/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
    * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.acegisecurity.acls.domain;
  
  import org.acegisecurity.acls.AccessControlEntry;
  import org.acegisecurity.acls.Acl;
  import org.acegisecurity.acls.AuditableAcl;
  import org.acegisecurity.acls.MutableAcl;
  import org.acegisecurity.acls.NotFoundException;
  import org.acegisecurity.acls.OwnershipAcl;
  import org.acegisecurity.acls.Permission;
  import org.acegisecurity.acls.UnloadedSidException;
  import org.acegisecurity.acls.objectidentity.ObjectIdentity;
  import org.acegisecurity.acls.sid.Sid;
  
  import org.springframework.util.Assert;
  
  import java.io.Serializable;
  
  import java.util.Iterator;
  import java.util.List;
  import java.util.Vector;
  
  
  /**
   * Base implementation of <code>Acl</code>.
   *
   * @author Ben Alex
   * @version $Id
   */
  public class AclImpl implements Acl, MutableAcl, AuditableAcl, OwnershipAcl {
      //~ Instance fields ================================================================================================
  
      private Acl parentAcl;
      private AclAuthorizationStrategy aclAuthorizationStrategy;
      private AuditLogger auditLogger;
      private List aces = new Vector();
      private ObjectIdentity objectIdentity;
      private Serializable id;
      private Sid owner; // OwnershipAcl
      private Sid[] loadedSids = null; // includes all SIDs the WHERE clause covered, even if there was no ACE for a SID
      private boolean entriesInheriting = true;
  
      //~ Constructors ===================================================================================================
  
  /**
       * Minimal constructor, which should be used {@link
       * org.acegisecurity.acls.MutableAclService#createAcl(ObjectIdentity)}.
       *
       * @param objectIdentity the object identity this ACL relates to (required)
       * @param id the primary key assigned to this ACL (required)
       * @param aclAuthorizationStrategy authorization strategy (required)
       * @param auditLogger audit logger (required)
       */
      public AclImpl(ObjectIdentity objectIdentity, Serializable id, AclAuthorizationStrategy aclAuthorizationStrategy,
          AuditLogger auditLogger) {
          Assert.notNull(objectIdentity, "Object Identity required");
          Assert.notNull(id, "Id required");
          Assert.notNull(aclAuthorizationStrategy, "AclAuthorizationStrategy required");
          Assert.notNull(auditLogger, "AuditLogger required");
          this.objectIdentity = objectIdentity;
          this.id = id;
          this.aclAuthorizationStrategy = aclAuthorizationStrategy;
          this.auditLogger = auditLogger;
      }
  
  /**
       * Full constructor, which should be used by persistence tools that do not
       * provide field-level access features.
       *
       * @param objectIdentity the object identity this ACL relates to (required)
       * @param id the primary key assigned to this ACL (required)
       * @param aclAuthorizationStrategy authorization strategy (required)
       * @param auditLogger audit logger (required)
       * @param parentAcl the parent (may be <code>null</code>)
       * @param loadedSids the loaded SIDs if only a subset were loaded (may be
       *        <code>null</code>)
       * @param entriesInheriting if ACEs from the parent should inherit into
       *        this ACL
       * @param owner the owner (required)
       */
      public AclImpl(ObjectIdentity objectIdentity, Serializable id, AclAuthorizationStrategy aclAuthorizationStrategy,
          AuditLogger auditLogger, Acl parentAcl, Sid[] loadedSids, boolean entriesInheriting, Sid owner) {
          Assert.notNull(objectIdentity, "Object Identity required");
          Assert.notNull(id, "Id required");
          Assert.notNull(aclAuthorizationStrategy, "AclAuthorizationStrategy required");
          Assert.notNull(owner, "Owner required");
         Assert.notNull(auditLogger, "AuditLogger required");
         this.objectIdentity = objectIdentity;
         this.id = id;
         this.aclAuthorizationStrategy = aclAuthorizationStrategy;
         this.auditLogger = auditLogger;
         this.parentAcl = parentAcl; // may be null
         this.loadedSids = loadedSids; // may be null
         this.entriesInheriting = entriesInheriting;
         this.owner = owner;
     }
 
 /**
      * Private no-argument constructor for use by reflection-based persistence
      * tools along with field-level access.
      */
     private AclImpl() {}
 
