aboutsummaryrefslogtreecommitdiff
path: root/core/src/main/kotlin/plugability/DokkaContext.kt
blob: 61ae1918c56f9ddc11aab1717235b881ee31fb6b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
package org.jetbrains.dokka.plugability

import org.jetbrains.dokka.DokkaConfiguration
import org.jetbrains.dokka.utilities.DokkaLogger
import java.io.File
import java.net.URLClassLoader
import java.util.*
import kotlin.reflect.KClass
import kotlin.reflect.full.createInstance


interface DokkaContext {
    fun <T : DokkaPlugin> plugin(kclass: KClass<T>): T?

    operator fun <T, E> get(point: E): List<T>
            where T : Any, E : ExtensionPoint<T>

    fun <T, E> single(point: E): T where T : Any, E : ExtensionPoint<T>

    val logger: DokkaLogger
    val configuration: DokkaConfiguration
    val unusedPoints: Collection<ExtensionPoint<*>>


    companion object {
        fun create(
            configuration: DokkaConfiguration,
            logger: DokkaLogger,
            pluginOverrides: List<DokkaPlugin>
        ): DokkaContext =
            DokkaContextConfigurationImpl(logger, configuration).apply {
                // File(it.path) is a workaround for an incorrect filesystem in a File instance returned by Gradle.
                configuration.pluginsClasspath.map { File(it.path).toURI().toURL() }
                    .toTypedArray()
                    .let { URLClassLoader(it, this.javaClass.classLoader) }
                    .also { checkClasspath(it) }
                    .let { ServiceLoader.load(DokkaPlugin::class.java, it) }
                    .let { it + pluginOverrides }
                    .forEach { install(it) }
                topologicallySortAndPrune()
            }.also { it.logInitialisationInfo() }
    }
}

inline fun <reified T : DokkaPlugin> DokkaContext.plugin(): T = plugin(T::class)
    ?: throw java.lang.IllegalStateException("Plugin ${T::class.qualifiedName} is not present in context.")

interface DokkaContextConfiguration {
    fun installExtension(extension: Extension<*, *, *>)
}

private class DokkaContextConfigurationImpl(
    override val logger: DokkaLogger,
    override val configuration: DokkaConfiguration
) : DokkaContext, DokkaContextConfiguration {
    private val plugins = mutableMapOf<KClass<*>, DokkaPlugin>()
    private val pluginStubs = mutableMapOf<KClass<*>, DokkaPlugin>()
    val extensions = mutableMapOf<ExtensionPoint<*>, MutableList<Extension<*, *, *>>>()
    val pointsUsed: MutableSet<ExtensionPoint<*>> = mutableSetOf()
    val pointsPopulated: MutableSet<ExtensionPoint<*>> = mutableSetOf()
    override val unusedPoints: Set<ExtensionPoint<*>>
        get() = pointsPopulated - pointsUsed

    private enum class State {
        UNVISITED,
        VISITING,
        VISITED;
    }

    private sealed class Suppression {
        data class ByExtension(val extension: Extension<*, *, *>) : Suppression() {
            override fun toString() = extension.toString()
        }

        data class ByPlugin(val plugin: DokkaPlugin) : Suppression() {
            override fun toString() = "Plugin ${plugin::class.qualifiedName}"
        }
    }

    private val rawExtensions = mutableListOf<Extension<*, *, *>>()
    private val rawAdjacencyList = mutableMapOf<Extension<*, *, *>, MutableList<Extension<*, *, *>>>()
    private val suppressedExtensions = mutableMapOf<Extension<*, *, *>, MutableList<Suppression>>()

    fun topologicallySortAndPrune() {
        pointsPopulated.clear()
        extensions.clear()

        val overridesInfo = processOverrides()
        val extensionsToSort = overridesInfo.keys
        val adjacencyList = translateAdjacencyList(overridesInfo)

        val verticesWithState = extensionsToSort.associateWithTo(mutableMapOf()) { State.UNVISITED }
        val result: MutableList<Extension<*, *, *>> = mutableListOf()

        fun visit(n: Extension<*, *, *>) {
            val state = verticesWithState[n]
            if (state == State.VISITED)
                return
            if (state == State.VISITING)
                throw Error("Detected cycle in plugins graph")
            verticesWithState[n] = State.VISITING
            adjacencyList[n]?.forEach { visit(it) }
            verticesWithState[n] = State.VISITED
            result += n
        }

        extensionsToSort.forEach(::visit)

        val filteredResult = result.asReversed().filterNot { it in suppressedExtensions }

        filteredResult.mapTo(pointsPopulated) { it.extensionPoint }
        filteredResult.groupByTo(extensions) { it.extensionPoint }
    }

