Revert "Restore file truncation where expected."

Revert "Restore file truncation where expected."

Revert submission 14173486-rwt

Reason for revert: b/186862362 - breaks ContentResolverWrapTest
Reverted Changes:
I41bc298af:Restore file truncation where expected.
Iacec49164:Restore file truncation where expected.

Bug: 186862362
Change-Id: I2afe5e2334cff60c4e7220267095042a60909185

3 files changed, 44 insertions, 137 deletions

diff --git a/core/java/android/content/ContentProvider.java b/core/java/android/content/ContentProvider.java
index 114ad874d0c4..7e1df1b0e59c 100644
--- a/core/java/android/content/ContentProvider.java
+++ b/core/java/android/content/ContentProvider.java
@@ -1885,9 +1885,9 @@ public abstract class ContentProvider implements ContentInterface, ComponentCall
      * in {@link android.provider.MediaStore.MediaColumns}.</p>
      *
      * @param uri The URI whose file is to be opened.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode Access mode for the file.  May be "r" for read-only access,
+     * "rw" for read and write access, or "rwt" for read and write access
+     * that truncates any existing file.
      *
      * @return Returns a new ParcelFileDescriptor which you can use to access
      * the file.
@@ -1948,9 +1948,10 @@ public abstract class ContentProvider implements ContentInterface, ComponentCall
      * in {@link android.provider.MediaStore.MediaColumns}.</p>
      *
      * @param uri The URI whose file is to be opened.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode Access mode for the file. May be "r" for read-only access,
+     *            "w" for write-only access, "rw" for read and write access, or
+     *            "rwt" for read and write access that truncates any existing
+     *            file.
      * @param signal A signal to cancel the operation in progress, or
      *            {@code null} if none. For example, if you are downloading a
      *            file from the network to service a "rw" mode request, you
@@ -2010,9 +2011,11 @@ public abstract class ContentProvider implements ContentInterface, ComponentCall
      * containing at least the columns specified by {@link android.provider.OpenableColumns}.</p>
      *
      * @param uri The URI whose file is to be opened.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode Access mode for the file.  May be "r" for read-only access,
+     * "w" for write-only access (erasing whatever data is currently in
+     * the file), "wa" for write-only access to append to any existing data,
+     * "rw" for read and write access on any existing data, and "rwt" for read
+     * and write access that truncates any existing file.
      *
      * @return Returns a new AssetFileDescriptor which you can use to access
      * the file.
@@ -2065,9 +2068,11 @@ public abstract class ContentProvider implements ContentInterface, ComponentCall
      * containing at least the columns specified by {@link android.provider.OpenableColumns}.</p>
      *
      * @param uri The URI whose file is to be opened.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode Access mode for the file.  May be "r" for read-only access,
+     * "w" for write-only access (erasing whatever data is currently in
+     * the file), "wa" for write-only access to append to any existing data,
+     * "rw" for read and write access on any existing data, and "rwt" for read
+     * and write access that truncates any existing file.
      * @param signal A signal to cancel the operation in progress, or
      *            {@code null} if none. For example, if you are downloading a
      *            file from the network to service a "rw" mode request, you
@@ -2098,9 +2103,11 @@ public abstract class ContentProvider implements ContentInterface, ComponentCall
      * by looking up a column named "_data" at the given URI.
      *
      * @param uri The URI to be opened.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode The file mode.  May be "r" for read-only access,
+     * "w" for write-only access (erasing whatever data is currently in
+     * the file), "wa" for write-only access to append to any existing data,
+     * "rw" for read and write access on any existing data, and "rwt" for read
+     * and write access that truncates any existing file.
      *
      * @return Returns a new ParcelFileDescriptor that can be used by the
      * client to access the file.
diff --git a/core/java/android/content/ContentResolver.java b/core/java/android/content/ContentResolver.java
index 1132991a57f8..aec39da973f0 100644
--- a/core/java/android/content/ContentResolver.java
+++ b/core/java/android/content/ContentResolver.java
@@ -63,9 +63,7 @@ import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.SystemClock;
 import android.os.UserHandle;
-import android.system.ErrnoException;
 import android.system.Int64Ref;
-import android.system.Os;
 import android.text.TextUtils;
 import android.util.EventLog;
 import android.util.Log;
@@ -78,10 +76,8 @@ import com.android.internal.util.MimeIconUtils;
 import dalvik.system.CloseGuard;
 
 import java.io.File;
-import java.io.FileDescriptor;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -868,20 +864,6 @@ public abstract class ContentResolver implements ContentInterface {
         return wrap((ContentInterface) wrapped);
     }
 
