Use UUID instead of int for rebase editor handler

The handler is used to communicate between the rebase editor process
and main IDEA process.

It is more safe to use UUID to prevent malicious code to access IDEA
process through XML RPC (although int was chosen randomly).

It is also more consistent with ssh/http handlers, which use UUIDs
since 63ad820.

plugins/git4idea/src/git4idea/rebase/GitInteractiveRebaseEditorHandler.java

@@ -28,6 +28,7 @@ import org.jetbrains.annotations.NotNull;
 
 import java.io.Closeable;
 import java.util.List;
+import java.util.UUID;
 
 /**
  * The handler for rebase editor request. The handler shows {@link git4idea.rebase.GitRebaseEditor}
@@ -58,7 +59,7 @@ public class GitInteractiveRebaseEditorHandler implements Closeable, GitRebaseEd
   /**
    * The handler number
    */
-  private final int myHandlerNo;
+  @NotNull private final UUID myHandlerNo;
   /**
    * If true, the handler has been closed
    */
@@ -197,7 +198,8 @@ public class GitInteractiveRebaseEditorHandler implements Closeable, GitRebaseEd
   /**
    * @return the handler number
    */
-  public int getHandlerNo() {
+  @NotNull
+  public UUID getHandlerNo() {
     return myHandlerNo;
   }
 

plugins/git4idea/src/git4idea/rebase/GitRebaseEditorMain.java

@@ -74,25 +74,17 @@ public class GitRebaseEditorMain {
       System.exit(ERROR_EXIT_CODE);
       return;
     }
-    final String handlerValue = System.getenv(IDEA_REBASE_HANDER_NO);
-    if (handlerValue == null) {
+    String handlerId = System.getenv(IDEA_REBASE_HANDER_NO);
+    if (handlerId == null) {
       System.err.println("Handler no is not specified");
       System.exit(ERROR_EXIT_CODE);
     }
-    int handler;
-    try {
-      handler = Integer.parseInt(handlerValue);
-    }
-    catch (NumberFormatException ex) {
-      System.err.println("Invalid handler number: " + handlerValue);
-      System.exit(ERROR_EXIT_CODE);
-      return;
-    }
+
     String file = args[1];
     try {
       XmlRpcClientLite client = new XmlRpcClientLite("127.0.0.1", port);
       Vector<Object> params = new Vector<>();
-      params.add(handler);
+      params.add(handlerId);
       if (System.getProperty("os.name").toLowerCase().startsWith("windows") && file.startsWith(CYGDRIVE_PREFIX)) {
         int p = CYGDRIVE_PREFIX.length();
         file = file.substring(p, p + 1) + ":" + file.substring(p + 1);

plugins/git4idea/src/git4idea/rebase/GitRebaseEditorService.java

@@ -17,9 +17,9 @@ package git4idea.rebase;
 
 import com.intellij.ide.XmlRpcServer;
 import com.intellij.openapi.components.ServiceManager;
+import com.intellij.util.containers.ContainerUtil;
 import git4idea.commands.GitCommand;
 import git4idea.commands.GitLineHandler;
-import gnu.trove.THashMap;
 import org.apache.commons.codec.DecoderException;
 import org.apache.xmlrpc.XmlRpcClientLite;
 import org.jetbrains.annotations.NonNls;
@@ -27,9 +27,8 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.git4idea.util.ScriptGenerator;
 import org.jetbrains.ide.BuiltInServerManager;
 
-import java.security.SecureRandom;
 import java.util.Map;
-import java.util.Random;
+import java.util.UUID;
 