     //~ Methods ========================================================================================================
 
     public void deleteAce(Serializable aceId) throws NotFoundException {
         aclAuthorizationStrategy.securityCheck(this, AclAuthorizationStrategy.CHANGE_GENERAL);
 
         synchronized (aces) {
             int offset = findAceOffset(aceId);
 
             if (offset == -1) {
                 throw new NotFoundException("Requested ACE ID not found");
             }
 
             this.aces.remove(offset);
         }
     }
 
     private int findAceOffset(Serializable aceId) {
         Assert.notNull(aceId, "ACE ID is required");
 
         synchronized (aces) {
             for (int i = 0; i < aces.size(); i++) {
                 AccessControlEntry ace = (AccessControlEntry) aces.get(i);
 
                 if (ace.getId().equals(aceId)) {
                     return i;
                 }
             }
         }
 
         return -1;
     }
 
     public AccessControlEntry[] getEntries() {
         // Can safely return AccessControlEntry directly, as they're immutable outside the ACL package
         return (AccessControlEntry[]) aces.toArray(new AccessControlEntry[] {});
     }
 
     public Serializable getId() {
         return this.id;
     }
 
     public ObjectIdentity getObjectIdentity() {
         return objectIdentity;
     }
 
     public Sid getOwner() {
         return this.owner;
     }
 
     public Acl getParentAcl() {
         return parentAcl;
     }
 
     public void insertAce(Serializable afterAceId, Permission permission, Sid sid, boolean granting)
         throws NotFoundException {
         aclAuthorizationStrategy.securityCheck(this, AclAuthorizationStrategy.CHANGE_GENERAL);
         Assert.notNull(permission, "Permission required");
         Assert.notNull(sid, "Sid required");
 
         AccessControlEntryImpl ace = new AccessControlEntryImpl(null, this, sid, permission, granting, false, false);
 
         synchronized (aces) {
             if (afterAceId != null) {
                 int offset = findAceOffset(afterAceId);
 
                 if (offset == -1) {
                     throw new NotFoundException("Requested ACE ID not found");
                 }
 
                 this.aces.add(offset + 1, ace);
             } else {
                 this.aces.add(ace);
             }
         }
     }
 
     public boolean isEntriesInheriting() {
         return entriesInheriting;
     }
 
     /**
      * Determines authorization.  The order of the <code>permission</code> and <code>sid</code> arguments is
      * <em>extremely important</em>! The method will iterate through each of the <code>permission</code>s in the order
      * specified. For each iteration, all of the <code>sid</code>s will be considered, again in the order they are
      * presented. A search will then be performed for the first {@link AccessControlEntry} object that directly
      * matches that <code>permission:sid</code> combination. When the <em>first full match</em> is found (ie an ACE
      * that has the SID currently being searched for and the exact permission bit mask being search for), the grant or
      * deny flag for that ACE will prevail. If the ACE specifies to grant access, the method will return
      * <code>true</code>. If the ACE specifies to deny access, the loop will stop and the next <code>permission</code>
      * iteration will be performed. If each permission indicates to deny access, the first deny ACE found will be
      * considered the reason for the failure (as it was the first match found, and is therefore the one most logically
      * requiring changes - although not always). If absolutely no matching ACE was found at all for any permission,
      * the parent ACL will be tried (provided that there is a parent and {@link #isEntriesInheriting()} is
      * <code>true</code>. The parent ACL will also scan its parent and so on. If ultimately no matching ACE is found,
      * a <code>NotFoundException</code> will be thrown and the caller will need to decide how to handle the permission
      * check. Similarly, if any of the SID arguments presented to the method were not loaded by the ACL,
      * <code>UnloadedSidException</code> will be thrown.
      *
      * @param permission the exact permissions to scan for (order is important)
      * @param sids the exact SIDs to scan for (order is important)
      * @param administrativeMode if <code>true</code> denotes the query is for administrative purposes and no auditing
      *        will be undertaken
      *
      * @return <code>true</code> if one of the permissions has been granted, <code>false</code> if one of the
      *         permissions has been specifically revoked
      *
      * @throws NotFoundException if an exact ACE for one of the permission bit masks and SID combination could not be
      *         found
      * @throws UnloadedSidException if the passed SIDs are unknown to this ACL because the ACL was only loaded for a
      *         subset of SIDs
      */
     public boolean isGranted(Permission[] permission, Sid[] sids, boolean administrativeMode)
         throws NotFoundException, UnloadedSidException {
         Assert.notEmpty(permission, "Permissions required");
         Assert.notEmpty(sids, "SIDs required");
 
         if (!this.isSidLoaded(sids)) {
             throw new UnloadedSidException("ACL was not loaded for one or more SID");
         }
 
         AccessControlEntry firstRejection = null;
 
         for (int i = 0; i < permission.length; i++) {
             for (int x = 0; x < sids.length; x++) {
                 // Attempt to find exact match for this permission mask and SID
                 Iterator acesIterator = aces.iterator();
                 boolean scanNextSid = true;
 
                 while (acesIterator.hasNext()) {
                     AccessControlEntry ace = (AccessControlEntry) acesIterator.next();
 
                     if ((ace.getPermission().getMask() == permission[i].getMask()) && ace.getSid().equals(sids[x])) {
                         // Found a matching ACE, so its authorization decision will prevail
                         if (ace.isGranting()) {
                             // Success
                             if (!administrativeMode) {
                                 auditLogger.logIfNeeded(true, ace);
                             }
 
