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| 1 | +/* |
| 2 | + * Copyright 2018 LINE Corporation |
| 3 | + * |
| 4 | + * LINE Corporation licenses this file to you under the Apache License, |
| 5 | + * version 2.0 (the "License"); you may not use this file except in compliance |
| 6 | + * with the License. You may obtain a copy of the License at: |
| 7 | + * |
| 8 | + * https://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| 12 | + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| 13 | + * License for the specific language governing permissions and limitations |
| 14 | + * under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +package com.linecorp.armeria.rxjava; |
| 18 | + |
| 19 | +import javax.annotation.Nullable; |
| 20 | +import javax.annotation.concurrent.GuardedBy; |
| 21 | + |
| 22 | +import com.linecorp.armeria.common.RequestContext; |
| 23 | + |
| 24 | +import io.reactivex.rxjava3.core.Completable; |
| 25 | +import io.reactivex.rxjava3.core.Flowable; |
| 26 | +import io.reactivex.rxjava3.core.Maybe; |
| 27 | +import io.reactivex.rxjava3.core.Observable; |
| 28 | +import io.reactivex.rxjava3.core.Single; |
| 29 | +import io.reactivex.rxjava3.flowables.ConnectableFlowable; |
| 30 | +import io.reactivex.rxjava3.functions.Function; |
| 31 | +import io.reactivex.rxjava3.functions.Supplier; |
| 32 | +import io.reactivex.rxjava3.internal.fuseable.ScalarSupplier; |
| 33 | +import io.reactivex.rxjava3.observables.ConnectableObservable; |
| 34 | +import io.reactivex.rxjava3.parallel.ParallelFlowable; |
| 35 | +import io.reactivex.rxjava3.plugins.RxJavaPlugins; |
| 36 | + |
| 37 | +/** |
| 38 | + * Utility class to keep {@link RequestContext} during RxJava operations. |
| 39 | + */ |
| 40 | +public final class RequestContextAssembly { |
| 41 | + |
| 42 | + @SuppressWarnings("rawtypes") |
| 43 | + @Nullable |
| 44 | + @GuardedBy("RequestContextAssembly.class") |
| 45 | + private static Function<? super Observable, ? extends Observable> oldOnObservableAssembly; |
| 46 | + @SuppressWarnings("rawtypes") |
| 47 | + @Nullable |
| 48 | + @GuardedBy("RequestContextAssembly.class") |
| 49 | + private static Function<? super ConnectableObservable, ? extends ConnectableObservable> |
| 50 | + oldOnConnectableObservableAssembly; |
| 51 | + @SuppressWarnings("rawtypes") |
| 52 | + @Nullable |
| 53 | + @GuardedBy("RequestContextAssembly.class") |
| 54 | + private static Function<? super Completable, ? extends Completable> oldOnCompletableAssembly; |
| 55 | + @SuppressWarnings("rawtypes") |
| 56 | + @Nullable |
| 57 | + @GuardedBy("RequestContextAssembly.class") |
| 58 | + private static Function<? super Single, ? extends Single> oldOnSingleAssembly; |
| 59 | + @SuppressWarnings("rawtypes") |
| 60 | + @Nullable |
| 61 | + @GuardedBy("RequestContextAssembly.class") |
| 62 | + private static Function<? super Maybe, ? extends Maybe> oldOnMaybeAssembly; |
| 63 | + @SuppressWarnings("rawtypes") |
| 64 | + @Nullable |
| 65 | + @GuardedBy("RequestContextAssembly.class") |
| 66 | + private static Function<? super Flowable, ? extends Flowable> oldOnFlowableAssembly; |
| 67 | + @SuppressWarnings("rawtypes") |
| 68 | + @Nullable |
| 69 | + @GuardedBy("RequestContextAssembly.class") |
| 70 | + private static Function<? super ConnectableFlowable, ? extends ConnectableFlowable> |
| 71 | + oldOnConnectableFlowableAssembly; |
| 72 | + @SuppressWarnings("rawtypes") |
| 73 | + @Nullable |
| 74 | + @GuardedBy("RequestContextAssembly.class") |
| 75 | + private static Function<? super ParallelFlowable, ? extends ParallelFlowable> oldOnParallelAssembly; |
