src/com/android/documentsui/base/DocumentStack.java - platform/packages/apps/DocumentsUI - Gitiles

 /*
  * Copyright (C) 2013 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.android.documentsui.base;

 import static com.android.documentsui.base.Shared.DEBUG;

 import android.content.ContentResolver;
 import android.database.Cursor;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.provider.DocumentsProvider;
 import android.util.Log;

 import com.android.documentsui.picker.LastAccessedProvider;

 import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.net.ProtocolException;
 import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Objects;

 import javax.annotation.Nullable;

 /**
  * Representation of a stack of {@link DocumentInfo}, usually the result of a
  * user-driven traversal.
  */
 public class DocumentStack implements Durable, Parcelable {

     private static final String TAG = "DocumentStack";

     private static final int VERSION_INIT = 1;
     private static final int VERSION_ADD_ROOT = 2;

     private LinkedList<DocumentInfo> mList;
     private @Nullable RootInfo mRoot;

     private boolean mStackTouched;

     public DocumentStack() {
         mList = new LinkedList<>();
     }

     /**
      * Creates an instance, and pushes all docs to it in the same order as they're passed as
      * parameters, i.e. the last document will be at the top of the stack.
      */
     public DocumentStack(RootInfo root, DocumentInfo... docs) {
         mList = new LinkedList<>();
         for (int i = 0; i < docs.length; ++i) {
             mList.add(docs[i]);
         }

         mRoot = root;
     }

     /**
      * Same as {@link #DocumentStack(DocumentStack, DocumentInfo...)} except it takes a {@link List}
      * instead of an array.
      */
     public DocumentStack(RootInfo root, List<DocumentInfo> docs) {
         mList = new LinkedList<>(docs);
         mRoot = root;
     }

     /**
      * Makes a new copy, and pushes all docs to the new copy in the same order as they're
      * passed as parameters, i.e. the last document will be at the top of the stack.
      */
     public DocumentStack(DocumentStack src, DocumentInfo... docs) {
         mList = new LinkedList<>(src.mList);
         for (DocumentInfo doc : docs) {
             push(doc);
         }

         mStackTouched = false;
         mRoot = src.mRoot;
     }

     public boolean isInitialized() {
         return mRoot != null;
     }

     public @Nullable RootInfo getRoot() {
         return mRoot;
     }

     public boolean isEmpty() {
         return mList.isEmpty();
     }

     public int size() {
         return mList.size();
     }

     public DocumentInfo peek() {
         return mList.peekLast();
     }

     /**
      * Returns {@link DocumentInfo} at index counted from the bottom of this stack.
      */
     public DocumentInfo get(int index) {
         return mList.get(index);
     }

     public void push(DocumentInfo info) {
         boolean alreadyInStack = mList.contains(info);
         assert (!alreadyInStack);
         if (!alreadyInStack) {
             if (DEBUG) Log.d(TAG, "Adding doc to stack: " + info);
             mList.addLast(info);
             mStackTouched = true;
         }
     }

     public DocumentInfo pop() {
         if (DEBUG) Log.d(TAG, "Popping doc off stack.");
         final DocumentInfo result = mList.removeLast();
         mStackTouched = true;

         return result;
     }

     public void popToRootDocument() {
         if (DEBUG) Log.d(TAG, "Popping docs to root folder.");
         while (mList.size() > 1) {
             mList.removeLast();
         }
         mStackTouched = true;
     }

     public void changeRoot(RootInfo root) {
         if (DEBUG) Log.d(TAG, "Root changed to: " + root);
         reset();
         mRoot = root;
     }

     /** This will return true even when the initial location is set.
      * To get a read on if the user has changed something, use {@link #hasInitialLocationChanged()}.
      */
     public boolean hasLocationChanged() {
         return mStackTouched;
     }

     public String getTitle() {
         if (mList.size() == 1 && mRoot != null) {
             return mRoot.title;
         } else if (mList.size() > 1) {
             return peek().displayName;
         } else {
             return null;
         }
     }

     public boolean isRecents() {
         return mRoot != null && mRoot.isRecents();
     }

