lib: refactor the GgufMetadataReader to take InputStream instead of absolute path as argument

examples/llama.android/app/src/main/java/com/example/llama/data/repo/ModelRepository.kt

@@ -208,9 +208,10 @@ class ModelRepositoryImpl @Inject constructor(
 
             // Extract GGUF metadata if possible
             val metadata = try {
-                val filePath = modelFile.absolutePath
+                Log.i(TAG, "Extracting GGUF Metadata from ${modelFile.absolutePath}")
-                Log.i(TAG, "Extracting GGUF Metadata from $filePath")
+                modelFile.inputStream().buffered().use {
-                GgufMetadata.fromDomain(ggufMetadataReader.readStructuredMetadata(filePath))
+                    GgufMetadata.fromDomain(ggufMetadataReader.readStructuredMetadata(it))
+                }
             } catch (e: Exception) {
                 Log.e(TAG, "Cannot extract GGUF metadata: ${e.message}", e)
                 throw e

examples/llama.android/llama/src/main/java/android/llama/cpp/gguf/GgufMetadataReader.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import android.llama.cpp.internal.gguf.GgufMetadataReaderImpl
 import android.net.Uri
 import java.io.IOException
+import java.io.InputStream
 
 /**
  * Interface for reading GGUF metadata from model files.
@@ -23,12 +24,12 @@ interface GgufMetadataReader {
     /**
      * Reads and parses GGUF metadata from the specified file path.
      *
-     * @param path The absolute path to the GGUF file
+     * @param input the [InputStream] obtained from a readable file or content
      * @return Structured metadata extracted from the file
      * @throws IOException if file is damaged or cannot be read
      * @throws InvalidFileFormatException if file format is invalid
      */
-    suspend fun readStructuredMetadata(path: String): GgufMetadata
+    suspend fun readStructuredMetadata(input: InputStream): GgufMetadata
 
     companion object {
         private val DEFAULT_SKIP_KEYS = setOf(

examples/llama.android/llama/src/main/java/android/llama/cpp/internal/gguf/GgufMetadataReaderImpl.kt

@@ -5,7 +5,6 @@ import android.llama.cpp.gguf.GgufMetadata
 import android.llama.cpp.gguf.GgufMetadataReader
 import android.llama.cpp.gguf.InvalidFileFormatException
 import android.net.Uri
-import java.io.File
 import java.io.IOException
 import java.io.InputStream
 
@@ -79,10 +78,10 @@ internal class GgufMetadataReaderImpl(
         context.contentResolver.openInputStream(uri)?.buffered()?.use { ensureMagic(it) } == true
 
     /** Reads the 4‑byte magic; throws if magic ≠ "GGUF". */
-    private fun ensureMagic(input: InputStream): Boolean {
+    private fun ensureMagic(input: InputStream): Boolean =
-        val magic = ByteArray(4)
+        ByteArray(4).let {
-        if (input.read(magic) != 4) throw IOException("Not a valid file!")
+            if (input.read(it) != 4) throw IOException("Not a valid file!")
-        return magic.contentEquals(byteArrayOf(0x47, 0x47, 0x55, 0x46)) // "GGUF"
+            it.contentEquals(byteArrayOf(0x47, 0x47, 0x55, 0x46)) // "GGUF"
         }
 
     /**
@@ -106,8 +105,7 @@ internal class GgufMetadataReaderImpl(
      * @throws IOException if the file is not GGUF, the version is unsupported,
      *         or the metadata block is truncated / corrupt.
      */
-    override suspend fun readStructuredMetadata(path: String): GgufMetadata {
+    override suspend fun readStructuredMetadata(input: InputStream): GgufMetadata {
-        File(path).inputStream().buffered().use { input ->
         // ── 1. header ──────────────────────────────────────────────────────────
         // throws on mismatch
         val version       = ensureMagicAndVersion(input)
@@ -120,7 +118,6 @@ internal class GgufMetadataReaderImpl(
         // ── 3. build structured object ────────────────────────────────────────
         return buildStructured(meta, version, tensorCount, kvCount)
     }
-    }
 
     /** Reads the 4‑byte magic + 4‑byte version; throws if magic ≠ "GGUF". */
     private fun ensureMagicAndVersion(input: InputStream): GgufMetadata.GgufVersion {
@@ -153,18 +150,17 @@ internal class GgufMetadataReaderImpl(
      * The function honours [skipKeys] and [arraySummariseThreshold] by invoking
      * [skipValue] or [parseValue] accordingly.
      */
-    private fun readMetaMap(input: InputStream, kvCnt: Long): Map<String, MetadataValue> {
+    private fun readMetaMap(input: InputStream, kvCnt: Long): Map<String, MetadataValue> =
-        val map = mutableMapOf<String, MetadataValue>()
+        mutableMapOf<String, MetadataValue>().apply {
              repeat(kvCnt.toInt()) {
                  val key = readString(input)
                  val valueT = MetadataType.fromCode(littleEndianBytesToInt(input.readNBytesExact(4)))
                  if (key in skipKeys) {
                      skipValue(input, valueT)
                  } else {
-                map[key] = parseValue(input, valueT)
+                     this[key] = parseValue(input, valueT)
                  }
              }
-        return map
          }
 
     /**
@@ -509,25 +505,25 @@ internal class GgufMetadataReaderImpl(
     }
 
     /** Helper: Read a GGUF string from the stream (8-byte length followed by UTF-8 bytes). */
-    private fun readString(input: InputStream): String {
+    private fun readString(input: InputStream): String =
         // Read 8-byte little-endian length (number of bytes in the string).
-        val len = readLittleLong(input)
+        readLittleLong(input).let { len ->
             if (len < 0 || len > Int.MAX_VALUE) throw IOException("String too long: $len")
 
             // Read the UTF-8 bytes of the given length.
-        val buf = ByteArray(len.toInt())
+            ByteArray(len.toInt()).let {
-        if (buf.isNotEmpty()) input.readFully(buf)
+                if (it.isNotEmpty()) input.readFully(it)
-        return String(buf, Charsets.UTF_8)
+                String(it, Charsets.UTF_8)
+            }
         }
 
     /** Helper: Convert a 4-byte little-endian byte array to a 32-bit integer. */
-    private fun littleEndianBytesToInt(bytes: ByteArray): Int {
+    private fun littleEndianBytesToInt(bytes: ByteArray): Int =
         // Note: assumes bytes length is 4.
-        return (bytes[3].toInt() and 0xFF shl 24) or
+        (bytes[3].toInt() and 0xFF shl 24) or
             (bytes[2].toInt() and 0xFF shl 16) or
             (bytes[1].toInt() and 0xFF shl 8) or
             (bytes[0].toInt() and 0xFF)
-    }
 
     /**
      * Robust skip that works the same on JDK 11 and Android’s desugared runtime.
@@ -577,9 +573,7 @@ internal class GgufMetadataReaderImpl(
      *
      * @throws IOException on premature EOF.
      */
-    private fun InputStream.readNBytesExact(n: Int): ByteArray {
+    private fun InputStream.readNBytesExact(n: Int) = ByteArray(n).also {
-        val buf = ByteArray(n)
+        if (read(it) != n) throw IOException("Unexpected EOF")
-        if (read(buf) != n) throw IOException("Unexpected EOF")
-        return buf
     }
 }