src/main/kotlin/net/pterodactylus/sone/core/DefaultElementLoader.kt

   1 package net.pterodactylus.sone.core
   2
   3 import com.google.common.base.Ticker
   4 import com.google.common.cache.Cache
   5 import com.google.common.cache.CacheBuilder
   6 import freenet.keys.FreenetURI
   7 import java.io.ByteArrayInputStream
   8 import java.net.URLDecoder
   9 import java.text.Normalizer
  10 import java.util.concurrent.TimeUnit.MINUTES
  11 import javax.imageio.ImageIO
  12 import javax.inject.Inject
  13
  14 /**
  15  * [ElementLoader] implementation that uses a simple Guava [com.google.common.cache.Cache].
  16  */
  17 class DefaultElementLoader(private val freenetInterface: FreenetInterface, ticker: Ticker) : ElementLoader {
  18
  19         @Inject constructor(freenetInterface: FreenetInterface) : this(freenetInterface, Ticker.systemTicker())
  20
  21         private val loadingLinks: Cache<String, Boolean> = CacheBuilder.newBuilder().build<String, Boolean>()
  22         private val failureCache: Cache<String, Boolean> = CacheBuilder.newBuilder().ticker(ticker).expireAfterWrite(30, MINUTES).build<String, Boolean>()
  23         private val imageCache: Cache<String, LinkedElement> = CacheBuilder.newBuilder().build<String, LinkedElement>()
  24         private val callback = object : FreenetInterface.BackgroundFetchCallback {
  25                 override fun shouldCancel(uri: FreenetURI, mimeType: String, size: Long): Boolean {
  26                         return !mimeType.startsWith("image/") || (size > 2097152)
  27                 }
  28
  29                 override fun loaded(uri: FreenetURI, mimeType: String, data: ByteArray) {
  30                         if (!mimeType.startsWith("image/")) {
  31                                 return
  32                         }
  33                         ByteArrayInputStream(data).use {
  34                                 ImageIO.read(it)
  35                         }?.let {
  36                                 imageCache.get(uri.toString().decode().normalize()) {
  37                                         LinkedElement(uri.toString(), properties = mapOf("size" to data.size, "sizeHuman" to data.size.human))
  38                                 }
  39                         }
  40                         removeLoadingLink(uri)
  41                 }
  42
  43                 private val Int.human get() = when (this) {
  44                         in 0..1023 -> "$this B"
  45                         in 1024..1048575 -> "${this / 1024} KiB"
  46                         in 1048576..1073741823 -> "${this / 1048576} MiB"
  47                         else -> "${this / 1073741824} GiB"
  48                 }
  49
  50                 override fun failed(uri: FreenetURI) {
  51                         failureCache.put(uri.toString().decode().normalize(), true)
  52                         removeLoadingLink(uri)
  53                 }
  54
  55                 private fun removeLoadingLink(uri: FreenetURI) {
  56                         synchronized(loadingLinks) {
  57                                 loadingLinks.invalidate(uri.toString().decode().normalize())
  58                         }
  59                 }
  60         }
  61
  62         override fun loadElement(link: String): LinkedElement {
  63                 val normalizedLink = link.decode().normalize()
  64                 synchronized(loadingLinks) {
  65                         imageCache.getIfPresent(normalizedLink)?.run {
  66                                 return this
  67                         }
  68                         failureCache.getIfPresent(normalizedLink)?.run {
  69                                 return LinkedElement(link, failed = true)
  70                         }
  71                         if (loadingLinks.getIfPresent(normalizedLink) == null) {
  72                                 loadingLinks.put(normalizedLink, true)
  73                                 freenetInterface.startFetch(FreenetURI(link), callback)
  74                         }
  75                 }
  76                 return LinkedElement(link, loading = true)
  77         }
  78
  79         private fun String.decode() = URLDecoder.decode(this, "UTF-8")!!
  80         private fun String.normalize() = Normalizer.normalize(this, Normalizer.Form.NFC)!!
  81
  82 }