Method rename

src/generic/key_value_filesystem.ts:751–867

(oldPath: string, newPath: string, cb: BFSOneArgCallback)

  }

  public rename(oldPath: string, newPath: string, cb: BFSOneArgCallback): void {
    const tx = this.store.beginTransaction('readwrite');
    const oldParent = path.dirname(oldPath), oldName = path.basename(oldPath);
    const newParent = path.dirname(newPath), newName = path.basename(newPath);
    const inodes: { [path: string]: Inode } = {};
    const lists: {
      [path: string]: { [file: string]: string }
    } = {};
    let errorOccurred: boolean = false;

    // Invariant: Can't move a folder inside itself.
    // This funny little hack ensures that the check passes only if oldPath
    // is a subpath of newParent. We append '/' to avoid matching folders that
    // are a substring of the bottom-most folder in the path.
    if ((newParent + '/').indexOf(oldPath + '/') === 0) {
      return cb(new ApiError(ErrorCode.EBUSY, oldParent));
    }

    /**
     * Responsible for Phase 2 of the rename operation: Modifying and
     * committing the directory listings. Called once we have successfully
     * retrieved both the old and new parent's inodes and listings.
     */
    const theOleSwitcharoo = (): void => {
      // Sanity check: Ensure both paths are present, and no error has occurred.
      if (errorOccurred || !lists.hasOwnProperty(oldParent) || !lists.hasOwnProperty(newParent)) {
        return;
      }
      const oldParentList = lists[oldParent], oldParentINode = inodes[oldParent],
        newParentList = lists[newParent], newParentINode = inodes[newParent];

      // Delete file from old parent.
      if (!oldParentList[oldName]) {
        cb(ApiError.ENOENT(oldPath));
      } else {
        const fileId = oldParentList[oldName];
        delete oldParentList[oldName];

        // Finishes off the renaming process by adding the file to the new
        // parent.
        const completeRename = () => {
          newParentList[newName] = fileId;
          // Commit old parent's list.
          tx.put(oldParentINode.id, Buffer.from(JSON.stringify(oldParentList)), true, (e: ApiError) => {
            if (noErrorTx(e, tx, cb)) {
              if (oldParent === newParent) {
                // DONE!
                tx.commit(cb);
              } else {
                // Commit new parent's list.
                tx.put(newParentINode.id, Buffer.from(JSON.stringify(newParentList)), true, (e: ApiError) => {
                  if (noErrorTx(e, tx, cb)) {
                    tx.commit(cb);
                  }
                });
              }
            }
          });