                             return true;
                         } else {
                             // Failure for this permission, so stop search
                             // We will see if they have a different permission
                             // (this permission is 100% rejected for this SID)
                             if (firstRejection == null) {
                                 // Store first rejection for auditing reasons
                                 firstRejection = ace;
                             }
 
                             scanNextSid = false; // helps break the loop
 
                             break; // exit "aceIterator" while loop
                         }
                     }
                 }
 
                 if (!scanNextSid) {
                     break; // exit SID for loop (now try next permission)
                 }
             }
         }
 
         if (firstRejection != null) {
             // We found an ACE to reject the request at this point, as no
             // other ACEs were found that granted a different permission
             if (!administrativeMode) {
                 auditLogger.logIfNeeded(false, firstRejection);
             }
 
             return false;
         }
 
         // No matches have been found so far
         if (isEntriesInheriting() && (parentAcl != null)) {
             // We have a parent, so let them try to find a matching ACE
             return parentAcl.isGranted(permission, sids, false);
         } else {
             // We either have no parent, or we're the uppermost parent
             throw new NotFoundException("Unable to locate a matching ACE for passed permissions and SIDs");
         }
     }
 
     public boolean isSidLoaded(Sid[] sids) {
         // If loadedSides is null, this indicates all SIDs were loaded
         // Also return true if the caller didn't specify a SID to find
         if ((this.loadedSids == null) || (sids == null) || (sids.length == 0)) {
             return true;
         }
 
         // This ACL applies to a SID subset only. Iterate to check it applies.
         for (int i = 0; i < sids.length; i++) {
             boolean found = false;
 
             for (int y = 0; y < this.loadedSids.length; y++) {
                 if (sids[i].equals(this.loadedSids[y])) {
                     // this SID is OK
                     found = true;
 
                     break; // out of loadedSids for loop
                 }
             }
 
             if (!found) {
                 return false;
             }
         }
 
         return true;
     }
 
     public void setEntriesInheriting(boolean entriesInheriting) {
         aclAuthorizationStrategy.securityCheck(this, AclAuthorizationStrategy.CHANGE_GENERAL);
         this.entriesInheriting = entriesInheriting;
     }
 
     public void setOwner(Sid newOwner) {
         aclAuthorizationStrategy.securityCheck(this, AclAuthorizationStrategy.CHANGE_OWNERSHIP);
         Assert.notNull(newOwner, "Owner required");
         this.owner = newOwner;
     }
 
     public void setParent(Acl newParent) {
         aclAuthorizationStrategy.securityCheck(this, AclAuthorizationStrategy.CHANGE_GENERAL);
         Assert.notNull(newParent, "New Parent required");
         Assert.isTrue(!newParent.equals(this), "Cannot be the parent of yourself");
         this.parentAcl = newParent;
     }
 
     public String toString() {
         StringBuffer sb = new StringBuffer();
         sb.append("AclImpl[");
         sb.append("id: ").append(this.id).append("; ");
         sb.append("objectIdentity: ").append(this.objectIdentity).append("; ");
         sb.append("owner: ").append(this.owner).append("; ");
 
         Iterator iterator = this.aces.iterator();
         int count = 0;
 
         while (iterator.hasNext()) {
             count++;
 
             if (count == 1) {
                 sb.append("\r\n");
             }
 
             sb.append(iterator.next().toString()).append("\r\n");
         }
 
         if (count == 0) {
             sb.append("no ACEs; ");
         }
 
         sb.append("inheriting: ").append(this.entriesInheriting).append("; ");
         sb.append("parent: ").append((this.parentAcl == null) ? "Null" : this.parentAcl.getObjectIdentity().toString());
         sb.append("]");
 
         return sb.toString();
     }
 
     public void updateAce(Serializable aceId, Permission permission)
         throws NotFoundException {
         aclAuthorizationStrategy.securityCheck(this, AclAuthorizationStrategy.CHANGE_GENERAL);
 
         synchronized (aces) {
             int offset = findAceOffset(aceId);
 
             if (offset == 1) {
                 throw new NotFoundException("Requested ACE ID not found");
             }
 
             AccessControlEntryImpl ace = (AccessControlEntryImpl) aces.get(offset);
             ace.setPermission(permission);
         }
     }
 
     public void updateAuditing(Serializable aceId, boolean auditSuccess, boolean auditFailure) {
         aclAuthorizationStrategy.securityCheck(this, AclAuthorizationStrategy.CHANGE_AUDITING);
 
         synchronized (aces) {
             int offset = findAceOffset(aceId);
 
             if (offset == 1) {
                 throw new NotFoundException("Requested ACE ID not found");
             }
 
             AccessControlEntryImpl ace = (AccessControlEntryImpl) aces.get(offset);
             ace.setAuditSuccess(auditSuccess);
             ace.setAuditFailure(auditFailure);
         }
     }
 }