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Diffstat (limited to 'taskerlocaleapi/src/main/java/com/twofortyfouram/locale/PackageUtilities.java')
| -rw-r--r-- | taskerlocaleapi/src/main/java/com/twofortyfouram/locale/PackageUtilities.java | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/taskerlocaleapi/src/main/java/com/twofortyfouram/locale/PackageUtilities.java b/taskerlocaleapi/src/main/java/com/twofortyfouram/locale/PackageUtilities.java new file mode 100644 index 00000000..a4b623ce --- /dev/null +++ b/taskerlocaleapi/src/main/java/com/twofortyfouram/locale/PackageUtilities.java @@ -0,0 +1,123 @@ +/* + * Copyright 2013 two forty four a.m. LLC <http://www.twofortyfouram.com> + * + * 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.twofortyfouram.locale; + +import android.content.pm.PackageInfo; +import android.content.pm.PackageManager; + +import java.util.Collections; +import java.util.HashSet; +import java.util.List; +import java.util.Set; + +/** + * A simple utility class to find a package that is compatible with hosting the Locale Developer Platform. + */ +/* + * This class is NOT part of the public Locale Developer Platform API + */ +public final class PackageUtilities +{ + /** + * A hard-coded set of Android packages that support the Locale Developer Platform. + */ + /* + * This is NOT a public field and is subject to change in future releases of the Developer Platform. A + * conscious design decision was made to use hard-coded package names, rather than dynamic discovery of + * packages that might be compatible with hosting the Locale Developer Platform API. This is for two + * reasons: to ensure the host is implemented correctly (hosts must pass the extensive Locale Platform + * Host compatibility test suite) and to prevent malicious applications from crashing plug-ins by + * providing bad values. As additional apps implement the Locale Developer Platform, their package names + * will also be added to this list. + */ + /* + * Note: this is implemented as a Set<String> rather than a String[], in order to enforce immutability. + */ + private static final Set<String> COMPATIBLE_PACKAGES = constructPackageSet(); + + /** + * @return a list wrapped in {@link Collections#unmodifiableList(List)} that represents the set of + * Locale-compatible packages. + */ + private static Set<String> constructPackageSet() + { + final HashSet<String> packages = new HashSet<String>(); + + packages.add(Constants.LOCALE_PACKAGE); + + /* + * Note: Tasker is not 100% compatible with Locale's plug-in API, but it is close enough that these + * packages are enabled. Tasker's known incompatibilities are documented on the Tasker website. + */ + packages.add("net.dinglisch.android.taskerm"); //$NON-NLS-1$ + packages.add("net.dinglisch.android.tasker"); //$NON-NLS-1$ + packages.add("net.dinglisch.android.taskercupcake"); //$NON-NLS-1$ + + return Collections.unmodifiableSet(packages); + } + + /** + * Obtains the {@code String} package name of a currently-installed package which implements the host + * component of the Locale Developer Platform. + * <p> + * Note: A TOCTOU error exists, due to the fact that the package could be uninstalled at any time. + * <p> + * Note: If there are multiple hosts, this method will return one of them. The interface of this method + * makes no guarantee which host will returned, nor whether that host will be consistently returned. + * + * @param manager an instance of {@code PackageManager}. Cannot be null. + * @param packageHint hint as to which package should take precedence. This parameter may be null. + * @return {@code String} package name of a host for the Locale Developer Platform, such as + * "com.twofortyfouram.locale". If no such package is found, returns null. + */ + public static String getCompatiblePackage(final PackageManager manager, final String packageHint) + { + /* + * The interface for this method makes no guarantees as to which host will be returned. However the + * implementation is more predictable. + */ + + final List<PackageInfo> installedPackages = manager.getInstalledPackages(0); + + if (COMPATIBLE_PACKAGES.contains(packageHint)) + { + for (final PackageInfo packageInfo : installedPackages) + { + final String temp = packageInfo.packageName; + if (packageHint.equals(temp)) + { + return temp; + } + } + } + + for (final String compatiblePackageName : COMPATIBLE_PACKAGES) + { + if (compatiblePackageName.equals(packageHint)) + { + continue; + } + + for (final PackageInfo packageInfo : installedPackages) + { + final String temp = packageInfo.packageName; + if (compatiblePackageName.equals(temp)) + { + return temp; + } + } + } + + return null; + } +}
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