    private fun processOverrides(): Map<Extension<*, *, *>, Set<Extension<*, *, *>>> {
        val buckets = rawExtensions.associateWithTo(mutableMapOf()) { setOf(it) }
        suppressedExtensions.forEach { (extension, suppressions) ->
            val mergedBucket = suppressions.filterIsInstance<Suppression.ByExtension>()
                .map { it.extension }
                .plus(extension)
                .flatMap { buckets[it].orEmpty() }
                .toSet()
            mergedBucket.forEach { buckets[it] = mergedBucket }
        }
        return buckets.values.distinct().associateBy(::findNotOverridden)
    }

    private fun findNotOverridden(bucket: Set<Extension<*, *, *>>): Extension<*, *, *> {
        val filtered = bucket.filter { it !in suppressedExtensions }
        return filtered.singleOrNull() ?: throw IllegalStateException("Conflicting overrides: $filtered")
    }

    private fun translateAdjacencyList(
        overridesInfo: Map<Extension<*, *, *>, Set<Extension<*, *, *>>>
    ): Map<Extension<*, *, *>, List<Extension<*, *, *>>> {
        val reverseOverrideInfo = overridesInfo.flatMap { (ext, set) -> set.map { it to ext } }.toMap()
        return rawAdjacencyList.mapNotNull { (ext, list) ->
            reverseOverrideInfo[ext]?.to(list.mapNotNull { reverseOverrideInfo[it] })
        }.toMap()
    }

    @Suppress("UNCHECKED_CAST")
    override operator fun <T, E> get(point: E) where T : Any, E : ExtensionPoint<T> =
        actions(point).also { pointsUsed += point }.orEmpty() as List<T>

    @Suppress("UNCHECKED_CAST")
    override fun <T, E> single(point: E): T where T : Any, E : ExtensionPoint<T> {
        fun throwBadArity(substitution: String): Nothing = throw IllegalStateException(
            "$point was expected to have exactly one extension registered, but $substitution found."
        )
        pointsUsed += point

        val extensions = extensions[point].orEmpty() as List<Extension<T, *, *>>
        return when (extensions.size) {
            0 -> throwBadArity("none was")
            1 -> extensions.single().action.get(this)
            else -> throwBadArity("many were")
        }
    }

    private fun <E : ExtensionPoint<*>> actions(point: E) = extensions[point]?.map { it.action.get(this) }

    @Suppress("UNCHECKED_CAST")
    override fun <T : DokkaPlugin> plugin(kclass: KClass<T>) = (plugins[kclass] ?: pluginStubFor(kclass)) as T

    private fun <T : DokkaPlugin> pluginStubFor(kclass: KClass<T>): DokkaPlugin =
        pluginStubs.getOrPut(kclass) { kclass.createInstance().also { it.context = this } }

    fun install(plugin: DokkaPlugin) {
        plugins[plugin::class] = plugin
        plugin.context = this
        plugin.internalInstall(this, this.configuration)

        if (plugin is WithUnsafeExtensionSuppression) {
            plugin.extensionsSuppressed.forEach {
                suppressedExtensions.listFor(it) += Suppression.ByPlugin(plugin)
            }
        }
    }

    override fun installExtension(extension: Extension<*, *, *>) {
        rawExtensions += extension

        if (extension.ordering is OrderingKind.ByDsl) {
            val orderDsl = OrderDsl()
            orderDsl.(extension.ordering.block)()

            rawAdjacencyList.listFor(extension) += orderDsl.following.toList()
            orderDsl.previous.forEach { rawAdjacencyList.listFor(it) += extension }
        }

        if (extension.override is OverrideKind.Present) {
            suppressedExtensions.listFor(extension.override.overriden) += Suppression.ByExtension(extension)
        }
    }

    fun logInitialisationInfo() {
        val pluginNames = plugins.values.map { it::class.qualifiedName.toString() }

        val loadedListForDebug = extensions.run { keys + values.flatten() }.toList()
            .joinToString(prefix = "[\n", separator = ",\n", postfix = "\n]") { "\t$it" }

        val suppressedList = suppressedExtensions.asSequence()
            .joinToString(prefix = "[\n", separator = ",\n", postfix = "\n]") {
                "\t${it.key} by " + (it.value.singleOrNull() ?: it.value)
            }

        logger.progress("Loaded plugins: $pluginNames")
        logger.progress("Loaded: $loadedListForDebug")
        logger.progress("Suppressed: $suppressedList")
    }
}

private fun checkClasspath(classLoader: URLClassLoader) {
    classLoader.findResource(DokkaContext::class.java.name.replace('.', '/') + ".class")?.also {
        throw AssertionError(
            "Dokka API found on plugins classpath. This will lead to subtle bugs. " +
                    "Please fix your plugins dependencies or exclude dokka api artifact from plugin classpath"
        )
    }
}

private fun <K, V> MutableMap<K, MutableList<V>>.listFor(key: K) = getOrPut(key, ::mutableListOf)