data: track: refactor inheritFromOriginalRelease

3 files changed, 108 insertions, 30 deletions

diff --git a/src/data/composite/things/track/index.js b/src/data/composite/things/track/index.js
index cc723a24..8959de9f 100644
--- a/src/data/composite/things/track/index.js
+++ b/src/data/composite/things/track/index.js
@@ -9,3 +9,4 @@ export {default as withContainingTrackSection} from './withContainingTrackSectio
 export {default as withHasUniqueCoverArt} from './withHasUniqueCoverArt.js';
 export {default as withOtherReleases} from './withOtherReleases.js';
 export {default as withPropertyFromAlbum} from './withPropertyFromAlbum.js';
+export {default as withPropertyFromOriginalRelease} from './withPropertyFromOriginalRelease.js';
diff --git a/src/data/composite/things/track/inheritFromOriginalRelease.js b/src/data/composite/things/track/inheritFromOriginalRelease.js
index 27ed1387..38ab06be 100644
--- a/src/data/composite/things/track/inheritFromOriginalRelease.js
+++ b/src/data/composite/things/track/inheritFromOriginalRelease.js
@@ -1,8 +1,6 @@
-// Early exits with a value inherited from the original release, if
-// this track is a rerelease, and otherwise continues with no further
-// dependencies provided. If allowOverride is true, then the continuation
-// will also be called if the original release exposed the requested
-// property as null.
+// Early exits with the value for the same property as specified on the
+// original release, if this track is a rerelease, and otherwise continues
+// without providing any further dependencies.
 //
 // Like withOriginalRelease, this will early exit (with notFoundValue) if the
 // original release is specified by reference and that reference doesn't
@@ -10,41 +8,34 @@
 
 import {input, templateCompositeFrom} from '#composite';
 
-import withOriginalRelease from './withOriginalRelease.js';
+import {exposeDependency, raiseOutputWithoutDependency}
+  from '#composite/control-flow';
+
+import withPropertyFromOriginalRelease
+  from './withPropertyFromOriginalRelease.js';
 
 export default templateCompositeFrom({
   annotation: `inheritFromOriginalRelease`,
 
   inputs: {
-    property: input({type: 'string'}),
-    allowOverride: input({type: 'boolean', defaultValue: false}),
-    notFoundValue: input({defaultValue: null}),
+    notFoundValue: input({
+      defaultValue: null,
+    }),
   },
 
   steps: () => [
-    withOriginalRelease({
+    withPropertyFromOriginalRelease({
+      property: input.thisProperty(),
       notFoundValue: input('notFoundValue'),
     }),
 
-    {
-      dependencies: [
-        '#originalRelease',
-        input('property'),
-        input('allowOverride'),
-      ],
-
-      compute: (continuation, {
-        ['#originalRelease']: originalRelease,
-        [input('property')]: originalProperty,
-        [input('allowOverride')]: allowOverride,
-      }) => {
-        if (!originalRelease) return continuation();
-
-        const value = originalRelease[originalProperty];
-        if (allowOverride && value === null) return continuation();
-
-        return continuation.exit(value);
-      },
-    },
+    raiseOutputWithoutDependency({
+      dependency: '#isRerelease',
+      mode: input.value('falsy'),
+    }),
+
+    exposeDependency({
+      dependency: '#originalValue',
+    }),
   ],
 });
diff --git a/src/data/composite/things/track/withPropertyFromOriginalRelease.js b/src/data/composite/things/track/withPropertyFromOriginalRelease.js
new file mode 100644
index 00000000..fd37f6de
--- /dev/null
+++ b/src/data/composite/things/track/withPropertyFromOriginalRelease.js
@@ -0,0 +1,86 @@
+// Provides a value inherited from the original release, if applicable, and a
+// flag indicating if this track is a rerelase or not.
+//
+// Like withOriginalRelease, this will early exit (with notFoundValue) if the
+// original release is specified by reference and that reference doesn't
+// resolve to anything.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {withResultOfAvailabilityCheck} from '#composite/control-flow';
+import {withPropertyFromObject} from '#composite/data';
+
+import withOriginalRelease from './withOriginalRelease.js';
+
+export default templateCompositeFrom({
+  annotation: `inheritFromOriginalRelease`,
+
+  inputs: {
+    property: input({type: 'string'}),
+
+    notFoundValue: input({
+      defaultValue: null,
+    }),
+  },
+
+  outputs: ({
+    [input.staticValue('property')]: property,
+  }) =>
+    ['#isRerelease'].concat(
+      (property
+        ? ['#original.' + property]
+        : ['#originalValue'])),
+
+  steps: () => [
+    withOriginalRelease({
+      notFoundValue: input('notFoundValue'),
+    }),
+
+    withResultOfAvailabilityCheck({
+      from: '#originalRelease',
+    }),
+
+    {
+      dependencies: [
+        '#availability',
+        input.staticValue('property'),
+      ],
+
+      compute: (continuation, {
+        ['#availability']: availability,
+        [input.staticValue('property')]: property,
+      }) =>
+        (availability
+          ? continuation()
+          : continuation.raiseOutput(
+              Object.assign(
+                {'#isRerelease': false},
+                (property
+                  ? {['#original.' + property]: null}
+                  : {'#originalValue': null})))),
+    },
+
+    withPropertyFromObject({
+      object: '#originalRelease',
+      property: input('property'),
+    }),
+
+    {
+      dependencies: [
+        '#value',
+        input.staticValue('property'),
+      ],
+
+      compute: (continuation, {
+        ['#value']: value,
+        [input.staticValue('property')]: property,
+      }) =>
+        continuation.raiseOutput(
+          Object.assign(
+            {'#isRerelease': true},
+            (property
+              ? {['#original.' + property]: value}
+              : {'#originalValue': value}))),
+    },
+  ],
+});