     /**
      * Resets this stack to the given stack. It takes the reference of {@link #mList} and
      * {@link #mRoot} instead of making a copy.
      */
     public void reset(DocumentStack stack) {
         if (DEBUG) Log.d(TAG, "Resetting the whole darn stack to: " + stack);

         mList = stack.mList;
         mRoot = stack.mRoot;
         mStackTouched = true;
     }

     @Override
     public String toString() {
         return "DocumentStack{"
                 + "root=" + mRoot
                 + ", docStack=" + mList
                 + ", stackTouched=" + mStackTouched
                 + "}";
     }

     @Override
     public void reset() {
         mList.clear();
         mRoot = null;
     }

     private void updateRoot(Collection<RootInfo> matchingRoots) throws FileNotFoundException {
         for (RootInfo root : matchingRoots) {
             // RootInfo's equals() only checks authority and rootId, so this will update RootInfo if
             // its flag has changed.
             if (root.equals(this.mRoot)) {
                 this.mRoot = root;
                 return;
             }
         }
         throw new FileNotFoundException("Failed to find matching mRoot for " + mRoot);
     }

     /**
      * Update a possibly stale restored stack against a live
      * {@link DocumentsProvider}.
      */
     private void updateDocuments(ContentResolver resolver) throws FileNotFoundException {
         for (DocumentInfo info : mList) {
             info.updateSelf(resolver);
         }
     }

     public static @Nullable DocumentStack fromLastAccessedCursor(
             Cursor cursor, Collection<RootInfo> matchingRoots, ContentResolver resolver)
             throws IOException {

         if (cursor.moveToFirst()) {
             DocumentStack stack = new DocumentStack();
             final byte[] rawStack = cursor.getBlob(
                     cursor.getColumnIndex(LastAccessedProvider.Columns.STACK));
             DurableUtils.readFromArray(rawStack, stack);

             stack.updateRoot(matchingRoots);
             stack.updateDocuments(resolver);

             return stack;
         }

         return null;
     }

     @Override
     public boolean equals(Object o) {
         if (this == o) {
             return true;
         }

         if (!(o instanceof DocumentStack)) {
             return false;
         }

         DocumentStack other = (DocumentStack) o;
         return Objects.equals(mRoot, other.mRoot)
                 && mList.equals(other.mList);
     }

     @Override
     public int hashCode() {
         return Objects.hash(mRoot, mList);
     }

     @Override
     public void read(DataInputStream in) throws IOException {
         final int version = in.readInt();
         switch (version) {
             case VERSION_INIT:
                 throw new ProtocolException("Ignored upgrade");
             case VERSION_ADD_ROOT:
                 if (in.readBoolean()) {
                     mRoot = new RootInfo();
                     mRoot.read(in);
                 }
                 final int size = in.readInt();
                 for (int i = 0; i < size; i++) {
                     final DocumentInfo doc = new DocumentInfo();
                     doc.read(in);
                     mList.add(doc);
                 }
                 mStackTouched = in.readInt() != 0;
                 break;
             default:
                 throw new ProtocolException("Unknown version " + version);
         }
     }

     @Override
     public void write(DataOutputStream out) throws IOException {
         out.writeInt(VERSION_ADD_ROOT);
         if (mRoot != null) {
             out.writeBoolean(true);
             mRoot.write(out);
         } else {
             out.writeBoolean(false);
         }
         final int size = mList.size();
         out.writeInt(size);
         for (int i = 0; i < size; i++) {
             final DocumentInfo doc = mList.get(i);
             doc.write(out);
         }
         out.writeInt(mStackTouched ? 1 : 0);
     }

     @Override
     public int describeContents() {
         return 0;
     }

     @Override
     public void writeToParcel(Parcel dest, int flags) {
         DurableUtils.writeToParcel(dest, this);
     }

     public static final Creator<DocumentStack> CREATOR = new Creator<DocumentStack>() {
         @Override
         public DocumentStack createFromParcel(Parcel in) {
             final DocumentStack stack = new DocumentStack();
             DurableUtils.readFromParcel(in, stack);
             return stack;
         }

