Merge pull request #1 from PixarAnimationStudios/master

Fix for hook manifest issue (AcademySoftwareFoundation#403)

docs/tutorials/write-a-hookscript.md

@@ -33,12 +33,13 @@ To create a new OTIO hook script, you need to create a file myhooks.py. Then add
             "OTIO_SCHEMA" : "HookScript.1",
             "name" : "example hook",
             "execution_scope" : "in process",
-            "filepath" : "example.py"
+            "filepath" : "myhooks.py"
         }
     ],
     "hooks" : {
         "pre_adapter_write" : ["example hook"],
-        "post_adapter_read" : []
+        "post_adapter_read" : [],
+        "post_media_linker" : []
     }
 }
 ```

opentimelineio/plugins/manifest.py

@@ -89,7 +89,7 @@ def __init__(self):
         self.source_files = []
 
         # hook system stuff
-        self.hooks = []
+        self.hooks = {}
         self.hook_scripts = []
 
     adapters = core.serializable_field(
@@ -109,7 +109,7 @@ def __init__(self):
     )
     hooks = core.serializable_field(
         "hooks",
-        type([]),
+        type({}),
         "Hooks that hooks scripts can be attached to."
     )
     hook_scripts = core.serializable_field(
@@ -127,11 +127,17 @@ def extend(self, another_manifest):
             self.adapters.extend(another_manifest.adapters)
             self.schemadefs.extend(another_manifest.schemadefs)
             self.media_linkers.extend(another_manifest.media_linkers)
+            self.hook_scripts.extend(another_manifest.hook_scripts)
+
+            for trigger_name, hooks in another_manifest.hooks.items():
+                if trigger_name in self.hooks:
+                    self.hooks[trigger_name].extend(hooks)
 
     def _update_plugin_source(self, path):
         """Track the source .json for a given adapter."""
 
-        for thing in (self.adapters + self.schemadefs + self.media_linkers):
+        for thing in (self.adapters + self.schemadefs
+                      + self.media_linkers + self.hook_scripts):
             thing._json_path = path
 
     def from_filepath(self, suffix):
@@ -217,8 +223,8 @@ def load_manifest():
                     plugin_manifest = plugin_entry_point.plugin_manifest()
                 except AttributeError:
                     if not pkg_resources.resource_exists(
-                        plugin.module_name,
-                        'plugin_manifest.json'
+                            plugin.module_name,
+                            'plugin_manifest.json'
                     ):
                         raise
                     manifest_stream = pkg_resources.resource_stream(