| 76 | + |
| 77 | + @GuardedBy("RequestContextAssembly.class") |
| 78 | + private static boolean enabled; |
| 79 | + |
| 80 | + private RequestContextAssembly() { |
| 81 | + } |
| 82 | + |
| 83 | + /** |
| 84 | + * Enable {@link RequestContext} during operators. |
| 85 | + */ |
| 86 | + @SuppressWarnings({ "rawtypes", "unchecked" }) |
| 87 | + public static synchronized void enable() { |
| 88 | + if (enabled) { |
| 89 | + return; |
| 90 | + } |
| 91 | + |
| 92 | + oldOnObservableAssembly = RxJavaPlugins.getOnObservableAssembly(); |
| 93 | + RxJavaPlugins.setOnObservableAssembly(compose( |
| 94 | + oldOnObservableAssembly, |
| 95 | + new ConditionalOnCurrentRequestContextFunction<Observable>() { |
| 96 | + @Override |
| 97 | + Observable applyActual(Observable o, RequestContext ctx) { |
| 98 | + if (!(o instanceof Supplier)) { |
| 99 | + return new RequestContextObservable(o, ctx); |
| 100 | + } |
| 101 | + if (o instanceof ScalarSupplier) { |
| 102 | + return new RequestContextScalarSupplierObservable(o, ctx); |
| 103 | + } |
| 104 | + return new RequestContextSupplierObservable(o, ctx); |
| 105 | + } |
| 106 | + })); |
| 107 | + |
| 108 | + oldOnConnectableObservableAssembly = RxJavaPlugins.getOnConnectableObservableAssembly(); |
| 109 | + RxJavaPlugins.setOnConnectableObservableAssembly(compose( |
| 110 | + oldOnConnectableObservableAssembly, |
| 111 | + new ConditionalOnCurrentRequestContextFunction<ConnectableObservable>() { |
| 112 | + @Override |
| 113 | + ConnectableObservable applyActual(ConnectableObservable co, RequestContext ctx) { |
| 114 | + return new RequestContextConnectableObservable(co, ctx); |
| 115 | + } |
| 116 | + })); |
| 117 | + |
| 118 | + oldOnCompletableAssembly = RxJavaPlugins.getOnCompletableAssembly(); |
| 119 | + RxJavaPlugins.setOnCompletableAssembly( |
| 120 | + compose(oldOnCompletableAssembly, |
| 121 | + new ConditionalOnCurrentRequestContextFunction<Completable>() { |
| 122 | + @Override |
| 123 | + Completable applyActual(Completable c, RequestContext ctx) { |
| 124 | + return new RequestContextCompletable(c, ctx); |
| 125 | + } |
| 126 | + })); |
| 127 | + |
| 128 | + oldOnSingleAssembly = RxJavaPlugins.getOnSingleAssembly(); |
| 129 | + RxJavaPlugins.setOnSingleAssembly( |
| 130 | + compose(oldOnSingleAssembly, new ConditionalOnCurrentRequestContextFunction<Single>() { |
| 131 | + @Override |
| 132 | + Single applyActual(Single s, RequestContext ctx) { |
| 133 | + if (!(s instanceof Supplier)) { |
| 134 | + return new RequestContextSingle(s, ctx); |
| 135 | + } |
| 136 | + if (s instanceof ScalarSupplier) { |
| 137 | + return new RequestContextScalarSupplierSingle(s, ctx); |
| 138 | + } |
| 139 | + return new RequestContextSupplierSingle(s, ctx); |
| 140 | + } |
| 141 | + })); |
| 142 | + |
| 143 | + oldOnMaybeAssembly = RxJavaPlugins.getOnMaybeAssembly(); |
| 144 | + RxJavaPlugins.setOnMaybeAssembly( |
| 145 | + compose(oldOnMaybeAssembly, new ConditionalOnCurrentRequestContextFunction<Maybe>() { |
| 146 | + @Override |
| 147 | + Maybe applyActual(Maybe m, RequestContext ctx) { |
| 148 | + if (!(m instanceof Supplier)) { |
| 149 | + return new RequestContextMaybe(m, ctx); |
| 150 | + } |
| 151 | + if (m instanceof ScalarSupplier) { |
| 152 | + return new RequestContextScalarSupplierMaybe(m, ctx); |
| 153 | + } |
| 154 | + return new RequestContextSupplierMaybe(m, ctx); |
| 155 | + } |
| 156 | + })); |
| 157 | + |
| 158 | + oldOnFlowableAssembly = RxJavaPlugins.getOnFlowableAssembly(); |
| 159 | + RxJavaPlugins.setOnFlowableAssembly( |
| 160 | + compose(oldOnFlowableAssembly, new ConditionalOnCurrentRequestContextFunction<Flowable>() { |
