Merge "Add util methods to read partial files." into android10-dev
diff --git a/src/com/android/tradefed/util/FileUtil.java b/src/com/android/tradefed/util/FileUtil.java
index 9d919e9..cf15bc2 100644
--- a/src/com/android/tradefed/util/FileUtil.java
+++ b/src/com/android/tradefed/util/FileUtil.java
@@ -564,13 +564,30 @@
* @throws FileNotFoundException
*/
public static String readStringFromFile(File sourceFile) throws IOException {
- FileInputStream is = null;
- try {
- // no need to buffer since StreamUtil does
- is = new FileInputStream(sourceFile);
- return StreamUtil.getStringFromStream(is);
- } finally {
- StreamUtil.close(is);
+ return readStringFromFile(sourceFile, 0, 0);
+ }
+
+ /**
+ * A helper method for reading partial string data from a file
+ *
+ * @param sourceFile the file to read from
+ * @param startOffset the start offset to read from the file.
+ * @param length the number of bytes to read of the file.
+ * @throws IOException
+ * @throws FileNotFoundException
+ */
+ public static String readStringFromFile(File sourceFile, long startOffset, long length)
+ throws IOException {
+ try (FileInputStream is = new FileInputStream(sourceFile)) {
+ if (startOffset < 0) {
+ startOffset = 0;
+ }
+ long fileLength = sourceFile.length();
+ is.skip(startOffset);
+ if (length <= 0 || fileLength <= startOffset + length) {
+ return StreamUtil.getStringFromStream(is);
+ }
+ return StreamUtil.getStringFromStream(is, length);
}
}
diff --git a/src/com/android/tradefed/util/StreamUtil.java b/src/com/android/tradefed/util/StreamUtil.java
index 2f1d009..5cab3b2 100644
--- a/src/com/android/tradefed/util/StreamUtil.java
+++ b/src/com/android/tradefed/util/StreamUtil.java
@@ -111,11 +111,28 @@
* @throws IOException if failure occurred reading the stream
*/
public static String getStringFromStream(InputStream stream) throws IOException {
+ return getStringFromStream(stream, 0);
+ }
+
+ /**
+ * Retrieves a {@link String} from a character stream.
+ *
+ * @param stream the {@link InputStream}
+ * @param length the size of the content to read, set to 0 to read all contents
+ * @return a {@link String} containing the stream contents
+ * @throws IOException if failure occurred reading the stream
+ */
+ public static String getStringFromStream(InputStream stream, long length) throws IOException {
int irChar = -1;
StringBuilder builder = new StringBuilder();
try (Reader ir = new BufferedReader(new InputStreamReader(stream))) {
+ long count = 0;
while ((irChar = ir.read()) != -1) {
builder.append((char) irChar);
+ count++;
+ if (length > 0 && count >= length) {
+ break;
+ }
}
}
return builder.toString();
diff --git a/tests/src/com/android/tradefed/util/FileUtilTest.java b/tests/src/com/android/tradefed/util/FileUtilTest.java
index e0f8ff6..687e783 100644
--- a/tests/src/com/android/tradefed/util/FileUtilTest.java
+++ b/tests/src/com/android/tradefed/util/FileUtilTest.java
@@ -535,4 +535,28 @@
FileUtil.recursiveDelete(tmpDir);
}
}
+
+ @Test
+ public void testReadPartialStringFromFile() throws IOException {
+ File tmpFile = FileUtil.createTempFile("test", ".txt");
+ try {
+ StringBuilder content = new StringBuilder();
+ StringBuilder partialContent = new StringBuilder();
+ for (int i = 0; i < 1024; i++) {
+ content.append('A');
+ }
+ for (int i = 0; i < 1024; i++) {
+ content.append('C');
+ partialContent.append('C');
+ }
+ FileUtil.writeToFile(content.toString(), tmpFile);
+ // Test to read the whole file with `length` greater than the file length.
+ assertEquals(content.toString(), FileUtil.readStringFromFile(tmpFile, -1024, 4096 * 2));
+ // Test to read the tailing part of the file.
+ assertEquals(
+ partialContent.toString(), FileUtil.readStringFromFile(tmpFile, 1024, 4096));
+ } finally {
+ FileUtil.deleteFile(tmpFile);
+ }
+ }
}
diff --git a/tests/src/com/android/tradefed/util/StreamUtilTest.java b/tests/src/com/android/tradefed/util/StreamUtilTest.java
index f1a238c..da1ddd2 100644
--- a/tests/src/com/android/tradefed/util/StreamUtilTest.java
+++ b/tests/src/com/android/tradefed/util/StreamUtilTest.java
@@ -108,8 +108,8 @@
}
/**
- * Verify that {@link com.android.tradefed.util.StreamUtil#getStringFromStream} works as
- * expected.
+ * Verify that {@link com.android.tradefed.util.StreamUtil#getStringFromStream(InputStream)}
+ * works as expected.
*/
public void testGetStringFromStream() throws Exception {
final String contents = "this is a string";
@@ -119,6 +119,17 @@
}
/**
+ * Verify that {@link com.android.tradefed.util.StreamUtil#getStringFromStream(InputStream,
+ * long)} works as expected.
+ */
+ public void testGetStringFromStream_withLength() throws Exception {
+ final String contents = "this is a string";
+ final String output =
+ StreamUtil.getStringFromStream(new ByteArrayInputStream(contents.getBytes()), 5);
+ assertEquals("this ", output);
+ }
+
+ /**
* Verify that {@link com.android.tradefed.util.StreamUtil#calculateMd5(InputStream)} works as
* expected.
*
