X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/045e3127cb48845c7d988d01488c055f02ae2ec3..9f1850a385ee8e0a011474de19ee6507b0b168f3:/services/api/app/models/link.rb

diff --git a/services/api/app/models/link.rb b/services/api/app/models/link.rb
index 83043a56d1..2eb6b88a0c 100644
--- a/services/api/app/models/link.rb
+++ b/services/api/app/models/link.rb
@@ -14,10 +14,15 @@ class Link < ArvadosModel
   validate :name_links_are_obsolete
   validate :permission_to_attach_to_objects
   before_update :restrict_alter_permissions
-  after_update :call_update_permissions
-  after_create :call_update_permissions
+  before_update :apply_max_overlapping_permissions
+  before_create :apply_max_overlapping_permissions
+  after_update :delete_overlapping_permissions
+  after_update :call_update_permissions, :if => Proc.new { @need_update_permissions }
+  after_create :call_update_permissions, :if => Proc.new { @need_update_permissions }
   before_destroy :clear_permissions
+  after_destroy :delete_overlapping_permissions
   after_destroy :check_permissions
+  before_save :check_need_update_permissions
 
   api_accessible :user, extend: :common do |t|
     t.add :tail_uuid
@@ -29,6 +34,58 @@ class Link < ArvadosModel
     t.add :properties
   end
 
+  PermLevel = {
+    'can_read' => 0,
+    'can_write' => 1,
+    'can_manage' => 2,
+  }
+
+  def apply_max_overlapping_permissions
+    return if self.link_class != 'permission' || !PermLevel[self.name]
+    Link.
+      lock. # select ... for update
+      where(link_class: 'permission',
+            tail_uuid: self.tail_uuid,
+            head_uuid: self.head_uuid,
+            name: PermLevel.keys).
+      where('uuid <> ?', self.uuid).each do |other|
+      if PermLevel[other.name] > PermLevel[self.name]
+        self.name = other.name
+      end
+    end
+  end
+
+  def delete_overlapping_permissions
+    return if self.link_class != 'permission'
+    redundant = nil
+    if PermLevel[self.name]
+      redundant = Link.
+                    lock. # select ... for update
+                    where(link_class: 'permission',
+                          tail_uuid: self.tail_uuid,
+                          head_uuid: self.head_uuid,
+                          name: PermLevel.keys).
+                    where('uuid <> ?', self.uuid)
+    elsif self.name == 'can_login' &&
+          self.properties.respond_to?(:has_key?) &&
+          self.properties.has_key?('username')
+      redundant = Link.
+                    lock. # select ... for update
+                    where(link_class: 'permission',
+                          tail_uuid: self.tail_uuid,
+                          head_uuid: self.head_uuid,
+                          name: 'can_login').
+                    where('properties @> ?', SafeJSON.dump({'username' => self.properties['username']})).
+                    where('uuid <> ?', self.uuid)
+    end
+    if redundant
+      redundant.each do |link|
+        link.clear_permissions
+      end
+      redundant.delete_all
+    end
+  end
+
   def head_kind
     if k = ArvadosModel::resource_class_for_uuid(head_uuid)
       k.kind
@@ -133,11 +190,13 @@ class Link < ArvadosModel
     'can_manage' => 3,
   }
 
+  def check_need_update_permissions
+    @need_update_permissions = self.link_class == 'permission' && (name != name_was || new_record?)
+  end
+
   def call_update_permissions
-    if self.link_class == 'permission'
       update_permissions tail_uuid, head_uuid, PERM_LEVEL[name], self.uuid
       current_user.forget_cached_group_perms
-    end
   end
 
   def clear_permissions