| 161 | + @Override |
| 162 | + Flowable applyActual(Flowable f, RequestContext ctx) { |
| 163 | + if (!(f instanceof Supplier)) { |
| 164 | + return new RequestContextFlowable(f, ctx); |
| 165 | + } |
| 166 | + if (f instanceof ScalarSupplier) { |
| 167 | + return new RequestContextScalarSupplierFlowable(f, ctx); |
| 168 | + } |
| 169 | + return new RequestContextSupplierFlowable(f, ctx); |
| 170 | + } |
| 171 | + })); |
| 172 | + |
| 173 | + oldOnConnectableFlowableAssembly = RxJavaPlugins.getOnConnectableFlowableAssembly(); |
| 174 | + RxJavaPlugins.setOnConnectableFlowableAssembly( |
| 175 | + compose(oldOnConnectableFlowableAssembly, |
| 176 | + new ConditionalOnCurrentRequestContextFunction<ConnectableFlowable>() { |
| 177 | + @Override |
| 178 | + ConnectableFlowable applyActual( |
| 179 | + ConnectableFlowable cf, |
| 180 | + RequestContext ctx) { |
| 181 | + return new RequestContextConnectableFlowable( |
| 182 | + cf, ctx); |
| 183 | + } |
| 184 | + } |
| 185 | + )); |
| 186 | + |
| 187 | + oldOnParallelAssembly = RxJavaPlugins.getOnParallelAssembly(); |
| 188 | + RxJavaPlugins.setOnParallelAssembly( |
| 189 | + compose(oldOnParallelAssembly, |
| 190 | + new ConditionalOnCurrentRequestContextFunction<ParallelFlowable>() { |
| 191 | + @Override |
| 192 | + ParallelFlowable applyActual(ParallelFlowable pf, RequestContext ctx) { |
| 193 | + return new RequestContextParallelFlowable(pf, ctx); |
| 194 | + } |
| 195 | + } |
| 196 | + )); |
| 197 | + enabled = true; |
| 198 | + } |
| 199 | + |
| 200 | + /** |
| 201 | + * Disable {@link RequestContext} during operators. |
| 202 | + */ |
| 203 | + public static synchronized void disable() { |
| 204 | + if (!enabled) { |
| 205 | + return; |
| 206 | + } |
| 207 | + RxJavaPlugins.setOnObservableAssembly(oldOnObservableAssembly); |
| 208 | + oldOnObservableAssembly = null; |
| 209 | + RxJavaPlugins.setOnConnectableObservableAssembly(oldOnConnectableObservableAssembly); |
| 210 | + oldOnConnectableObservableAssembly = null; |
| 211 | + RxJavaPlugins.setOnCompletableAssembly(oldOnCompletableAssembly); |
| 212 | + oldOnCompletableAssembly = null; |
| 213 | + RxJavaPlugins.setOnSingleAssembly(oldOnSingleAssembly); |
| 214 | + oldOnSingleAssembly = null; |
| 215 | + RxJavaPlugins.setOnMaybeAssembly(oldOnMaybeAssembly); |
| 216 | + oldOnMaybeAssembly = null; |
| 217 | + RxJavaPlugins.setOnFlowableAssembly(oldOnFlowableAssembly); |
| 218 | + oldOnFlowableAssembly = null; |
| 219 | + RxJavaPlugins.setOnConnectableFlowableAssembly(oldOnConnectableFlowableAssembly); |
| 220 | + oldOnConnectableFlowableAssembly = null; |
| 221 | + RxJavaPlugins.setOnParallelAssembly(oldOnParallelAssembly); |
| 222 | + oldOnParallelAssembly = null; |
| 223 | + enabled = false; |
| 224 | + } |
| 225 | + |
| 226 | + private abstract static class ConditionalOnCurrentRequestContextFunction<T> implements Function<T, T> { |
| 227 | + @Override |
| 228 | + public final T apply(T t) { |
| 229 | + return RequestContext.mapCurrent(requestContext -> applyActual(t, requestContext), () -> t); |
| 230 | + } |
| 231 | + |
| 232 | + abstract T applyActual(T t, RequestContext ctx); |
| 233 | + } |
| 234 | + |
| 235 | + private static <T> Function<? super T, ? extends T> compose( |
| 236 | + @Nullable Function<? super T, ? extends T> before, |
| 237 | + Function<? super T, ? extends T> after) { |
| 238 | + if (before == null) { |
| 239 | + return after; |
| 240 | + } |
| 241 | + return (T v) -> after.apply(before.apply(v)); |
| 242 | + } |
| 243 | +} |
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