From 7dde3314546315a7f1de793720c47256ba921c40 Mon Sep 17 00:00:00 2001
From: Felix Ableitner <me@nutomic.com>
Date: Fri, 16 Dec 2016 16:06:25 +0900
Subject: [PATCH] Store log file on disk for easier access (fixes #811)

---
 build.gradle                                  |  1 +
 .../service/SyncthingRunnable.java            | 37 +++++++++++++------
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/build.gradle b/build.gradle
index 76cd99ae..8d66a269 100644
--- a/build.gradle
+++ b/build.gradle
@@ -26,6 +26,7 @@ dependencies {
     compile 'com.google.code.gson:gson:2.8.0'
     compile 'org.mindrot:jbcrypt:0.3m'
     compile 'com.google.guava:guava:20.0'
+    compile 'com.annimon:stream:1.1.4'
     androidTestCompile 'com.android.support.test:rules:0.5'
 }
 
diff --git a/src/main/java/com/nutomic/syncthingandroid/service/SyncthingRunnable.java b/src/main/java/com/nutomic/syncthingandroid/service/SyncthingRunnable.java
index 659c0645..8244242b 100644
--- a/src/main/java/com/nutomic/syncthingandroid/service/SyncthingRunnable.java
+++ b/src/main/java/com/nutomic/syncthingandroid/service/SyncthingRunnable.java
@@ -9,6 +9,9 @@ import android.preference.PreferenceManager;
 import android.text.TextUtils;
 import android.util.Log;
 
+import com.annimon.stream.Stream;
+import com.google.common.base.Charsets;
+import com.google.common.io.Files;
 import com.nutomic.syncthingandroid.BuildConfig;
 
 import java.io.BufferedReader;
@@ -30,29 +33,22 @@ import eu.chainfire.libsuperuser.Shell;
 public class SyncthingRunnable implements Runnable {
 
     private static final String TAG = "SyncthingRunnable";
-
     private static final String TAG_NATIVE = "SyncthingNativeCode";
-
     private static final String TAG_NICE = "SyncthingRunnableIoNice";
-
     private static final String TAG_KILL = "SyncthingRunnableKill";
-
     public static final String UNIT_TEST_PATH = "was running";
-
     /**
      * Path to the native, integrated syncthing binary, relative to the data folder
      */
     public static final String BINARY_NAME = "lib/libsyncthing.so";
+    private static final int LOG_FILE_MAX_LINES = 1000;
 
     private static final AtomicReference<Process> mSyncthing = new AtomicReference<>();
-
     private final Context mContext;
-
     private final String mSyncthingBinary;
-
     private String[] mCommand;
-
     private String mErrorLog;
+    private final File mLogFile;
 
     public enum Command {
         generate, // Generate keys, a config file and immediately exit.
@@ -68,6 +64,7 @@ public class SyncthingRunnable implements Runnable {
     public SyncthingRunnable(Context context, Command command) {
         mContext = context;
         mSyncthingBinary = mContext.getApplicationInfo().dataDir + "/" + BINARY_NAME;
+        mLogFile = new File(mContext.getExternalFilesDir(null), "syncthing.log");
         switch (command) {
             case generate:
                 mCommand = new String[]{ mSyncthingBinary, "-generate", mContext.getFilesDir().toString() };
@@ -92,10 +89,12 @@ public class SyncthingRunnable implements Runnable {
         mContext = context;
         mSyncthingBinary = mContext.getApplicationInfo().dataDir + "/" + BINARY_NAME;
         mCommand = manualCommand;
+        mLogFile = new File(mContext.getExternalFilesDir(null), "syncthing.log");
     }
 
     @Override
     public void run() {
+        trimLogFile();
         SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(mContext);
         int ret;
         // Make sure Syncthing is executable
@@ -327,14 +326,16 @@ public class SyncthingRunnable implements Runnable {
     private Thread log(final InputStream is, final int priority, final boolean saveLog) {
         Thread t = new Thread(() -> {
             try {
-                InputStreamReader isr = new InputStreamReader(is, "UTF-8");
+                InputStreamReader isr = new InputStreamReader(is, Charsets.UTF_8);
                 BufferedReader br = new BufferedReader(isr);
                 String line;
                 while ((line = br.readLine()) != null) {
                     Log.println(priority, TAG_NATIVE, line);
 
-                    if (saveLog)
+                    if (saveLog) {
                         mErrorLog += line + "\n";
+                        Files.append(line + "\n", mLogFile, Charsets.UTF_8);
+                    }
                 }
             } catch (IOException e) {
                 Log.w(TAG, "Failed to read Syncthing's command line output", e);
@@ -344,4 +345,18 @@ public class SyncthingRunnable implements Runnable {
         return t;
     }
 
+    /**
+     * Only keep last {@link #LOG_FILE_MAX_LINES} lines in log file, to avoid bloat.
+     */
+    private void trimLogFile() {
+        try {
+            String lines = Stream.of(Files.readLines(mLogFile, Charsets.UTF_8))
+                    .limit(LOG_FILE_MAX_LINES)
+                    .reduce("", (a, b) -> a + b + "\n");
+            Files.write(lines, mLogFile, Charsets.UTF_8);
+        } catch (IOException e) {
+            Log.w(TAG, "Failed to trim log file", e);
+        }
+    }
+
 }