feat: 汎用ResourceResolverを追加

src/main/kotlin/dev/usbharu/hideout/core/service/resource/CacheManager.kt

@@ -0,0 +1,6 @@
+package dev.usbharu.hideout.core.service.resource
+
+interface CacheManager {
+    suspend fun putCache(key: String, block: suspend () -> ResolveResponse)
+    suspend fun getOrWait(key: String): ResolveResponse
+}

src/main/kotlin/dev/usbharu/hideout/core/service/resource/InMemoryCacheManager.kt

@@ -0,0 +1,49 @@
+package dev.usbharu.hideout.core.service.resource
+
+import dev.usbharu.hideout.util.LruCache
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import org.springframework.stereotype.Service
+import java.time.Instant
+
+@Service
+class InMemoryCacheManager : CacheManager {
+    private val cacheKey = LruCache<String, Long>(15)
+    private val valueStore = mutableMapOf<String, ResolveResponse>()
+    private val keyMutex = Mutex()
+
+    override suspend fun putCache(key: String, block: suspend () -> ResolveResponse) {
+        val needRunBlock: Boolean
+        keyMutex.withLock {
+            cacheKey.filter { Instant.ofEpochMilli(it.value).plusSeconds(300) <= Instant.now() }
+
+            val cached = cacheKey.get(key)
+            if (cached == null) {
+                needRunBlock = true
+                cacheKey[key] = Instant.now().toEpochMilli()
+
+                valueStore.remove(key)
+            } else {
+                needRunBlock = false
+            }
+        }
+        if (needRunBlock) {
+            val processed = block()
+
+            if (cacheKey.containsKey(key)) {
+                valueStore[key] = processed
+            }
+        }
+    }
+
+    override suspend fun getOrWait(key: String): ResolveResponse {
+        while (valueStore.contains(key).not()) {
+            if (cacheKey.containsKey(key).not()) {
+                throw IllegalStateException("Invalid cache key.")
+            }
+            delay(1)
+        }
+        return valueStore.getValue(key)
+    }
+}

src/main/kotlin/dev/usbharu/hideout/core/service/resource/KtorResolveResponse.kt

@@ -0,0 +1,14 @@
+package dev.usbharu.hideout.core.service.resource
+
+import io.ktor.client.statement.*
+import io.ktor.util.*
+import io.ktor.utils.io.jvm.javaio.*
+import java.io.InputStream
+
+class KtorResolveResponse(val ktorHttpResponse: HttpResponse) : ResolveResponse {
+
+    override suspend fun body(): InputStream = ktorHttpResponse.bodyAsChannel().toInputStream()
+    override suspend fun header(): Map<String, List<String>> = ktorHttpResponse.headers.toMap()
+    override suspend fun status(): Int = ktorHttpResponse.status.value
+    override suspend fun statusMessage(): String = ktorHttpResponse.status.description
+}

src/main/kotlin/dev/usbharu/hideout/core/service/resource/KtorResourceResolveService.kt

@@ -0,0 +1,24 @@
+package dev.usbharu.hideout.core.service.resource
+
+import io.ktor.client.*
+import io.ktor.client.request.*
+import org.springframework.stereotype.Service
+
+@Service
+open class KtorResourceResolveService(private val httpClient: HttpClient, private val cacheManager: CacheManager) :
+    ResourceResolveService {
+    override suspend fun resolve(url: String): ResolveResponse {
+        cacheManager.putCache(getCacheKey(url)) {
+            runResolve(url)
+        }
+        return cacheManager.getOrWait(getCacheKey(url))
+    }
+
+    protected suspend fun runResolve(url: String): ResolveResponse {
+        val httpResponse = httpClient.get(url)
+
+        return KtorResolveResponse(httpResponse)
+    }
+
+    protected suspend fun getCacheKey(url: String) = url
+}

src/main/kotlin/dev/usbharu/hideout/core/service/resource/ResolveResponse.kt

@@ -0,0 +1,10 @@
+package dev.usbharu.hideout.core.service.resource
+
+import java.io.InputStream
+
+interface ResolveResponse {
+    suspend fun body(): InputStream
+    suspend fun header(): Map<String, List<String>>
+    suspend fun status(): Int
+    suspend fun statusMessage(): String
+}

src/main/kotlin/dev/usbharu/hideout/core/service/resource/ResourceResolveService.kt

@@ -0,0 +1,5 @@
+package dev.usbharu.hideout.core.service.resource
+
+interface ResourceResolveService {
+    suspend fun resolve(url: String): ResolveResponse
+}