         @Override
         public DocumentStack[] newArray(int size) {
             return new DocumentStack[size];
         }
     };
 }
	/*
	* Copyright (C) 2013 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.android.documentsui.base;

	import static com.android.documentsui.base.Shared.DEBUG;

	import android.content.ContentResolver;
	import android.database.Cursor;
	import android.os.Parcel;
	import android.os.Parcelable;
	import android.provider.DocumentsProvider;
	import android.util.Log;

	import com.android.documentsui.picker.LastAccessedProvider;

	import java.io.DataInputStream;
	import java.io.DataOutputStream;
	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.net.ProtocolException;
	import java.util.Collection;
	import java.util.LinkedList;
	import java.util.List;
	import java.util.Objects;

	import javax.annotation.Nullable;

	/**
	* Representation of a stack of {@link DocumentInfo}, usually the result of a
	* user-driven traversal.
	*/
	public class DocumentStack implements Durable, Parcelable {

	private static final String TAG = "DocumentStack";

	private static final int VERSION_INIT = 1;
	private static final int VERSION_ADD_ROOT = 2;

	private LinkedList<DocumentInfo> mList;
	private @Nullable RootInfo mRoot;

	private boolean mStackTouched;

	public DocumentStack() {
	mList = new LinkedList<>();
	}

	/**
	* Creates an instance, and pushes all docs to it in the same order as they're passed as
	* parameters, i.e. the last document will be at the top of the stack.
	*/
	public DocumentStack(RootInfo root, DocumentInfo... docs) {
	mList = new LinkedList<>();
	for (int i = 0; i < docs.length; ++i) {
	mList.add(docs[i]);
	}

	mRoot = root;
	}

	/**
	* Same as {@link #DocumentStack(DocumentStack, DocumentInfo...)} except it takes a {@link List}
	* instead of an array.
	*/
	public DocumentStack(RootInfo root, List<DocumentInfo> docs) {
	mList = new LinkedList<>(docs);
	mRoot = root;
	}

	/**
	* Makes a new copy, and pushes all docs to the new copy in the same order as they're
	* passed as parameters, i.e. the last document will be at the top of the stack.
	*/
	public DocumentStack(DocumentStack src, DocumentInfo... docs) {
	mList = new LinkedList<>(src.mList);
	for (DocumentInfo doc : docs) {
	push(doc);
	}

	mStackTouched = false;
	mRoot = src.mRoot;
	}

	public boolean isInitialized() {
	return mRoot != null;
	}

	public @Nullable RootInfo getRoot() {
	return mRoot;
	}

	public boolean isEmpty() {
	return mList.isEmpty();
	}

	public int size() {
	return mList.size();
	}

	public DocumentInfo peek() {
	return mList.peekLast();
	}

	/**
	* Returns {@link DocumentInfo} at index counted from the bottom of this stack.
	*/
	public DocumentInfo get(int index) {
	return mList.get(index);
	}

	public void push(DocumentInfo info) {
	boolean alreadyInStack = mList.contains(info);
	assert (!alreadyInStack);
	if (!alreadyInStack) {
	if (DEBUG) Log.d(TAG, "Adding doc to stack: " + info);
	mList.addLast(info);
	mStackTouched = true;
	}
	}

	public DocumentInfo pop() {
	if (DEBUG) Log.d(TAG, "Popping doc off stack.");
	final DocumentInfo result = mList.removeLast();
	mStackTouched = true;

	return result;
	}

	public void popToRootDocument() {
	if (DEBUG) Log.d(TAG, "Popping docs to root folder.");
	while (mList.size() > 1) {
	mList.removeLast();
	}
	mStackTouched = true;
	}

	public void changeRoot(RootInfo root) {
	if (DEBUG) Log.d(TAG, "Root changed to: " + root);
	reset();
	mRoot = root;
	}

