de.robv.android.xposed.services.BaseService Maven / Gradle / Ivy
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package de.robv.android.xposed.services;
import java.io.ByteArrayInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
/**
* General definition of a file access service provided by the Xposed framework.
*
* References to a concrete subclass should generally be retrieved from {@link SELinuxHelper}.
*/
public abstract class BaseService {
/** Flag for {@link #checkFileAccess}: Read access. */
public static final int R_OK = 4;
/** Flag for {@link #checkFileAccess}: Write access. */
public static final int W_OK = 2;
/** Flag for {@link #checkFileAccess}: Executable access. */
public static final int X_OK = 1;
/** Flag for {@link #checkFileAccess}: File/directory exists. */
public static final int F_OK = 0;
/**
* Checks whether the services accesses files directly (instead of using IPC).
*
* @return {@code true} in case direct access is possible.
*/
public boolean hasDirectFileAccess() {
return false;
}
/**
* Check whether a file is accessible. SELinux might enforce stricter checks.
*
* @param filename The absolute path of the file to check.
* @param mode The mode for POSIX's {@code access()} function.
* @return The result of the {@code access()} function.
*/
public abstract boolean checkFileAccess(String filename, int mode);
/**
* Check whether a file exists.
*
* @param filename The absolute path of the file to check.
* @return The result of the {@code access()} function.
*/
@SuppressWarnings("BooleanMethodIsAlwaysInverted")
public boolean checkFileExists(String filename) {
return checkFileAccess(filename, F_OK);
}
/**
* Determine the size and modification time of a file.
*
* @param filename The absolute path of the file to check.
* @return A {@link FileResult} object holding the result.
* @throws IOException In case an error occurred while retrieving the information.
*/
public abstract FileResult statFile(String filename) throws IOException;
/**
* Determine the size time of a file.
*
* @param filename The absolute path of the file to check.
* @return The file size.
* @throws IOException In case an error occurred while retrieving the information.
*/
public long getFileSize(String filename) throws IOException {
return statFile(filename).size;
}
/**
* Determine the size time of a file.
*
* @param filename The absolute path of the file to check.
* @return The file modification time.
* @throws IOException In case an error occurred while retrieving the information.
*/
public long getFileModificationTime(String filename) throws IOException {
return statFile(filename).mtime;
}
/**
* Read a file into memory.
*
* @param filename The absolute path of the file to read.
* @return A {@code byte} array with the file content.
* @throws IOException In case an error occurred while reading the file.
*/
public abstract byte[] readFile(String filename) throws IOException;
/**
* Read a file into memory, but only if it has changed since the last time.
*
* @param filename The absolute path of the file to read.
* @param previousSize File size of last read.
* @param previousTime File modification time of last read.
* @return A {@link FileResult} object holding the result.
*
The {@link FileResult#content} field might be {@code null} if the file
* is unmodified ({@code previousSize} and {@code previousTime} are still valid).
* @throws IOException In case an error occurred while reading the file.
*/
public abstract FileResult readFile(String filename, long previousSize, long previousTime) throws IOException;
/**
* Read a file into memory, optionally only if it has changed since the last time.
*
* @param filename The absolute path of the file to read.
* @param offset Number of bytes to skip at the beginning of the file.
* @param length Number of bytes to read (0 means read to end of file).
* @param previousSize Optional: File size of last read.
* @param previousTime Optional: File modification time of last read.
* @return A {@link FileResult} object holding the result.
*
The {@link FileResult#content} field might be {@code null} if the file
* is unmodified ({@code previousSize} and {@code previousTime} are still valid).
* @throws IOException In case an error occurred while reading the file.
*/
public abstract FileResult readFile(String filename, int offset, int length,
long previousSize, long previousTime) throws IOException;
/**
* Get a stream to the file content.
* Depending on the service, it may or may not be read completely into memory.
*
* @param filename The absolute path of the file to read.
* @return An {@link InputStream} to the file content.
* @throws IOException In case an error occurred while reading the file.
*/
public InputStream getFileInputStream(String filename) throws IOException {
return new ByteArrayInputStream(readFile(filename));
}
/**
* Get a stream to the file content, but only if it has changed since the last time.
* Depending on the service, it may or may not be read completely into memory.
*
* @param filename The absolute path of the file to read.
* @param previousSize Optional: File size of last read.
* @param previousTime Optional: File modification time of last read.
* @return A {@link FileResult} object holding the result.
*
The {@link FileResult#stream} field might be {@code null} if the file
* is unmodified ({@code previousSize} and {@code previousTime} are still valid).
* @throws IOException In case an error occurred while reading the file.
*/
public FileResult getFileInputStream(String filename, long previousSize, long previousTime) throws IOException {
FileResult result = readFile(filename, previousSize, previousTime);
if (result.content == null)
return result;
return new FileResult(new ByteArrayInputStream(result.content), result.size, result.mtime);
}
// ----------------------------------------------------------------------------
/*package*/ BaseService() {}
/*package*/ static void ensureAbsolutePath(String filename) {
if (!filename.startsWith("/")) {
throw new IllegalArgumentException("Only absolute filenames are allowed: " + filename);
}
}
/*package*/ static void throwCommonIOException(int errno, String errorMsg, String filename, String defaultText) throws IOException {
switch (errno) {
case 1: // EPERM
case 13: // EACCES
throw new FileNotFoundException(errorMsg != null ? errorMsg : "Permission denied: " + filename);
case 2: // ENOENT
throw new FileNotFoundException(errorMsg != null ? errorMsg : "No such file or directory: " + filename);
case 12: // ENOMEM
throw new OutOfMemoryError(errorMsg);
case 21: // EISDIR
throw new FileNotFoundException(errorMsg != null ? errorMsg : "Is a directory: " + filename);
default:
throw new IOException(errorMsg != null ? errorMsg : "Error " + errno + defaultText + filename);
}
}
}