Save encrypted logs to disk on debug builds.

bramble-api/src/main/java/org/briarproject/bramble/api/FeatureFlags.java

@@ -10,4 +10,6 @@ public interface FeatureFlags {
 	boolean shouldEnableProfilePictures();
 
 	boolean shouldEnableDisappearingMessages();
+
+	boolean shouldEnablePersistentLogs();
 }

bramble-api/src/main/java/org/briarproject/bramble/api/StringMap.java

@@ -1,8 +1,16 @@
 package org.briarproject.bramble.api;
 
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
 import java.util.Hashtable;
 import java.util.Map;
 
+import javax.annotation.Nullable;
+
+import static org.briarproject.bramble.util.StringUtils.fromHexString;
+import static org.briarproject.bramble.util.StringUtils.toHexString;
+
+@NotNullByDefault
 public abstract class StringMap extends Hashtable<String, String> {
 
 	protected StringMap(Map<String, String> m) {
@@ -52,4 +60,19 @@ public abstract class StringMap extends Hashtable<String, String> {
 	public void putLong(String key, long value) {
 		put(key, String.valueOf(value));
 	}
+
+	@Nullable
+	public byte[] getBytes(String key) {
+		String s = get(key);
+		if (s == null) return null;
+		try {
+			return fromHexString(s);
+		} catch (IllegalArgumentException e) {
+			return null;
+		}
+	}
+
+	public void putBytes(String key, byte[] value) {
+		put(key, toHexString(value));
+	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/logging/PersistentLogManager.java

@@ -0,0 +1,46 @@
+package org.briarproject.bramble.api.logging;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.settings.Settings;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Scanner;
+import java.util.logging.Handler;
+import java.util.logging.Logger;
+
+@NotNullByDefault
+public interface PersistentLogManager {
+
+	/**
+	 * The namespace of the (@link Settings) where the log key is stored.
+	 */
+	String LOG_SETTINGS_NAMESPACE = "log";
+
+	/**
+	 * The {@link Settings} key under which the log key is stored.
+	 */
+	String LOG_KEY_KEY = "logKey";
+
+	/**
+	 * Creates and returns a persistent log handler that stores its logs in
+	 * the given directory.
+	 */
+	Handler createLogHandler(File dir) throws IOException;
+
+	/**
+	 * Creates a persistent log handler that stores its logs in the given
+	 * directory and adds the handler to the given logger, replacing any
+	 * existing persistent log handler.
+	 */
+	void addLogHandler(File dir, Logger logger) throws IOException;
+
+	/**
+	 * Returns a {@link Scanner} for reading the persistent log entries stored
+	 * in the given directory.
+	 *
+	 * @param old True if the previous session's log should be loaded, or false
+	 * if the current session's log should be loaded
+	 */
+	Scanner getPersistentLog(File dir, boolean old) throws IOException;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/reporting/DevConfig.java

@@ -8,11 +8,24 @@ import java.io.File;
 @NotNullByDefault
 public interface DevConfig {
 
+	/**
+	 * Returns the public key for encrypting feedback and crash reports.
+	 */
 	PublicKey getDevPublicKey();
 
+	/**
+	 * Returns the onion address for submitting feedback and crash reports.
+	 */
 	String getDevOnionAddress();
 
+	/**
+	 * Returns the directory for storing unsent feedback and crash reports.
+	 */
 	File getReportDir();
 
-	File getLogcatFile();
+	/**
+	 * Returns the temporary file for passing the encrypted app log from the
+	 * main process to the crash reporter process.
+	 */
+	File getTemporaryLogFile();
 }

bramble-api/src/main/java/org/briarproject/bramble/util/LogUtils.java

@@ -1,7 +1,10 @@
 package org.briarproject.bramble.util;
 
 import java.io.File;
+import java.util.Collection;
+import java.util.logging.Formatter;
 import java.util.logging.Level;
+import java.util.logging.LogRecord;
 import java.util.logging.Logger;
 
 import static java.util.logging.Level.FINE;
@@ -57,4 +60,13 @@ public class LogUtils {
 			String type) {
 		logger.log(level, type + " " + f.getAbsolutePath() + " " + f.length());
 	}
+
+	public static String formatLog(Formatter formatter,
+			Collection<LogRecord> logRecords) {
+		StringBuilder sb = new StringBuilder();
+		for (LogRecord record : logRecords) {
+			sb.append(formatter.format(record)).append('\n');
+		}
+		return sb.toString();
+	}
 }