-    /**
-     * Offer to locally truncate the given file when opened using the write-only
-     * mode. This is typically used to preserve legacy compatibility behavior.
-     */
-    private static void maybeTruncate(FileDescriptor fd, String mode) throws FileNotFoundException {
-        if ("w".equals(mode)) {
-            try {
-                Os.ftruncate(fd, 0);
-            } catch (ErrnoException e) {
-                throw new FileNotFoundException("Failed to truncate: " + e.getMessage());
-            }
-        }
-    }
-
     /** @hide */
     @SuppressWarnings("HiddenAbstractMethod")
     @UnsupportedAppUsage
@@ -1543,20 +1525,8 @@ public abstract class ContentResolver implements ContentInterface {
     }
 
     /**
-     * Open a stream on to the content associated with a content URI.  If there
-     * is no data associated with the URI, FileNotFoundException is thrown.
-     *
-     * <h5>Accepts the following URI schemes:</h5>
-     * <ul>
-     * <li>content ({@link #SCHEME_CONTENT})</li>
-     * <li>file ({@link #SCHEME_FILE})</li>
-     * </ul>
-     *
-     * <p>See {@link #openAssetFileDescriptor(Uri, String)} for more information
-     * on these schemes.
-     *
-     * <p>This method behaves like {@link FileOutputStream} and automatically
-     * truncates any existing contents.
+     * Synonym for {@link #openOutputStream(Uri, String)
+     * openOutputStream(uri, "w")}.
      *
      * @param uri The desired URI.
      * @return an OutputStream or {@code null} if the provider recently crashed.
@@ -1564,16 +1534,7 @@ public abstract class ContentResolver implements ContentInterface {
      */
     public final @Nullable OutputStream openOutputStream(@NonNull Uri uri)
             throws FileNotFoundException {
-        AssetFileDescriptor fd = openAssetFileDescriptor(uri, "w", null);
-        if (fd == null) return null;
-        try {
-            final FileOutputStream res = fd.createOutputStream();
-            // Unconditionally truncate to mirror FileOutputStream behavior
-            maybeTruncate(res.getFD(), "w");
-            return res;
-        } catch (IOException e) {
-            throw new FileNotFoundException("Unable to create stream");
-        }
+        return openOutputStream(uri, "w");
     }
 
