Report sizes of cache entries

Using the patched version of @actions/cache, we now report the total
size of cache entries restored/saved, as well as details of each one.

src/caches.ts

@@ -2,7 +2,7 @@ import {GradleUserHomeCache} from './cache-gradle-user-home'
 import {ProjectDotGradleCache} from './cache-project-dot-gradle'
 import * as core from '@actions/core'
 import {isCacheDisabled, isCacheReadOnly} from './cache-utils'
-import {CacheListener} from './cache-base'
+import {CacheEntryListener, CacheListener} from './cache-base'
 
 const BUILD_ROOT_DIR = 'BUILD_ROOT_DIR'
 const CACHE_LISTENER = 'CACHE_LISTENER'
@@ -54,11 +54,41 @@ export async function save(): Promise<void> {
 }
 
 function logCachingReport(listener: CacheListener): void {
-    core.info('---------- CACHING REPORT -------------')
+    core.info(`---------- Caching Summary -------------
+Restored Entries Count: ${getCount(listener.cacheEntries, e => e.restoredSize)}
+                  Size: ${getSum(listener.cacheEntries, e => e.restoredSize)}
+Saved Entries    Count: ${getCount(listener.cacheEntries, e => e.savedSize)}
+                  Size: ${getSum(listener.cacheEntries, e => e.savedSize)}`)
+
+    core.startGroup('Cache Entry details')
     for (const entry of listener.cacheEntries) {
-        core.info(`${entry.entryName}
-    Requested Key: ${entry.requestedKey ?? ''}
-    Restored Key : ${entry.restoredKey ?? ''}
-    Saved Key    : ${entry.savedKey ?? ''}`)
+        core.info(`Entry: ${entry.entryName}
+    Requested Key : ${entry.requestedKey ?? ''}
+    Restored  Key : ${entry.restoredKey ?? ''}
+              Size: ${formatSize(entry.restoredSize)}
+    Saved     Key : ${entry.savedKey ?? ''}
+              Size: ${formatSize(entry.savedSize)}`)
     }
+    core.endGroup()
+}
+
+function getCount(
+    cacheEntries: CacheEntryListener[],
+    predicate: (value: CacheEntryListener) => number | undefined
+): number {
+    return cacheEntries.filter(e => predicate(e) !== undefined).length
+}
+
+function getSum(
+    cacheEntries: CacheEntryListener[],
+    predicate: (value: CacheEntryListener) => number | undefined
+): string {
+    return formatSize(cacheEntries.map(e => predicate(e) ?? 0).reduce((p, v) => p + v, 0))
+}
+
+function formatSize(bytes: number | undefined): string {
+    if (bytes === undefined || bytes === 0) {
+        return ''
+    }
+    return `${Math.round(bytes / (1024 * 1024))} MB (${bytes} B)`
 }