Add cache for project .gradle dir

- For now, this is limited to configuration-cache directory

src/cache-project-dot-gradle.ts

@@ -0,0 +1,109 @@
+import path from 'path'
+import fs from 'fs'
+
+import * as core from '@actions/core'
+import * as cache from '@actions/cache'
+import * as github from '@actions/github'
+import {truncateArgs} from './cache-utils'
+
+const PATHS_TO_CACHE = [
+    'configuration-cache' // Only configuration-cache is stored at present
+]
+const CACHE_KEY = 'PROJECT_CACHE_KEY'
+const CACHE_RESULT = 'PROJECT_CACHE_RESULT'
+
+export async function restore(rootDir: string): Promise<void> {
+    if (!isProjectDotGradleCacheEnabled()) return
+
+    if (projectDotGradleDirExists(rootDir)) {
+        core.debug(
+            'Project .gradle directory already exists. Not restoring from cache.'
+        )
+        return
+    }
+
+    const runnerOs = process.env[`RUNNER_OS`] || ''
+    const cacheKeyPrefix = `${runnerOs}-project|`
+
+    const args = truncateArgs(core.getInput('arguments'))
+    const cacheKeyWithArgs = `${cacheKeyPrefix}${args}|`
+
+    const cacheKey = `${cacheKeyWithArgs}${github.context.sha}`
+
+    core.saveState(CACHE_KEY, cacheKey)
+
+    const cacheResult = await cache.restoreCache(
+        getCachePath(rootDir),
+        cacheKey,
+        [cacheKeyWithArgs, cacheKeyPrefix]
+    )
+
+    if (!cacheResult) {
+        core.info('Project .gradle cache not found. Will start with empty.')
+        return
+    }
+
+    core.info(`Project .gradle dir restored from cache key: ${cacheResult}`)
+    return
+}
+
+export async function save(rootDir: string): Promise<void> {
+    if (!isProjectDotGradleCacheEnabled()) return
+
+    if (!projectDotGradleDirExists(rootDir)) {
+        core.debug('No project .gradle dir to cache.')
+        return
+    }
+
+    const cacheKey = core.getState(CACHE_KEY)
+    const cacheResult = core.getState(CACHE_RESULT)
+
+    if (!cacheKey) {
+        core.info(
+            'Project .gradle dir existed prior to cache restore. Not saving.'
+        )
+        return
+    }
+
+    if (cacheResult && cacheKey === cacheResult) {
+        core.info(
+            `Cache hit occurred on the cache key ${cacheKey}, not saving cache.`
+        )
+        return
+    }
+
+    core.info(`Caching project .gradle dir with cache key: ${cacheKey}`)
+    try {
+        await cache.saveCache(getCachePath(rootDir), cacheKey)
+    } catch (error) {
+        if (error.name === cache.ValidationError.name) {
+            throw error
+        } else if (error.name === cache.ReserveCacheError.name) {
+            core.info(error.message)
+        } else {
+            core.info(`[warning] ${error.message}`)
+        }
+    }
+
+    return
+}
+
+function isProjectDotGradleCacheEnabled(): boolean {
+    return core.getBooleanInput('project-dot-gradle-cache-enabled')
+}
+
+function getCachePath(rootDir: string): string[] {
+    const dir = getProjectDotGradleDir(rootDir)
+    return PATHS_TO_CACHE.map(x => path.resolve(dir, x))
+}
+
+function getProjectDotGradleDir(rootDir: string): string {
+    core.debug(`Resolving .gradle dir in ${rootDir}`)
+    return path.resolve(rootDir, '.gradle')
+}
+
+function projectDotGradleDirExists(rootDir: string): boolean {
+    const dir = getProjectDotGradleDir(rootDir)
+    core.debug(`Checking for existence of project .gradle dir: ${dir}`)
+    return fs.existsSync(dir)
+}