     /**
@@ -1590,9 +1551,7 @@ public abstract class ContentResolver implements ContentInterface {
      * on these schemes.
      *
      * @param uri The desired URI.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode May be "w", "wa", "rw", or "rwt".
      * @return an OutputStream or {@code null} if the provider recently crashed.
      * @throws FileNotFoundException if the provided URI could not be opened.
      * @see #openAssetFileDescriptor(Uri, String)
@@ -1600,14 +1559,8 @@ public abstract class ContentResolver implements ContentInterface {
     public final @Nullable OutputStream openOutputStream(@NonNull Uri uri, @NonNull String mode)
             throws FileNotFoundException {
         AssetFileDescriptor fd = openAssetFileDescriptor(uri, mode, null);
-        if (fd == null) return null;
         try {
-            final FileOutputStream res = fd.createOutputStream();
-            // Preserve legacy behavior by offering to truncate
-            if (mTargetSdkVersion < Build.VERSION_CODES.Q) {
-                maybeTruncate(res.getFD(), mode);
-            }
-            return res;
+            return fd != null ? fd.createOutputStream() : null;
         } catch (IOException e) {
             throw new FileNotFoundException("Unable to create stream");
         }
@@ -1654,9 +1607,8 @@ public abstract class ContentResolver implements ContentInterface {
      * provider, use {@link ParcelFileDescriptor#closeWithError(String)}.
      *
      * @param uri The desired URI to open.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode The file mode to use, as per {@link ContentProvider#openFile
+     * ContentProvider.openFile}.
      * @return Returns a new ParcelFileDescriptor pointing to the file or {@code null} if the
      * provider recently crashed. You own this descriptor and are responsible for closing it
      * when done.
@@ -1698,9 +1650,8 @@ public abstract class ContentResolver implements ContentInterface {
      * provider, use {@link ParcelFileDescriptor#closeWithError(String)}.
      *
      * @param uri The desired URI to open.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode The file mode to use, as per {@link ContentProvider#openFile
+     * ContentProvider.openFile}.
      * @param cancellationSignal A signal to cancel the operation in progress,
      *         or null if none. If the operation is canceled, then
      *         {@link OperationCanceledException} will be thrown.
@@ -1793,9 +1744,8 @@ public abstract class ContentResolver implements ContentInterface {
      * from any built-in data conversion that a provider implements.
      *
      * @param uri The desired URI to open.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode The file mode to use, as per {@link ContentProvider#openAssetFile
+     * ContentProvider.openAssetFile}.
      * @return Returns a new ParcelFileDescriptor pointing to the file or {@code null} if the
      * provider recently crashed. You own this descriptor and are responsible for closing it
      * when done.
@@ -1848,9 +1798,8 @@ public abstract class ContentResolver implements ContentInterface {
      * from any built-in data conversion that a provider implements.
      *
      * @param uri The desired URI to open.
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt". See
-     *            {@link ParcelFileDescriptor#parseMode} for more details.
+     * @param mode The file mode to use, as per {@link ContentProvider#openAssetFile
+     * ContentProvider.openAssetFile}.
      * @param cancellationSignal A signal to cancel the operation in progress, or null if
      *            none. If the operation is canceled, then
      *            {@link OperationCanceledException} will be thrown.
@@ -1886,10 +1835,6 @@ public abstract class ContentResolver implements ContentInterface {
         } else if (SCHEME_FILE.equals(scheme)) {
             ParcelFileDescriptor pfd = ParcelFileDescriptor.open(
                     new File(uri.getPath()), ParcelFileDescriptor.parseMode(mode));
-            // Preserve legacy behavior by offering to truncate
-            if (mTargetSdkVersion < Build.VERSION_CODES.Q) {
-                maybeTruncate(pfd.getFileDescriptor(), mode);
-            }
             return new AssetFileDescriptor(pfd, 0, -1);
         } else {
             if ("r".equals(mode)) {
@@ -1947,11 +1892,6 @@ public abstract class ContentResolver implements ContentInterface {
                     // ParcelFileDescriptorInner do that when it is closed.
                     stableProvider = null;
 
-                    // Preserve legacy behavior by offering to truncate
-                    if (mTargetSdkVersion < Build.VERSION_CODES.Q) {
-                        maybeTruncate(pfd.getFileDescriptor(), mode);
-                    }
-
                     return new AssetFileDescriptor(pfd, fd.getStartOffset(),
                             fd.getDeclaredLength());
 
diff --git a/core/java/android/os/ParcelFileDescriptor.java b/core/java/android/os/ParcelFileDescriptor.java
index 0c9ad1b17a7e..c0847872a45a 100644
--- a/core/java/android/os/ParcelFileDescriptor.java
+++ b/core/java/android/os/ParcelFileDescriptor.java
@@ -31,7 +31,6 @@ import static android.system.OsConstants.S_ISLNK;
 import static android.system.OsConstants.S_ISREG;
 import static android.system.OsConstants.S_IWOTH;
 
-import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.SuppressLint;
 import android.annotation.SystemApi;
@@ -64,8 +63,6 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InterruptedIOException;
 import java.io.UncheckedIOException;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
 import java.net.DatagramSocket;
 import java.net.Socket;
 import java.nio.ByteOrder;
@@ -113,20 +110,6 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
 
     private final CloseGuard mGuard = CloseGuard.get();
 
