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fenix/app/src/main/java/org/mozilla/fenix/settings/about/AboutLibrariesActivity.kt

121 lines
4.8 KiB
Kotlin

/* 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/. */
package org.mozilla.fenix.settings.about
import android.graphics.Typeface
import android.os.Bundle
import android.text.util.Linkify
import android.widget.ArrayAdapter
import android.widget.ListView
import android.widget.TextView
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatActivity
import org.mozilla.fenix.R
import java.nio.charset.Charset
import java.util.Locale
/**
* Displays the licenses of all the libraries used by Fenix.
*
* This is a re-implementation of play-services-oss-licenses library.
* We can't use the official implementation in the OSS flavor of Fenix
* because it is proprietary and closed-source.
*
* There are popular FLOSS alternatives to Google's plugin and library
* such as AboutLibraries (https://github.com/mikepenz/AboutLibraries)
* but we considered the risk of introducing such third-party dependency
* to Fenix too high. Therefore, we use Google's gradle plugin to
* extract the dependencies and their licenses, and this activity
* to show the extracted licenses to the end-user.
*/
class AboutLibrariesActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val appName = getString(R.string.app_name)
title = getString(R.string.open_source_licenses_title, appName)
setContentView(R.layout.about_libraries_activity)
setSupportActionBar(findViewById(R.id.toolbar))
supportActionBar?.setDisplayHomeAsUpEnabled(true)
supportActionBar?.setDisplayShowHomeEnabled(true)
setupLibrariesListView()
}
override fun onSupportNavigateUp(): Boolean {
onBackPressed()
return true
}
private fun setupLibrariesListView() {
val libraries = parseLibraries()
val listView = findViewById<ListView>(R.id.about_libraries_listview)
listView.adapter = ArrayAdapter(this, android.R.layout.simple_list_item_1, libraries)
listView.setOnItemClickListener { _, _, position, _ ->
showLicenseDialog(libraries[position])
}
}
private fun parseLibraries(): List<LibraryItem> {
/*
The gradle plugin "oss-licenses-plugin" creates two "raw" resources:
- third_party_licenses which is the binary concatenation of all the licenses text for
all the libraries. License texts can either be an URL to a license file or just the
raw text of the license.
- third_party_licenses_metadata which contains one dependency per line formatted in
the following way: "[start_offset]:[length] [name]"
[start_offset] : first byte in third_party_licenses that contains the license
text for this library.
[length] : length of the license text for this library in
third_party_licenses.
[name] : either the name of the library, or its artifact name.
See https://github.com/google/play-services-plugins/tree/master/oss-licenses-plugin
*/
val licensesData = resources
.openRawResource(R.raw.third_party_licenses)
.readBytes()
val licensesMetadataReader = resources
.openRawResource(R.raw.third_party_license_metadata)
.bufferedReader()
return licensesMetadataReader.use { reader -> reader.readLines() }.map { line ->
val (section, name) = line.split(" ", limit = 2)
val (startOffset, length) = section.split(":", limit = 2).map(String::toInt)
val licenseData = licensesData.sliceArray(startOffset until startOffset + length)
val licenseText = licenseData.toString(Charset.forName("UTF-8"))
LibraryItem(name, licenseText)
}.sortedBy { item -> item.name.toLowerCase(Locale.ROOT) }
}
private fun showLicenseDialog(libraryItem: LibraryItem) {
val dialog = AlertDialog.Builder(this)
.setTitle(libraryItem.name)
.setMessage(libraryItem.license)
.create()
dialog.show()
val textView = dialog.findViewById<TextView>(android.R.id.message)!!
Linkify.addLinks(textView, Linkify.ALL)
textView.linksClickable = true
textView.textSize = LICENSE_TEXT_SIZE
textView.typeface = Typeface.MONOSPACE
}
companion object {
private const val LICENSE_TEXT_SIZE = 10F
}
}
private class LibraryItem(val name: String, val license: String) {
override fun toString(): String {
return name
}
}