Feature/pr214 Appendable to output and error streams - changes (#304)

* FEAT Define Appendable to read input and error streams of ffmpeg/ffprobe process

Co-authored-by: Mickael GREGORI <[email protected]>

src/main/java/net/bramp/ffmpeg/FFcommon.java

@@ -8,6 +8,7 @@
 import com.google.common.io.CharStreams;
 import java.io.BufferedReader;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
@@ -28,6 +29,12 @@ abstract class FFcommon {
   /** Version string */
   String version = null;
 
+  /** Process input stream */
+  Appendable processOutputStream = System.out;
+
+  /** Process error stream */
+  Appendable processErrorStream = System.err;
+
   public FFcommon(@Nonnull String path) {
     this(path, new RunProcessFunction());
   }
@@ -38,8 +45,26 @@ protected FFcommon(@Nonnull String path, @Nonnull ProcessFunction runFunction) {
     this.path = path;
   }
 
+  public void setProcessOutputStream(@Nonnull Appendable processOutputStream) {
+    Preconditions.checkNotNull(processOutputStream);
+    this.processOutputStream = processOutputStream;
+  }
+
+  public void setProcessErrorStream(@Nonnull Appendable processErrorStream) {
+    Preconditions.checkNotNull(processErrorStream);
+    this.processErrorStream = processErrorStream;
+  }
+
+  private BufferedReader _wrapInReader(final InputStream inputStream) {
+    return new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
+  }
+
   protected BufferedReader wrapInReader(Process p) {
-    return new BufferedReader(new InputStreamReader(p.getInputStream(), StandardCharsets.UTF_8));
+    return _wrapInReader(p.getInputStream());
+  }
+
+  protected BufferedReader wrapErrorInReader(Process p) {
+    return _wrapInReader(p.getErrorStream());
   }
 
   protected void throwOnError(Process p) throws IOException {
@@ -107,8 +132,8 @@ public void run(List<String> args) throws IOException {
       // TODO Move the copy onto a thread, so that FFmpegProgressListener can be on this thread.
 
       // Now block reading ffmpeg's stdout. We are effectively throwing away the output.
-      CharStreams.copy(wrapInReader(p), System.out); // TODO Should I be outputting to stdout?
-
+      CharStreams.copy(wrapInReader(p), processOutputStream);
+      CharStreams.copy(wrapErrorInReader(p), processErrorStream);
       throwOnError(p);
 
     } finally {

src/test/java/net/bramp/ffmpeg/FFmpegTest.java

@@ -7,6 +7,8 @@
 
 import java.io.IOException;
 import java.util.List;
+
+import com.google.common.collect.Lists;
 import net.bramp.ffmpeg.fixtures.Codecs;
 import net.bramp.ffmpeg.fixtures.Filters;
 import net.bramp.ffmpeg.fixtures.Formats;
@@ -35,6 +37,8 @@ public void before() throws IOException {
     when(runFunc.run(argThatHasItem("-codecs"))).thenAnswer(new NewProcessAnswer("ffmpeg-codecs"));
     when(runFunc.run(argThatHasItem("-pix_fmts")))
         .thenAnswer(new NewProcessAnswer("ffmpeg-pix_fmts"));
+    when(runFunc.run(argThatHasItem("toto.mp4")))
+        .thenAnswer(new NewProcessAnswer("ffmpeg-version", "ffmpeg-no-such-file"));
     when(runFunc.run(argThatHasItem("-filters")))
         .thenAnswer(new NewProcessAnswer("ffmpeg-filters"));
 
@@ -72,6 +76,21 @@ public void testFormats() throws IOException {
     verify(runFunc, times(1)).run(argThatHasItem("-formats"));
   }
 
+  @Test
+  public void testReadProcessStreams() throws IOException {
+    // process input stream
+    Appendable processInputStream = mock(Appendable.class);
+    ffmpeg.setProcessOutputStream(processInputStream);
+    // process error stream
+    Appendable processErrStream = mock(Appendable.class);
+    ffmpeg.setProcessErrorStream(processErrStream);
+    // run ffmpeg with non existing file
+    ffmpeg.run(Lists.newArrayList("-i", "toto.mp4"));
+    // check calls to Appendables
+    verify(processInputStream, times(1)).append(any(CharSequence.class));
+    verify(processErrStream, times(1)).append(any(CharSequence.class));
+  }
+
   @Test
   public void testPixelFormat() throws IOException {
     // Run twice, the second should be cached

src/test/java/net/bramp/ffmpeg/lang/NewProcessAnswer.java

@@ -7,12 +7,21 @@
 public class NewProcessAnswer implements Answer<Process> {
   final String resource;
 
+  final String errResource;
+
   public NewProcessAnswer(String resource) {
+    this(resource, null);
+  }
+
+  public NewProcessAnswer(String resource, String errResource) {
     this.resource = resource;
+    this.errResource = errResource;
   }
 
   @Override
   public Process answer(InvocationOnMock invocationOnMock) throws Throwable {
-    return new MockProcess(Helper.loadResource(resource));
+    return errResource == null
+        ? new MockProcess(Helper.loadResource(resource))
+        : new MockProcess(null, Helper.loadResource(resource), Helper.loadResource(errResource));
   }
 }

src/test/resources/net/bramp/ffmpeg/fixtures/ffmpeg-no-such-file

@@ -0,0 +1 @@
+toto.mp4: No such file or directory