Rename TruncatingInputStream -> LimitedInputStream.

core-util-jvm/src/main/java/org/signal/core/util/stream/LimitedInputStream.kt

@@ -15,21 +15,22 @@ import kotlin.math.min
 /**
  * An [InputStream] that will read from the target [InputStream] until it reaches the end, or until it has read [maxBytes] bytes.
  */
-class TruncatingInputStream(private val wrapped: InputStream, private val maxBytes: Long) : FilterInputStream(wrapped) {
+class LimitedInputStream(private val wrapped: InputStream, private val maxBytes: Long) : FilterInputStream(wrapped) {
 
-  private var bytesRead: Long = 0
+  private var totalBytesRead: Long = 0
   private var lastMark = -1L
 
   override fun read(): Int {
-    if (bytesRead >= maxBytes) {
+    if (totalBytesRead >= maxBytes) {
       return -1
     }
 
-    return wrapped.read().also {
-      if (it >= 0) {
-        bytesRead++
-      }
+    val read = wrapped.read()
+    if (read >= 0) {
+      totalBytesRead++
     }
+
+    return read
   }
 
   override fun read(destination: ByteArray): Int {
@@ -37,34 +38,33 @@ class TruncatingInputStream(private val wrapped: InputStream, private val maxByt
   }
 
   override fun read(destination: ByteArray, offset: Int, length: Int): Int {
-    if (bytesRead >= maxBytes) {
+    if (totalBytesRead >= maxBytes) {
       return -1
     }
 
-    val bytesRemaining: Long = maxBytes - bytesRead
-    val bytesToRead: Int = if (bytesRemaining > length) length else Math.toIntExact(bytesRemaining)
+    val bytesRemaining: Long = maxBytes - totalBytesRead
+    val bytesToRead: Int = min(length, Math.toIntExact(bytesRemaining))
     val bytesRead = wrapped.read(destination, offset, bytesToRead)
 
     if (bytesRead > 0) {
-      this.bytesRead += bytesRead
+      totalBytesRead += bytesRead
     }
 
     return bytesRead
   }
 
   override fun skip(requestedSkipCount: Long): Long {
-    val bytesRemaining: Long = maxBytes - bytesRead
+    val bytesRemaining: Long = maxBytes - totalBytesRead
     val bytesToSkip: Long = min(bytesRemaining, requestedSkipCount)
+    val skipCount = super.skip(bytesToSkip)
 
-    return super.skip(bytesToSkip).also { bytesSkipped ->
-      if (bytesSkipped > 0) {
-        this.bytesRead += bytesSkipped
-      }
-    }
+    totalBytesRead += skipCount
+
+    return skipCount
   }
 
   override fun available(): Int {
-    val bytesRemaining = Math.toIntExact(maxBytes - bytesRead)
+    val bytesRemaining = Math.toIntExact(maxBytes - totalBytesRead)
     return min(bytesRemaining, wrapped.available())
   }
 
@@ -78,7 +78,7 @@ class TruncatingInputStream(private val wrapped: InputStream, private val maxByt
     }
 
     wrapped.mark(readlimit)
-    lastMark = bytesRead
+    lastMark = totalBytesRead
   }
 
   override fun reset() {
@@ -91,7 +91,7 @@ class TruncatingInputStream(private val wrapped: InputStream, private val maxByt
     }
 
     wrapped.reset()
-    bytesRead = lastMark
+    totalBytesRead = lastMark
   }
 
   /**
@@ -100,6 +100,10 @@ class TruncatingInputStream(private val wrapped: InputStream, private val maxByt
    * @param byteLimit The maximum number of truncated bytes to read. Defaults to no limit.
    */
   fun readTruncatedBytes(byteLimit: Int = -1): ByteArray {
+    if (totalBytesRead < maxBytes) {
+      throw IllegalStateException("Stream has not been fully read")
+    }
+
     return if (byteLimit < 0) {
       wrapped.readFully()
     } else {

core-util-jvm/src/test/java/org/signal/core/util/stream/LimitedInputStreamTest.kt

@@ -10,11 +10,11 @@ import org.junit.Test
 import org.signal.core.util.readFully
 import org.signal.core.util.readNBytesOrThrow
 
-class TruncatingInputStreamTest {
+class LimitedInputStreamTest {
 
   @Test
   fun `when I fully read the stream via a buffer, I should only get maxBytes`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
     val data = inputStream.readFully()
 
     assertEquals(75, data.size)
@@ -22,7 +22,7 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I fully read the stream one byte at a time, I should only get maxBytes`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
 
     var count = 0
     var lastRead = inputStream.read()
@@ -36,7 +36,7 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I skip past the maxBytes, I should get -1`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
 
     val skipCount = inputStream.skip(100)
     val read = inputStream.read()
@@ -47,7 +47,7 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I skip, I should still truncate correctly afterwards`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
 
     val skipCount = inputStream.skip(50)
     val data = inputStream.readFully()
@@ -58,7 +58,7 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I skip more than maxBytes, I only skip maxBytes`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
 
     val skipCount = inputStream.skip(100)
 
@@ -67,7 +67,7 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I finish reading the stream, getTruncatedBytes gives me the rest`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
     inputStream.readFully()
 
     val truncatedBytes = inputStream.readTruncatedBytes()
@@ -76,16 +76,22 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I finish reading the stream, getTruncatedBytes gives me the rest, respecting the byte limit`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
     inputStream.readFully()
 
     val truncatedBytes = inputStream.readTruncatedBytes(byteLimit = 10)
     assertEquals(10, truncatedBytes.size)
   }
 
+  @Test(expected = IllegalStateException::class)
+  fun `if I have not finished reading the stream, getTruncatedBytes throws IllegalStateException`() {
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    inputStream.readTruncatedBytes()
+  }
+
   @Test
   fun `when I call available, it should respect the maxBytes`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
     val available = inputStream.available()
 
     assertEquals(75, available)
@@ -93,7 +99,7 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I call available after reading some bytes, it should respect the maxBytes`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
     inputStream.readNBytesOrThrow(50)
 
     val available = inputStream.available()
@@ -103,7 +109,7 @@ class TruncatingInputStreamTest {
 
   @Test
   fun `when I mark and reset, it should jump back to the correct position`() {
-    val inputStream = TruncatingInputStream(ByteArray(100).inputStream(), maxBytes = 75)
+    val inputStream = LimitedInputStream(ByteArray(100).inputStream(), maxBytes = 75)
 
     inputStream.mark(100)
     inputStream.readNBytesOrThrow(10)