	/** This will return true even when the initial location is set.
	* To get a read on if the user has changed something, use {@link #hasInitialLocationChanged()}.
	*/
	public boolean hasLocationChanged() {
	return mStackTouched;
	}

	public String getTitle() {
	if (mList.size() == 1 && mRoot != null) {
	return mRoot.title;
	} else if (mList.size() > 1) {
	return peek().displayName;
	} else {
	return null;
	}
	}

	public boolean isRecents() {
	return mRoot != null && mRoot.isRecents();
	}

	/**
	* Resets this stack to the given stack. It takes the reference of {@link #mList} and
	* {@link #mRoot} instead of making a copy.
	*/
	public void reset(DocumentStack stack) {
	if (DEBUG) Log.d(TAG, "Resetting the whole darn stack to: " + stack);

	mList = stack.mList;
	mRoot = stack.mRoot;
	mStackTouched = true;
	}

	@Override
	public String toString() {
	return "DocumentStack{"
	+ "root=" + mRoot
	+ ", docStack=" + mList
	+ ", stackTouched=" + mStackTouched
	+ "}";
	}

	@Override
	public void reset() {
	mList.clear();
	mRoot = null;
	}

	private void updateRoot(Collection<RootInfo> matchingRoots) throws FileNotFoundException {
	for (RootInfo root : matchingRoots) {
	// RootInfo's equals() only checks authority and rootId, so this will update RootInfo if
	// its flag has changed.
	if (root.equals(this.mRoot)) {
	this.mRoot = root;
	return;
	}
	}
	throw new FileNotFoundException("Failed to find matching mRoot for " + mRoot);
	}

	/**
	* Update a possibly stale restored stack against a live
	* {@link DocumentsProvider}.
	*/
	private void updateDocuments(ContentResolver resolver) throws FileNotFoundException {
	for (DocumentInfo info : mList) {
	info.updateSelf(resolver);
	}
	}

	public static @Nullable DocumentStack fromLastAccessedCursor(
	Cursor cursor, Collection<RootInfo> matchingRoots, ContentResolver resolver)
	throws IOException {

	if (cursor.moveToFirst()) {
	DocumentStack stack = new DocumentStack();
	final byte[] rawStack = cursor.getBlob(
	cursor.getColumnIndex(LastAccessedProvider.Columns.STACK));
	DurableUtils.readFromArray(rawStack, stack);

	stack.updateRoot(matchingRoots);
	stack.updateDocuments(resolver);

	return stack;
	}

	return null;
	}

	@Override
	public boolean equals(Object o) {
	if (this == o) {
	return true;
	}

	if (!(o instanceof DocumentStack)) {
	return false;
	}

	DocumentStack other = (DocumentStack) o;
	return Objects.equals(mRoot, other.mRoot)
	&& mList.equals(other.mList);
	}

	@Override
	public int hashCode() {
	return Objects.hash(mRoot, mList);
	}

	@Override
	public void read(DataInputStream in) throws IOException {
	final int version = in.readInt();
	switch (version) {
	case VERSION_INIT:
	throw new ProtocolException("Ignored upgrade");
	case VERSION_ADD_ROOT:
	if (in.readBoolean()) {
	mRoot = new RootInfo();
	mRoot.read(in);
	}
	final int size = in.readInt();
	for (int i = 0; i < size; i++) {
	final DocumentInfo doc = new DocumentInfo();
	doc.read(in);
	mList.add(doc);
	}
	mStackTouched = in.readInt() != 0;
	break;
	default:
	throw new ProtocolException("Unknown version " + version);
	}
	}

	@Override
	public void write(DataOutputStream out) throws IOException {
	out.writeInt(VERSION_ADD_ROOT);
	if (mRoot != null) {
	out.writeBoolean(true);
	mRoot.write(out);
	} else {
	out.writeBoolean(false);
	}
	final int size = mList.size();
	out.writeInt(size);
	for (int i = 0; i < size; i++) {
	final DocumentInfo doc = mList.get(i);
	doc.write(out);
	}
	out.writeInt(mStackTouched ? 1 : 0);
	}

	@Override
	public int describeContents() {
	return 0;
	}

	@Override
	public void writeToParcel(Parcel dest, int flags) {
	DurableUtils.writeToParcel(dest, this);
	}

	public static final Creator<DocumentStack> CREATOR = new Creator<DocumentStack>() {
	@Override
	public DocumentStack createFromParcel(Parcel in) {
	final DocumentStack stack = new DocumentStack();
	DurableUtils.readFromParcel(in, stack);
	return stack;
	}

	@Override
	public DocumentStack[] newArray(int size) {
	return new DocumentStack[size];
	}
	};
	}