1 files changed, 142 insertions, 0 deletions
diff --git a/plugins/base/src/main/kotlin/resolvers/local/BaseLocationProvider.kt b/plugins/base/src/main/kotlin/resolvers/local/BaseLocationProvider.kt
new file mode 100644
index 00000000..4204006e
--- /dev/null
+++ b/plugins/base/src/main/kotlin/resolvers/local/BaseLocationProvider.kt
@@ -0,0 +1,142 @@
+package org.jetbrains.dokka.base.resolvers.local
+
+import org.jetbrains.dokka.DokkaConfiguration
+import org.jetbrains.dokka.DokkaConfiguration.DokkaSourceSet
+import org.jetbrains.dokka.base.DokkaBase
+import org.jetbrains.dokka.links.DRI
+import org.jetbrains.dokka.plugability.DokkaContext
+import org.jetbrains.dokka.plugability.plugin
+import org.jetbrains.dokka.plugability.query
+import java.net.HttpURLConnection
+import java.net.URL
+import java.net.URLConnection
+import java.util.concurrent.locks.ReentrantReadWriteLock
+import kotlin.concurrent.read
+import kotlin.concurrent.write
+
+abstract class BaseLocationProvider(protected val dokkaContext: DokkaContext) : LocationProvider {
+
+    protected val externalLocationProviderFactories =
+        dokkaContext.plugin<DokkaBase>().query { externalLocationProviderFactory }
+    private val cache: MutableMap<URL, DefaultLocationProvider.LocationInfo> = mutableMapOf()
+    private val lock = ReentrantReadWriteLock()
+
+    protected fun getExternalLocation(
+        dri: DRI,
+        sourceSets: Set<DokkaSourceSet>
+    ): String {
+        val jdkToExternalDocumentationLinks = dokkaContext.configuration.sourceSets
+            .filter { sourceSet ->
+                sourceSets.contains(sourceSet)
+            }
+            .groupBy({ it.jdkVersion }, { it.externalDocumentationLinks })
+            .map { it.key to it.value.flatten().distinct() }.toMap()
+
+        val toResolve: MutableMap<Int, MutableList<DokkaConfiguration.ExternalDocumentationLink>> = mutableMapOf()
+        for ((jdk, links) in jdkToExternalDocumentationLinks) {
+            for (link in links) {
+                val info = lock.read { cache[link.packageListUrl] }
+                if (info == null) {
+                    toResolve.getOrPut(jdk) { mutableListOf() }.add(link)
+                } else if (info.packages.contains(dri.packageName)) {
+                    return link.url.toExternalForm() + getLink(dri, info)
+                }
+            }
+        }
+        // Not in cache, resolve packageLists
+        for ((jdk, links) in toResolve) {
+            for (link in links) {
+                if (dokkaContext.configuration.offlineMode && link.packageListUrl.protocol.toLowerCase() != "file")
+                    continue
+                val locationInfo =
+                    loadPackageList(jdk, link.packageListUrl)
+                if (locationInfo.packages.contains(dri.packageName)) {
+                    return link.url.toExternalForm() + getLink(dri, locationInfo)
+                }
+            }
+            toResolve.remove(jdk)
+        }
+        return ""
+    }
+
+    private fun getLink(dri: DRI, locationInfo: DefaultLocationProvider.LocationInfo): String =
+        locationInfo.locations[dri.packageName + "." + dri.classNames]
+            ?: // Not sure if it can be here, previously it shadowed only kotlin/dokka related sources, here it shadows both dokka/javadoc, cause I cannot distinguish what LocationProvider has been hypothetically chosen
+            if (locationInfo.externalLocationProvider != null)
+                with(locationInfo.externalLocationProvider) {
+                    dri.toLocation()
+                }
+            else
+                throw IllegalStateException("Have not found any convenient ExternalLocationProvider for $dri DRI!")
+
+    private fun loadPackageList(jdk: Int, url: URL): DefaultLocationProvider.LocationInfo = lock.write {
+        val packageListStream = url.doOpenConnectionToReadContent().getInputStream()
+        val (params, packages) =
+            packageListStream
+                .bufferedReader()
+                .useLines { lines -> lines.partition { it.startsWith(DOKKA_PARAM_PREFIX) } }
+
+        val paramsMap = params.asSequence()
+            .map { it.removePrefix(DOKKA_PARAM_PREFIX).split(":", limit = 2) }
+            .groupBy({ (key, _) -> key }, { (_, value) -> value })
+
+        val format = paramsMap["format"]?.singleOrNull() ?: when {
+            jdk < 8 -> "javadoc1" // Covers JDK 1 - 7
+            jdk < 10 -> "javadoc8" // Covers JDK 8 - 9
+            else -> "javadoc10" // Covers JDK 10+
+        }
+
+        val locations = paramsMap["location"].orEmpty()
+            .map { it.split("\u001f", limit = 2) }
+            .map { (key, value) -> key to value }
+            .toMap()
+
+        val externalLocationProvider =
+            externalLocationProviderFactories.asSequence().map { it.getExternalLocationProvider(format) }
+                .filterNotNull().take(1).firstOrNull()
+
+        val info = DefaultLocationProvider.LocationInfo(
+            externalLocationProvider,
+            packages.toSet(),
+            locations
+        )
+        cache[url] = info
+        return info
+    }
+
+    private fun URL.doOpenConnectionToReadContent(timeout: Int = 10000, redirectsAllowed: Int = 16): URLConnection {
+        val connection = this.openConnection().apply {
+            connectTimeout = timeout
+            readTimeout = timeout
+        }
+
+        when (connection) {
+            is HttpURLConnection -> {
+                return when (connection.responseCode) {
+                    in 200..299 -> {
+                        connection
+                    }
+                    HttpURLConnection.HTTP_MOVED_PERM,
+                    HttpURLConnection.HTTP_MOVED_TEMP,
+                    HttpURLConnection.HTTP_SEE_OTHER -> {
+                        if (redirectsAllowed > 0) {
+                            val newUrl = connection.getHeaderField("Location")
+                            URL(newUrl).doOpenConnectionToReadContent(timeout, redirectsAllowed - 1)
+                        } else {
+                            throw RuntimeException("Too many redirects")
+                        }
+                    }
+                    else -> {
+                        throw RuntimeException("Unhandled http code: ${connection.responseCode}")
+                    }
+                }
+            }
+            else -> return connection
+        }
+    }
+
+    companion object {
+        const val DOKKA_PARAM_PREFIX = "\$dokka."
+    }
+
+}