-    /** @hide */
-    @IntDef(prefix = {"MODE_"}, value = {
-            MODE_WORLD_READABLE,
-            MODE_WORLD_WRITEABLE,
-            MODE_READ_ONLY,
-            MODE_WRITE_ONLY,
-            MODE_READ_WRITE,
-            MODE_CREATE,
-            MODE_TRUNCATE,
-            MODE_APPEND,
-    })
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface Mode { }
-
     /**
      * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied and
      * this file doesn't already exist, then create the file with permissions
@@ -244,8 +227,7 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
      *             be opened with the requested mode.
      * @see #parseMode(String)
      */
-    public static ParcelFileDescriptor open(File file, @Mode int mode)
-            throws FileNotFoundException {
+    public static ParcelFileDescriptor open(File file, int mode) throws FileNotFoundException {
         final FileDescriptor fd = openInternal(file, mode);
         if (fd == null) return null;
 
@@ -277,7 +259,7 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
     // We can't accept a generic Executor here, since we need to use
     // MessageQueue.addOnFileDescriptorEventListener()
     @SuppressLint("ExecutorRegistration")
-    public static ParcelFileDescriptor open(File file, @Mode int mode, Handler handler,
+    public static ParcelFileDescriptor open(File file, int mode, Handler handler,
             final OnCloseListener listener) throws IOException {
         if (handler == null) {
             throw new IllegalArgumentException("Handler must not be null");
@@ -348,8 +330,7 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
         return pfd;
     }
 
-    private static FileDescriptor openInternal(File file, @Mode int mode)
-            throws FileNotFoundException {
+    private static FileDescriptor openInternal(File file, int mode) throws FileNotFoundException {
         final int flags = FileUtils.translateModePfdToPosix(mode) | ifAtLeastQ(O_CLOEXEC);
 
         int realMode = S_IRWXU | S_IRWXG;
@@ -642,36 +623,15 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
     }
 
     /**
-     * Converts a string representing a file mode, such as "rw", into a bitmask
-     * suitable for use with {@link #open}.
+     * Converts a string representing a file mode, such as "rw", into a bitmask suitable for use
+     * with {@link #open}.
      * <p>
-     * The argument must define at least one of the following base access modes:
-     * <ul>
-     * <li>"r" indicates the file should be opened in read-only mode, equivalent
-     * to {@link OsConstants#O_RDONLY}.
-     * <li>"w" indicates the file should be opened in write-only mode,
-     * equivalent to {@link OsConstants#O_WRONLY}.
-     * <li>"rw" indicates the file should be opened in read-write mode,
-     * equivalent to {@link OsConstants#O_RDWR}.
-     * </ul>
-     * In addition to a base access mode, the following additional modes may
-     * requested:
-     * <ul>
-     * <li>"a" indicates the file should be opened in append mode, equivalent to
-     * {@link OsConstants#O_APPEND}. Before each write, the file offset is
-     * positioned at the end of the file.
-     * <li>"t" indicates the file should be opened in truncate mode, equivalent
-     * to {@link OsConstants#O_TRUNC}. If the file already exists and is a
-     * regular file and is opened for writing, it will be truncated to length 0.
-     * </ul>
-     *
-     * @param mode The string representation of the file mode. Can be "r", "w",
-     *            "wt", "wa", "rw" or "rwt".
+     * @param mode The string representation of the file mode. Can be "r", "w", "wt", "wa", "rw"
+     *             or "rwt".
      * @return A bitmask representing the given file mode.
-     * @throws IllegalArgumentException if the given string does not match a
-     *             known file mode.
+     * @throws IllegalArgumentException if the given string does not match a known file mode.
      */
-    public static @Mode int parseMode(String mode) {
+    public static int parseMode(String mode) {
         return FileUtils.translateModePosixToPfd(FileUtils.translateModeStringToPosix(mode));
     }