Feature: Separate install path from download path and add polling rate to chunk download listener

javasteam-depotdownloader/src/main/kotlin/in/dragonbra/javasteam/depotdownloader/DepotDownloader.kt

@@ -156,6 +156,8 @@ class DepotDownloader @JvmOverloads constructor(
 
     private val progressUpdateInterval = 500L // ms
 
+    private var lastProgressUpdate = 0L
+
     private val scope: CoroutineScope = CoroutineScope(Dispatchers.IO + SupervisorJob(parentJob))
 
     private var cdnClientPool: CDNClientPool? = null
@@ -211,6 +213,7 @@ class DepotDownloader @JvmOverloads constructor(
         val androidEmulation: Boolean = false,
         val downloadManifestOnly: Boolean = false,
         val installToGameNameDirectory: Boolean = false,
+        val downloadPath: Path? = null,
 
         // Not used yet in code
         val usingFileList: Boolean = false,
@@ -1571,7 +1574,8 @@ class DepotDownloader @JvmOverloads constructor(
         ensureActive()
 
         // Create temporary file path for this chunk
-        val chunkTempDir = depot.installDir / STAGING_DIR / "chunks" / fileId
+        // Try to set it to the Download path, use installdir as fallback
+        val chunkTempDir = (config.downloadPath ?: depot.installDir) / STAGING_DIR / "chunks" / fileId
         filesystem.createDirectories(chunkTempDir)
         val chunkTempPath = chunkTempDir / "${chunk.offset}_$chunkID.chunk"
 
@@ -1745,6 +1749,8 @@ class DepotDownloader @JvmOverloads constructor(
                     }
 
                     is AppItem -> {
+                        config = config.copy(downloadPath = item.downloadDirectory?.toPath())
+
                         val branch = item.branch ?: DEFAULT_BRANCH
                         config = config.copy(betaPassword = item.branchPassword)
 
@@ -1835,7 +1841,7 @@ class DepotDownloader @JvmOverloads constructor(
         val file = item.file
         val fileFinalPath = depot.installDir / file.fileName
         val chunk = item.chunk
-        val chunkTempDir = depot.installDir / STAGING_DIR / "chunks" / item.fileId
+        val chunkTempDir = (config.downloadPath ?: depot.installDir) / STAGING_DIR / "chunks" / item.fileId
 
         val writeOffset = file.chunks.filter { it.offset < chunk.offset }.sumOf { it.uncompressedLength.toLong() }
 
@@ -1888,14 +1894,19 @@ class DepotDownloader @JvmOverloads constructor(
             }
 
             val depotPercentage = (sizeDownloaded.toFloat() / depotDownloadCounter.completeDownloadSize)
-
-            notifyListeners { listener ->
-                listener.onChunkCompleted(
-                    depotId = depot.depotId,
-                    depotPercentComplete = depotPercentage,
-                    compressedBytes = downloadCounter.totalBytesCompressed,
-                    uncompressedBytes = downloadCounter.totalBytesUncompressed
-                )
+            // Limiting the listener calls to once every 0.5s significantly improves performance on SD cards
+            val now = System.currentTimeMillis()
+            if (now - lastProgressUpdate >= progressUpdateInterval) {
+                lastProgressUpdate = now
+                logger?.debug("Chunk progress update")
+                notifyListeners { listener ->
+                    listener.onChunkCompleted(
+                        depotId = depot.depotId,
+                        depotPercentComplete = depotPercentage,
+                        compressedBytes = downloadCounter.totalBytesCompressed,
+                        uncompressedBytes = downloadCounter.totalBytesUncompressed
+                    )
+                }
             }
 
             val remainingDownloads = item.fileStreamData.chunksDownloaded.decrementAndGet()

javasteam-depotdownloader/src/main/kotlin/in/dragonbra/javasteam/depotdownloader/data/DownloadItems.kt

@@ -70,6 +70,7 @@ class PubFileItem @JvmOverloads constructor(
  * @property lowViolence If true, downloads low-violence versions where available
  * @property depot List of specific depot IDs to download
  * @property manifest List of specific manifest IDs corresponding to depot IDs
+ * @property downloadDirectory Separate directory for downloading and staging an app/game
  *
  * @author Lossy
  * @since Oct 1, 2025
@@ -89,6 +90,7 @@ class AppItem @JvmOverloads constructor(
     val lowViolence: Boolean = false,
     val depot: List<Int> = emptyList(),
     val manifest: List<Long> = emptyList(),
+    val downloadDirectory: String? = null,
     verify: Boolean = false,
     downloadManifestOnly: Boolean = false,
 ) : DownloadItem(appId, installDirectory, installToGameNameDirectory, verify, downloadManifestOnly)

javasteam-samples/src/main/java/in/dragonbra/javasteamsamples/_023_downloadapp/SampleDownloadApp.java

@@ -290,6 +290,7 @@ private void downloadApp() {
                     /* (Optional) lowViolence */ false,
                     /* (Optional) depot */ List.of(),
                     /* (Optional) manifest */ List.of(),
+                    /* (Optional) downloadDirectory */ null,
                     /* (Optional) verify */ false,
                     /* (Optional) downloadManifestOnly */ false
             );