google#5376 Add conversion from reader to inputstream

louiscb · Mar 1, 2022 · 0d81773 · 0d81773
1 parent ac11adc
commit 0d81773
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Showing 2 changed files with 111 additions and 12 deletions.
diff --git a/guava-tests/test/com/google/common/io/CharStreamsTest.java b/guava-tests/test/com/google/common/io/CharStreamsTest.java
@@ -16,16 +16,15 @@
 
 package com.google.common.io;
 
+import com.google.common.base.Charsets;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
-import java.io.EOFException;
-import java.io.FilterReader;
-import java.io.IOException;
-import java.io.Reader;
-import java.io.StringReader;
-import java.io.StringWriter;
-import java.io.Writer;
+
+import java.io.*;
 import java.nio.CharBuffer;
+import java.nio.charset.CodingErrorAction;
+import java.nio.charset.StandardCharsets;
+import java.nio.charset.UnmappableCharacterException;
 import java.util.List;
 
 /**
@@ -193,6 +192,47 @@ public void testCopy_toStringBuilder_fromReadable() throws IOException {
     assertEquals(I18N.length(), copied);
   }
 
+  public void testAsInputStream_fromReader() throws IOException {
+    Reader reader = new StringReader(TEXT);
+
+    InputStream inputStream = CharStreams.asInputStream(reader, Charsets.UTF_8);
+    String inputStreamString = getInputStreamString(inputStream);
+
+    assertEquals(TEXT, inputStreamString);
+  }
+
+  public void testAsInputStream_fromReader_withBufferSize() throws IOException {
+    Reader reader = new StringReader(TEXT);
+
+    InputStream inputStream = CharStreams.asInputStream(reader, Charsets.UTF_8, 100);
+    String inputStreamString = getInputStreamString(inputStream);
+
+    assertEquals(TEXT, inputStreamString);
+  }
+
+  public void testAsInputStream_fromReader_withBufferSizeAndCodingErrorAction() throws IOException {
+    Reader reader = new StringReader(TEXT);
+
+    CodingErrorAction codingErrorAction = CodingErrorAction.REPORT;
+    InputStream inputStream = CharStreams.asInputStream(reader, Charsets.US_ASCII, 100, codingErrorAction);
+    String inputStreamString = getInputStreamString(inputStream);
+
+    assertEquals(TEXT, inputStreamString);
+  }
+
+  public void testAsInputStream_fromReader_withBufferSizeAndCodingErrorActionWithMalformedText() throws IOException {
+    String malformedText = "ÏíÓãÈÑ";
+    Reader reader = new StringReader(malformedText);
+    CodingErrorAction codingErrorAction = CodingErrorAction.REPORT;
+    InputStream inputStream = CharStreams.asInputStream(reader, Charsets.US_ASCII, 100, codingErrorAction);
+
+    try {
+      getInputStreamString(inputStream);
+      fail();
+    } catch (UnmappableCharacterException e) {
+    }
+  }
+
   public void testCopy_toWriter_fromReader() throws IOException {
     StringWriter writer = new StringWriter();
     long copied = CharStreams.copy(new StringReader(ASCII), writer);
@@ -339,4 +379,16 @@ public int read(CharBuffer cb) throws IOException {
       }
     };
   }
+
+  private static String getInputStreamString(InputStream inputStream) throws IOException {
+    char[] buffer = new char[CharStreams.BUFFER_SIZE_INPUT_STREAM];
+    Reader input = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
+    StringBuilder output = new StringBuilder();
+
+    for (int numRead; (numRead = input.read(buffer, 0, buffer.length)) != -1; ) {
+      output.append(buffer, 0, numRead);
+    }
+
+    return output.toString();
+  }
 }
diff --git a/guava/src/com/google/common/io/CharStreams.java b/guava/src/com/google/common/io/CharStreams.java
@@ -20,12 +20,11 @@
 import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtIncompatible;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
-import java.io.Closeable;
-import java.io.EOFException;
-import java.io.IOException;
-import java.io.Reader;
-import java.io.Writer;
+
+import java.io.*;
 import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CodingErrorAction;
 import java.util.ArrayList;
 import java.util.List;
 import javax.annotation.CheckForNull;
@@ -49,6 +48,7 @@ public final class CharStreams {
 
   // 2K chars (4K bytes)
   private static final int DEFAULT_BUF_SIZE = 0x800;
+  public static final int BUFFER_SIZE_INPUT_STREAM = 8192;
 
   /** Creates a new {@code CharBuffer} for buffering reads or writes. */
   static CharBuffer createBuffer() {
@@ -182,6 +182,53 @@ private static StringBuilder toStringBuilder(Readable r) throws IOException {
     return sb;
   }
 
+  /**
+   * Converts a Reader object into a InputStream using the provided Charset.
+   * Does not close the {@code Reader}. Defaults to a standard buffer size for the input stream.
+   *
+   * @param reader the reader to convert
+   * @param charset the encoding charset
+   * @return a {@link InputStream} containing all the reader's contents
+   */
+  public static InputStream asInputStream(Reader reader, Charset charset) {
+    return new ReaderInputStream(reader,
+            charset,
+            BUFFER_SIZE_INPUT_STREAM);
+  }
+
+  /**
+   * Converts a Reader object into a InputStream using the provided Charset and buffer size.
+   * Does not close the {@code Reader}.
+   *
+   * @param reader the reader to convert
+   * @param charset the encoding charset
+   * @param bufferSize the buffer size of the input stream
+   * @return a {@link InputStream} containing all the reader's contents
+   */
+  public static InputStream asInputStream(Reader reader, Charset charset, int bufferSize) {
+    return new ReaderInputStream(reader,
+            charset,
+            bufferSize);
+  }
+
+  /**
+   * Converts a Reader object into a InputStream using the provided Charset and buffer size.
+   * Performs a specified action on malformed input.
+   * Does not close the {@code Reader}.
+   *
+   * @param reader the reader to convert
+   * @param charset the encoding charset
+   * @param bufferSize the buffer size of the input stream
+   * @param newAction the action to take on malformed input and unmappable characters
+   * @return a {@link InputStream} containing all the reader's contents
+   */
+  public static InputStream asInputStream(Reader reader, Charset charset, int bufferSize,
+                                          CodingErrorAction newAction) {
+    return new ReaderInputStream(reader,
+            charset.newEncoder().onMalformedInput(newAction).onUnmappableCharacter(newAction),
+            bufferSize);
+  }
+
   /**
    * Reads all of the lines from a {@link Readable} object. The lines do not include
    * line-termination characters, but do include other leading and trailing whitespace.