 /**
  * The service that generates editor script for
@@ -46,15 +45,11 @@ public class GitRebaseEditorService {
   /**
    * The handlers to use
    */
-  private final Map<Integer, GitRebaseEditorHandler> myHandlers = new THashMap<>();
+  private final Map<UUID, GitRebaseEditorHandler> myHandlers = ContainerUtil.newHashMap();
   /**
    * The lock for the handlers
    */
   private final Object myHandlersLock = new Object();
-  /**
-   * Random number generator
-   */
-  private static final Random oursRandom = new SecureRandom();
   /**
    * The prefix for rebase editors
    */
@@ -103,33 +98,22 @@ public class GitRebaseEditorService {
    * @param handler the handler to register
    * @return the handler identifier
    */
-  public int registerHandler(GitRebaseEditorHandler handler) {
+  @NotNull
+  public UUID registerHandler(@NotNull GitRebaseEditorHandler handler) {
     addInternalHandler();
-    Integer rc = null;
     synchronized (myHandlersLock) {
-      for (int i = Integer.MAX_VALUE; i > 0; i--) {
-        int code = Math.abs(oursRandom.nextInt());
-        // note that code might still be negative at this point if it is Integer.MIN_VALUE.
-        if (code > 0 && !myHandlers.containsKey(code)) {
-          rc = code;
-          break;
-        }
-      }
-      if (rc == null) {
-        throw new IllegalStateException("There is a problem with random number allocation");
-      }
-      myHandlers.put(rc, handler);
+      UUID key = UUID.randomUUID();
+      myHandlers.put(key, handler);
+      return key;
     }
-    return rc;
   }
 
-
   /**
    * Unregister handler
    *
    * @param handlerNo the handler number.
    */
-  public void unregisterHandler(final int handlerNo) {
+  public void unregisterHandler(@NotNull UUID handlerNo) {
     synchronized (myHandlersLock) {
       if (myHandlers.remove(handlerNo) == null) {
         throw new IllegalStateException("The handler " + handlerNo + " has been already removed");
@@ -143,7 +127,7 @@ public class GitRebaseEditorService {
    * @param handlerNo the handler number.
    */
   @NotNull
-  GitRebaseEditorHandler getHandler(final int handlerNo) {
+  GitRebaseEditorHandler getHandler(@NotNull UUID handlerNo) {
     synchronized (myHandlersLock) {
       GitRebaseEditorHandler h = myHandlers.get(handlerNo);
       if (h == null) {
@@ -159,9 +143,9 @@ public class GitRebaseEditorService {
    * @param h        the handler to configure
    * @param editorNo the editor number
    */
-  public void configureHandler(GitLineHandler h, int editorNo) {
+  public void configureHandler(GitLineHandler h, @NotNull UUID editorNo) {
     h.setEnvironment(GitCommand.GIT_EDITOR_ENV, getEditorCommand());
-    h.setEnvironment(GitRebaseEditorMain.IDEA_REBASE_HANDER_NO, Integer.toString(editorNo));
+    h.setEnvironment(GitRebaseEditorMain.IDEA_REBASE_HANDER_NO, editorNo.toString());
   }
 
 
@@ -177,8 +161,8 @@ public class GitRebaseEditorService {
      * @return exit code
      */
     @SuppressWarnings({"UnusedDeclaration"})
-    public int editCommits(int handlerNo, String path) {
-      GitRebaseEditorHandler editor = getHandler(handlerNo);
+    public int editCommits(@NotNull String handlerNo, String path) {
+      GitRebaseEditorHandler editor = getHandler(UUID.fromString(handlerNo));
       return editor.editCommits(path);
     }
   }

plugins/git4idea/src/git4idea/rebase/GitRebaser.java

@@ -163,7 +163,7 @@ public class GitRebaser {
     GitRebaseEditorService rebaseEditorService = GitRebaseEditorService.getInstance();
     // TODO If interactive rebase with commit rewording was invoked, this should take the reworded message
     GitRebaser.TrivialEditor editor = new GitRebaser.TrivialEditor(rebaseEditorService, myProject, root, rh);
-    Integer rebaseEditorNo = editor.getHandlerNo();
+    UUID rebaseEditorNo = editor.getHandlerNo();
     rebaseEditorService.configureHandler(rh, rebaseEditorNo);
   }
 
@@ -196,7 +196,7 @@ public class GitRebaser {
 
     final GitLineHandler h = new GitLineHandler(myProject, root, GitCommand.REBASE);
     h.setStdoutSuppressed(false);
-    Integer rebaseEditorNo = null;
+    UUID rebaseEditorNo = null;
     GitRebaseEditorService rebaseEditorService = GitRebaseEditorService.getInstance();
     try {
       h.addParameters("-i", "-m", "-v");