2 files changed, 124 insertions, 0 deletions
diff --git a/buildSrc/build.gradle.kts b/buildSrc/build.gradle.kts
index 2239861b..e9d8587d 100644
--- a/buildSrc/build.gradle.kts
+++ b/buildSrc/build.gradle.kts
@@ -37,6 +37,10 @@ gradlePlugin {
       id = "versioning-plugin"
       implementationClass = "VersioningPlugin"
     }
+    register("psl") {
+      id = "psl-plugin"
+      implementationClass = "PublicSuffixListPlugin"
+    }
   }
 }
 
diff --git a/buildSrc/src/main/java/PublicSuffixListPlugin.kt b/buildSrc/src/main/java/PublicSuffixListPlugin.kt
new file mode 100644
index 00000000..df50f2b4
--- /dev/null
+++ b/buildSrc/src/main/java/PublicSuffixListPlugin.kt
@@ -0,0 +1,120 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import java.io.File
+import java.util.TreeSet
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okio.ByteString
+import okio.ByteString.Companion.encodeUtf8
+import okio.buffer
+import okio.sink
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+
+/**
+ * Gradle plugin to update the public suffix list used by the `lib-publicsuffixlist` component.
+ *
+ * Base on PublicSuffixListGenerator from OkHttp:
+ * https://github.com/square/okhttp/blob/master/okhttp/src/test/java/okhttp3/internal/publicsuffix/PublicSuffixListGenerator.java
+ */
+class PublicSuffixListPlugin : Plugin<Project> {
+  override fun apply(project: Project) {
+    project.tasks.register("updatePSL") {
+      doLast {
+        val filename = project.projectDir.absolutePath + "/src/main/assets/publicsuffixes"
+        updatePublicSuffixList(filename)
+      }
+    }
+  }
+
+  private fun updatePublicSuffixList(destination: String) {
+    val list = fetchPublicSuffixList()
+    writeListToDisk(destination, list)
+  }
+
+  private fun writeListToDisk(destination: String, data: PublicSuffixListData) {
+    val fileSink = File(destination).sink()
+
+    fileSink.buffer().use { sink ->
+      sink.writeInt(data.totalRuleBytes)
+
+      for (domain in data.sortedRules) {
+        sink.write(domain).writeByte('\n'.toInt())
+      }
+
+      sink.writeInt(data.totalExceptionRuleBytes)
+
+      for (domain in data.sortedExceptionRules) {
+        sink.write(domain).writeByte('\n'.toInt())
+      }
+    }
+  }
+
+  private fun fetchPublicSuffixList(): PublicSuffixListData {
+    val client = OkHttpClient.Builder().build()
+
+    val request =
+      Request.Builder().url("https://publicsuffix.org/list/public_suffix_list.dat").build()
+
+    client.newCall(request).execute().use { response ->
+      val source = requireNotNull(response.body).source()
+
+      val data = PublicSuffixListData()
+
+      while (!source.exhausted()) {
+        val line = source.readUtf8LineStrict()
+
+        if (line.trim { it <= ' ' }.isEmpty() || line.startsWith("//")) {
+          continue
+        }
+
+        if (line.contains(WILDCARD_CHAR)) {
+          assertWildcardRule(line)
+        }
+
+        var rule = line.encodeUtf8()
+
+        if (rule.startsWith(EXCEPTION_RULE_MARKER)) {
+          rule = rule.substring(1)
+          // We use '\n' for end of value.
+          data.totalExceptionRuleBytes += rule.size + 1
+          data.sortedExceptionRules.add(rule)
+        } else {
+          data.totalRuleBytes += rule.size + 1 // We use '\n' for end of value.
+          data.sortedRules.add(rule)
+        }
+      }
+
+      return data
+    }
+  }
+
+  @Suppress("TooGenericExceptionThrown", "ThrowsCount")
+  private fun assertWildcardRule(rule: String) {
+    if (rule.indexOf(WILDCARD_CHAR) != 0) {
+      throw RuntimeException("Wildcard is not not in leftmost position")
+    }
+
+    if (rule.indexOf(WILDCARD_CHAR, 1) != -1) {
+      throw RuntimeException("Rule contains multiple wildcards")
+    }
+
+    if (rule.length == 1) {
+      throw RuntimeException("Rule wildcards the first level")
+    }
+  }
+
+  companion object {
+    private const val WILDCARD_CHAR = "*"
+    private val EXCEPTION_RULE_MARKER = "!".encodeUtf8()
+  }
+}
+
+data class PublicSuffixListData(
+  var totalRuleBytes: Int = 0,
+  var totalExceptionRuleBytes: Int = 0,
+  val sortedRules: TreeSet<ByteString> = TreeSet(),
+  val sortedExceptionRules: TreeSet<ByteString> = TreeSet()
+)