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/*
* Copyright 2021 eddiemuc
*
* This program is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along with
* this program. If not, see
* Implementation note: these methods do not use DocumentFile internally,
* but query directly for document info due to vastly better performance.
* Also for better performance, this implementation caches resource uris.
*
* Note: this implementation requires minimum Android 5.0 (API 21)
*/
public class ContentResolverResourceProvider implements XmlThemeResourceProvider {
private final ContentResolver contentResolver;
private final Uri relativeRootUri;
private final boolean isDocumentUri;
private final Map resourceUriCache = new HashMap<>();
private static class DocumentInfo {
private final String name;
private final Uri uri;
private final boolean isDirectory;
private DocumentInfo(String name, Uri uri, boolean isDirectory) {
this.name = name;
this.uri = uri;
this.isDirectory = isDirectory;
}
}
/**
* Creates a new content resolver resource provider.
*
* @param contentResolver content resolver used to read content.
* @param relativeRootUri uri pointing to a directory.
* Uri is assumed to be a pure tree Uri (as e.g. returned by {@link Intent#ACTION_OPEN_DOCUMENT_TREE}).
*/
public ContentResolverResourceProvider(ContentResolver contentResolver, Uri relativeRootUri) {
this(contentResolver, relativeRootUri, false);
}
/**
* Creates a new content resolver resource provider.
*
* @param contentResolver content resolver used to read content.
* @param relativeRootUri uri pointing to a directory.
* @param isDocumentUri Uris as returned e.g. by {@link Intent#ACTION_OPEN_DOCUMENT_TREE}) cannot directly be used to scan directories and read content.
* They must be converted to document uris first using {@link DocumentsContract#buildChildDocumentsUriUsingTree(Uri, String)}.
* However, in some situations this conversion was done previously by caller (e.g. if root dir should be subdirectory of a directory returned by {@link Intent#ACTION_OPEN_DOCUMENT_TREE}).
* In these cases, converted Uri will point to original root directory which is not always the wanted behaviour.
* Thus, this parameter allows caller to control whether conversion should be done or not.
* If set to true, then given Uri is considered to be a document uri already and no conversion is done.
* If set to false, uri is considered to be a pure tree uri as returned e.g. by {@link Intent#ACTION_OPEN_DOCUMENT_TREE}) and it is converted.
*/
public ContentResolverResourceProvider(ContentResolver contentResolver, Uri relativeRootUri, boolean isDocumentUri) {
this.contentResolver = contentResolver;
this.relativeRootUri = relativeRootUri;
this.isDocumentUri = isDocumentUri;
refreshCache();
}
/**
* Build uri cache for one dir level (recursive function).
*/
private void buildCacheLevel(String prefix, Uri dirUri) {
List docs = queryDir(dirUri);
for (DocumentInfo doc : docs) {
if (doc.isDirectory) {
buildCacheLevel(prefix + doc.name + "/", doc.uri);
} else {
// Store both relative urls and absolute urls
resourceUriCache.put(CanvasAdapter.PREFIX_FILE + prefix + doc.name, doc.uri);
resourceUriCache.put(CanvasAdapter.PREFIX_FILE + "/" + prefix + doc.name, doc.uri);
}
}
}
@Override
public InputStream createInputStream(String relativePath, String source) throws FileNotFoundException {
Uri docUri = resourceUriCache.get(source);
if (docUri != null) {
return contentResolver.openInputStream(docUri);
}
return null;
}
/**
* Query the content of a directory using scoped storage.
*
* @return a list of arrays with info [0: name (String), 1: uri (Uri), 2: isDir (boolean)]
*/
private List queryDir(Uri dirUri) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
return Collections.emptyList();
}
if (dirUri == null) {
return Collections.emptyList();
}
List result = new ArrayList<>();
Uri childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(dirUri, DocumentsContract.getDocumentId(dirUri));
String[] columns = new String[]{
DocumentsContract.Document.COLUMN_DOCUMENT_ID,
DocumentsContract.Document.COLUMN_DISPLAY_NAME,
DocumentsContract.Document.COLUMN_MIME_TYPE
};
Cursor c = null;
try {
c = contentResolver.query(childrenUri, columns, null, null, null);
while (c.moveToNext()) {
String documentId = c.getString(0);
String name = c.getString(1);
String mimeType = c.getString(2);
Uri uri = DocumentsContract.buildDocumentUriUsingTree(dirUri, documentId);
boolean isDir = DocumentsContract.Document.MIME_TYPE_DIR.equals(mimeType);
result.add(new DocumentInfo(name, uri, isDir));
}
return result;
} finally {
IOUtils.closeQuietly(c);
}
}
/**
* Refresh the uri cache by recreating it.
*/
private void refreshCache() {
resourceUriCache.clear();
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
return;
}
if (relativeRootUri == null) {
return;
}
Uri dirUri = relativeRootUri;
if (!isDocumentUri) {
// Convert "tree uri" to a "document uri"
dirUri = DocumentsContract.buildDocumentUriUsingTree(dirUri, DocumentsContract.getTreeDocumentId(dirUri));
}
buildCacheLevel("", dirUri);
}
}