LP 448319 : Provide a Resource Property for addons

2 files changed, 73 insertions, 4 deletions

diff --git a/tutorius/constraints.py b/tutorius/constraints.py
index 519bce8..cd71167 100644
--- a/tutorius/constraints.py
+++ b/tutorius/constraints.py
@@ -24,6 +24,8 @@ for some properties.
 
 # For the File Constraint
 import os
+# For the Resource Constraint
+import re
 
 class ConstraintException(Exception):
     """
@@ -214,3 +216,40 @@ class FileConstraint(Constraint):
             raise FileConstraintError("Non-existing file : %s"%value)
         return
     
+class ResourceConstraintError(ConstraintException):
+    pass
+
+class ResourceConstraint(Constraint):
+    """
+    Ensures that the value is looking like a resource name, like
+    <filename>_<GUID>[.<extension>]. We are not validating that this is a
+    valid resource for the reason that the property does not have any notion
+    of tutorial guid.
+
+    TODO : Find a way to properly validate resources by looking them up in the
+            Vault.
+    """
+    
+    # Regular expression to parse a resource-like name
+    resource_regexp_text = "(.+)_([a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12})(\..*)?$"
+    resource_regexp = re.compile(resource_regexp_text)
+    
+    def validate(self, value):
+        # TODO : Validate that we will not use an empty resource or if we can
+        # have transitory resource names
+        if value is None:
+            raise ResourceConstraintError("Resource not allowed to have a null value!")
+
+        # Special case : We allow the empty resource name for now
+        if value == "":
+            return value
+
+        # Attempt to see if the value has a resource name inside it
+        match = self.resource_regexp.search(value)
+
+        # If there was no match on the reg exp
+        if not match:
+            raise ResourceConstraintError("Resource name does not seem to be valid : %s" % value)
+
+        # If the name matched, then the value is _PROBABLY_ good
+        return value
diff --git a/tutorius/properties.py b/tutorius/properties.py
index 5422532..ba3c211 100644
--- a/tutorius/properties.py
+++ b/tutorius/properties.py
@@ -24,7 +24,8 @@ from copy import copy, deepcopy
 from .constraints import Constraint, \
         UpperLimitConstraint, LowerLimitConstraint, \
         MaxSizeConstraint, MinSizeConstraint, \
-        ColorConstraint, FileConstraint, BooleanConstraint, EnumConstraint
+        ColorConstraint, FileConstraint, BooleanConstraint, EnumConstraint, \
+        ResourceConstraint
 
 class TPropContainer(object):
     """
@@ -261,8 +262,6 @@ class TFileProperty(TutoriusProperty):
         
         For now, the path may be relative or absolute, as long as it exists on
         the local machine.
-        TODO : Make sure that we have a file scheme that supports distribution
-        on other computers (LP 355197)
         """
         TutoriusProperty.__init__(self)
         
@@ -351,7 +350,7 @@ class TEventType(TutoriusProperty):
 
 class TAddonListProperty(TutoriusProperty):
     """
-    Reprensents an embedded tutorius Addon List Component.
+    Represents an embedded tutorius Addon List Component.
     See TAddonProperty
     """
     def __init__(self):
@@ -367,3 +366,34 @@ class TAddonListProperty(TutoriusProperty):
             return value
         raise ValueError("Value proposed to TAddonListProperty is not a list")
 
+class TResourceProperty(TutoriusProperty):
+    """
+    Represents a resource in the tutorial. A resource is a file with a specific
+    name that exists under the tutorials folder. It is distributed alongside the
+    tutorial itself.
+
+    When the system encounters a resource, it knows that it refers to a file in
+    the resource folder and that it should translate this resource name to an
+    absolute file name before it is executed.
+
+    E.g. An image is added to a tutorial in an action. On doing so, the creator
+        adds a resource to the tutorial, then saves its name in the resource
+        property of that action. When this tutorial is executed, the Engine
+        replaces all the TResourceProperties inside the action by their equivalent
+        TFileProperties with absolute paths, so that they can be used on any
+        machine.
+    """
+    def __init__(self, resource_name=""):
+        """
+        Creates a new resource pointing to an existing resource.
+        
+        @param resource_name The file name of the resource (should be only the 
+                            file name itself, no directory information)
+        """
+        TutoriusProperty.__init__(self)
+        self.type = "resource"
+
+        self.resource_cons = ResourceConstraint()
+
+        self.default = self.validate("")
+