From 5ff0c5889fcf39725dabe38d4a7fcb1723d0cb82 Mon Sep 17 00:00:00 2001
From: Kirill Nayduik <kirill.nayduikkn1@gmail.com>
Date: Tue, 12 Apr 2022 15:56:24 +0300
Subject: [PATCH] Add implementation of blocking requests

---
 .../touchin/network/blocking/BlockingCall.kt  | 54 +++++++++++++++++++
 .../network/blocking/BlockingRequest.kt       |  5 ++
 .../blocking/BlockingRequestCallAdapter.kt    | 27 ++++++++++
 .../blocking/PendingRequestsManager.kt        | 35 ++++++++++++
 .../java/ru/touchin/network/utils/Request.kt  |  6 +++
 5 files changed, 127 insertions(+)
 create mode 100644 network/src/main/java/ru/touchin/network/blocking/BlockingCall.kt
 create mode 100644 network/src/main/java/ru/touchin/network/blocking/BlockingRequest.kt
 create mode 100644 network/src/main/java/ru/touchin/network/blocking/BlockingRequestCallAdapter.kt
 create mode 100644 network/src/main/java/ru/touchin/network/blocking/PendingRequestsManager.kt
 create mode 100644 network/src/main/java/ru/touchin/network/utils/Request.kt

diff --git a/network/src/main/java/ru/touchin/network/blocking/BlockingCall.kt b/network/src/main/java/ru/touchin/network/blocking/BlockingCall.kt
new file mode 100644
index 0000000..7d2812a
--- /dev/null
+++ b/network/src/main/java/ru/touchin/network/blocking/BlockingCall.kt
@@ -0,0 +1,54 @@
+package ru.touchin.network.blocking
+
+import okhttp3.Request
+import okio.Timeout
+import retrofit2.Call
+import retrofit2.Callback
+import retrofit2.Response
+import ru.touchin.network.utils.getAnnotation
+
+class BlockingCall(
+        private val callDelegate: Call<Any>
+) : Call<Any> {
+    override fun clone(): Call<Any> = callDelegate.clone()
+
+    override fun execute(): Response<Any> {
+        return callDelegate.execute()
+    }
+
+    override fun enqueue(callback: Callback<Any>) {
+        if (PendingRequestsManager.isPending.get()) {
+            PendingRequestsManager.addPendingRequest(callDelegate, callback)
+            return
+        }
+
+        val isBlocking = callDelegate.isBlocking()
+        if (isBlocking) PendingRequestsManager.isPending.set(true)
+
+        callDelegate.enqueue(object: Callback<Any> {
+            override fun onResponse(call: Call<Any>, response: Response<Any>) {
+                callback.onResponse(call, response)
+
+                if (isBlocking) PendingRequestsManager.executePendingRequests()
+            }
+
+            override fun onFailure(call: Call<Any>, t: Throwable) {
+                callback.onFailure(call, t)
+
+                if (isBlocking) PendingRequestsManager.dropPendingRequests()
+            }
+        })
+    }
+
+    override fun isExecuted(): Boolean = callDelegate.isExecuted
+
+    override fun cancel() = callDelegate.cancel()
+
+    override fun isCanceled(): Boolean = callDelegate.isCanceled
+
+    override fun request(): Request = callDelegate.request()
+
+    override fun timeout(): Timeout = callDelegate.timeout()
+
+    private fun Call<Any>.isBlocking() = request().getAnnotation(BlockingRequest::class.java) != null
+}
diff --git a/network/src/main/java/ru/touchin/network/blocking/BlockingRequest.kt b/network/src/main/java/ru/touchin/network/blocking/BlockingRequest.kt
new file mode 100644
index 0000000..1cf3995
--- /dev/null
+++ b/network/src/main/java/ru/touchin/network/blocking/BlockingRequest.kt
@@ -0,0 +1,5 @@
+package ru.touchin.network.blocking
+
+@Retention(AnnotationRetention.RUNTIME)
+@Target(AnnotationTarget.FUNCTION)
+annotation class BlockingRequest(val abortOnFail: Boolean = false)
diff --git a/network/src/main/java/ru/touchin/network/blocking/BlockingRequestCallAdapter.kt b/network/src/main/java/ru/touchin/network/blocking/BlockingRequestCallAdapter.kt
new file mode 100644
index 0000000..310fb56
--- /dev/null
+++ b/network/src/main/java/ru/touchin/network/blocking/BlockingRequestCallAdapter.kt
@@ -0,0 +1,27 @@
+package ru.touchin.network.blocking
+
+import retrofit2.Call
+import retrofit2.CallAdapter
+import retrofit2.Retrofit
+import java.lang.reflect.ParameterizedType
+import java.lang.reflect.Type
+
+class BlockingRequestCallAdapter private constructor(
+        private val responseType: Type
+) : CallAdapter<Any, Any> {
+
+    companion object {
+        fun create() = object : CallAdapter.Factory() {
+            override fun get(returnType: Type, annotations: Array<out Annotation>, retrofit: Retrofit): CallAdapter<*, *>? {
+                return (returnType as? ParameterizedType)
+                        ?.let { BlockingRequestCallAdapter(responseType = it.actualTypeArguments[0]) }
+            }
+        }
+    }
+
+    override fun responseType(): Type = responseType
+
+    override fun adapt(call: Call<Any>): Any {
+        return BlockingCall(call)
+    }
+}
diff --git a/network/src/main/java/ru/touchin/network/blocking/PendingRequestsManager.kt b/network/src/main/java/ru/touchin/network/blocking/PendingRequestsManager.kt
new file mode 100644
index 0000000..a82c238
--- /dev/null
+++ b/network/src/main/java/ru/touchin/network/blocking/PendingRequestsManager.kt
@@ -0,0 +1,35 @@
+package ru.touchin.network.blocking
+
+import retrofit2.Call
+import retrofit2.Callback
+import java.util.concurrent.atomic.AtomicBoolean
+
+object PendingRequestsManager {
+
+    val isPending = AtomicBoolean(false)
+
+    private val pendingRequests = mutableListOf<Pair<Call<Any>, Callback<Any>>>()
+
+    fun addPendingRequest(call: Call<Any>, callback: Callback<Any>) {
+        pendingRequests.add(call to callback)
+    }
+
+    @Synchronized
+    fun executePendingRequests() {
+        applyActionToPendingRequests { first.enqueue(second) }
+    }
+
+    @Synchronized
+    fun dropPendingRequests() {
+        applyActionToPendingRequests { first.cancel() }
+    }
+
+    private fun applyActionToPendingRequests(action: Pair<Call<Any>, Callback<Any>>.() -> Unit) {
+        isPending.set(false)
+
+        pendingRequests.forEach { it.action() }
+
+        pendingRequests.clear()
+    }
+
+}
diff --git a/network/src/main/java/ru/touchin/network/utils/Request.kt b/network/src/main/java/ru/touchin/network/utils/Request.kt
new file mode 100644
index 0000000..842081c
--- /dev/null
+++ b/network/src/main/java/ru/touchin/network/utils/Request.kt
@@ -0,0 +1,6 @@
+package ru.touchin.network.utils
+
+import okhttp3.Request
+import retrofit2.Invocation
+
+fun <T: Annotation> Request.getAnnotation(annotation: Class<T>) = tag(Invocation::class.java)?.method()?.getAnnotation(annotation)