Sharing org.simantics.acorn for everyone to use

[simantics/platform.git] / bundles / org.simantics.acorn / src / org / simantics / db / javacore / HeadState.java

diff --git a/bundles/org.simantics.acorn/src/org/simantics/db/javacore/HeadState.java b/bundles/org.simantics.acorn/src/org/simantics/db/javacore/HeadState.java
new file mode 100644 (file)
index 0000000..5a96be2
--- /dev/null
+++ b/bundles/org.simantics.acorn/src/org/simantics/db/javacore/HeadState.java
@@ -0,0 +1,73 @@
+package org.simantics.db.javacore;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.Serializable;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.ArrayList;
+import java.util.Arrays;
+
+import org.simantics.acorn.InvalidHeadStateException;
+
+public class HeadState implements Serializable {
+
+    private static final long serialVersionUID = -4135031566499790077L;
+
+    public int headChangeSetId = 0;
+    public long transactionId = 1;
+    public long reservedIds = 3;
+
+    public ArrayList<String> clusters = new ArrayList<>();
+    public ArrayList<String> files = new ArrayList<>();
+    public ArrayList<String> stream = new ArrayList<>();
+    public ArrayList<String> cs = new ArrayList<>();
+//    public ArrayList<String> ccs = new ArrayList<String>();
+
+    public static HeadState load(Path directory) throws InvalidHeadStateException {
+        Path f = directory.resolve("head.state");
+        try {
+            byte[] bytes = Files.readAllBytes(f);
+            MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
+            int digestLength = sha1.getDigestLength();
+            sha1.update(bytes, digestLength, bytes.length - digestLength);
+            byte[] newChecksum = sha1.digest();
+            if (!Arrays.equals(newChecksum, Arrays.copyOfRange(bytes, 0, digestLength))) {
+                throw new InvalidHeadStateException(
+                        "Checksum " + Arrays.toString(newChecksum) + " does not match excpected "
+                                + Arrays.toString(Arrays.copyOfRange(bytes, 0, digestLength)) + " for " + f.toAbsolutePath());
+            }
+            try (ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(bytes, digestLength, bytes.length - digestLength))) {
+                HeadState state = (HeadState) ois.readObject();
+                return state;
+            }
+        } catch (IOException i) {
+            return new HeadState();
+        } catch (ClassNotFoundException c) {
+//            throw new Error("HeadState class not found", c);
+            return new HeadState();
+        } catch (NoSuchAlgorithmException e) {
+            throw new Error("SHA-1 Algorithm not found", e);
+        }
+    }
+
+    public static void validateHeadStateIntegrity(Path headState) throws InvalidHeadStateException, IOException {
+        try {
+            byte[] bytes = Files.readAllBytes(headState);
+            MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
+            int digestLength = sha1.getDigestLength();
+            sha1.update(bytes, digestLength, bytes.length - digestLength);
+            byte[] newChecksum = sha1.digest();
+            if (!Arrays.equals(newChecksum, Arrays.copyOfRange(bytes, 0, digestLength))) {
+                throw new InvalidHeadStateException(
+                        "Checksum " + Arrays.toString(newChecksum) + " does not match excpected "
+                                + Arrays.toString(Arrays.copyOfRange(bytes, 0, digestLength)) + " for " + headState.toAbsolutePath());
+            }
+        } catch (NoSuchAlgorithmException e) {
+            throw new Error("SHA-1 digest not found, should not happen", e);
+        }
+    }
+}