alibaba.innodb.java.reader.page;
 
+import com.alibaba.innodb.java.reader.exception.ReaderException;
+import com.alibaba.innodb.java.reader.page.index.*;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+
+import static com.alibaba.innodb.java.reader.Constants.BYTES_OF_INFIMUM;
+import static com.alibaba.innodb.java.reader.Constants.BYTES_OF_SUPREMUM;
+import static com.alibaba.innodb.java.reader.SizeOf.*;
+import static com.alibaba.innodb.java.reader.SizeOf.SIZE_OF_PAGE_DIR_SLOT;
+import static com.google.common.base.Preconditions.checkState;
+
 /**
  * Since MySQL8.0, there is SDI, a.k.a Serialized Dictionary Information(SDI).
  *
  * @author xu.zx
  */
 public class SdiPage extends AbstractPage {
 
+  private IndexHeader indexHeader;
+
+  private FsegHeader fsegHeader;
+
+  private RecordHeader infimumHeader;
+
+  private RecordHeader supremumHeader;
+
+  private int[] dirSlots;
+
+  private List<SdiRecord> sdiRecordList = new LinkedList<>();
+
   public SdiPage(InnerPage innerPage) {
     super(innerPage);
+    this.indexHeader = IndexHeader.fromSlice(sliceInput);
+    if (this.indexHeader.getFormat() != PageFormat.COMPACT) {
+      throw new ReaderException("only support COMPACT format");
+    }
+    this.fsegHeader = FsegHeader.fromSlice(sliceInput);
+
+    this.infimumHeader = RecordHeader.fromSlice(sliceInput);
+    checkState(Arrays.equals(sliceInput.readByteArray(SIZE_OF_MUM_RECORD), BYTES_OF_INFIMUM));
+
+    this.supremumHeader = RecordHeader.fromSlice(sliceInput);
+    checkState(Arrays.equals(sliceInput.readByteArray(SIZE_OF_MUM_RECORD), BYTES_OF_SUPREMUM));
+
+    int dirSlotNum = this.indexHeader.getNumOfDirSlots();
+    dirSlots = new int[dirSlotNum];
+    sliceInput.setPosition(SIZE_OF_PAGE - SIZE_OF_FIL_TRAILER - dirSlotNum * SIZE_OF_PAGE_DIR_SLOT);
+    for (int i = 0; i < dirSlotNum; i++) {
+      dirSlots[dirSlotNum - i - 1] = sliceInput.readUnsignedShort();
+    }
+    sliceInput.setPosition(dirSlots[0]);
+    RecordHeader recordHeader = null;
+    while (true) {
+      sliceInput.decrPosition(SIZE_OF_REC_HEADER);
+      recordHeader = RecordHeader.fromSlice(sliceInput);
+      if (recordHeader.getRecordType() == RecordType.INFIMUM) {
+        sliceInput.setPosition(sliceInput.position() + recordHeader.getNextRecOffset());
+        continue;
+      }
+      if (recordHeader.getRecordType() == RecordType.SUPREMUM) {
+        break;
+      }
+      int pos = sliceInput.position();
+      SdiRecord record = new SdiRecord(sliceInput, recordHeader);
+      this.sdiRecordList.add(record);
+      sliceInput.setPosition(pos + recordHeader.getNextRecOffset());
+    }
   }
 
 }

innodb-java-reader/src/main/java/com/alibaba/innodb/java/reader/page/index/SdiRecord.java

@@ -0,0 +1,80 @@
+package com.alibaba.innodb.java.reader.page.index;
+
+import com.alibaba.innodb.java.reader.util.SliceInput;
+import com.alibaba.innodb.java.reader.util.ZlibUtil;
+import lombok.Data;
+
+import java.nio.charset.StandardCharsets;
+
+import static com.alibaba.innodb.java.reader.SizeOf.SIZE_OF_REC_HEADER;
+
+/**
+ * @author jie xu
+ * @description
+ * @created 2020/12/21
+ **/
+@Data
+public class SdiRecord {
+
+  private int contentLength;
+
+  private RecordHeader recordHeader;
+
+  private int sdiType;
+
+  private long sdiId;
+
+  private long sdiTransId;
+
+  private int unzipLength;
+
+  private int zipLength;
+
+  private String content;
+
+  public SdiRecord(SliceInput sliceInput, RecordHeader recordHeader) {
+    this.recordHeader = recordHeader;
+    int position = sliceInput.position();
+    this.contentLength = parseContentLength(sliceInput);
+    sliceInput.setPosition(position);
+    this.sdiType = sliceInput.readInt();
+    this.sdiId = sliceInput.readLong();
+    this.sdiTransId = sliceInput.read6BytesInt();
+    //skip rollBackRef
+    sliceInput.setPosition(sliceInput.position() + 7);
+    this.unzipLength = sliceInput.readInt();
+    this.zipLength = sliceInput.readInt();
+    if (this.contentLength != zipLength && this.contentLength != unzipLength) {
+      throw new RuntimeException("sdi record parse error!");
+    }
+    byte[] buffer = new byte[this.contentLength];
+    sliceInput.readBytes(buffer);
+    if (this.contentLength == zipLength) {
+      buffer = ZlibUtil.decompress(buffer);
+    }
+    this.content = new String(buffer, 0, buffer.length, StandardCharsets.US_ASCII);
+    sliceInput.setPosition(position);
+  }
+
+  private int parseContentLength(SliceInput sliceInput) {
+    int resu = 0;
+    sliceInput.decrPosition(SIZE_OF_REC_HEADER + 1);
+    int first = sliceInput.readUnsignedByte();
+    if ((first & 0x80) != 0) {
+      resu = (first & 0x3f) << 8;
+      if ((first & 0x40) != 0x00) {
+        //todo big data length, read from overflowPage (BLOB page?)
+        throw new RuntimeException("unsupported record length");
+      } else {
+        sliceInput.decrPosition(2);
+        int second = sliceInput.readUnsignedByte();
+        sliceInput.readUnsignedByte();
+        resu += second;
+      }
+    } else {
+      resu = first;
+    }
+    return resu;
+  }
+
+}

innodb-java-reader/src/main/java/com/alibaba/innodb/java/reader/util/ZlibUtil.java

@@ -0,0 +1,42 @@
+package com.alibaba.innodb.java.reader.util;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.zip.Inflater;
+
+/**
+ * @author jie xu
+ * @description
+ * @created 2020/12/22
+ **/
+public class ZlibUtil {
+  public static byte[] decompress(byte[] data) {
+    byte[] output = new byte[0];
+
+    Inflater decompresser = new Inflater();
+    decompresser.reset();
+    decompresser.setInput(data);
+
+    ByteArrayOutputStream o = new ByteArrayOutputStream(data.length);
+    try {
+      byte[] buf = new byte[1024];
+      while (!decompresser.finished()) {
+        int i = decompresser.inflate(buf);
+        o.write(buf, 0, i);
+      }
+      output = o.toByteArray();
+    } catch (Exception e) {
+      output = data;
+      e.printStackTrace();
+    } finally {
+      try {
+        o.close();
+      } catch (IOException e) {
+        e.printStackTrace();
+      }
+    }
+
+    decompresser.end();
+    return output;
+  }
+}