Refactoring

app/src/main/java/eu/faircode/email/DB.java

@@ -121,6 +121,7 @@ public abstract class DB extends RoomDatabase {
     private static int sPid;
     private static Context sContext;
     private static DB sInstance;
+    private static Boolean hasJson = null;
 
     static final String DB_NAME = "fairemail";
     static final int DEFAULT_QUERY_THREADS = 4; // AndroidX default thread count: 4
@@ -146,6 +147,57 @@ public abstract class DB extends RoomDatabase {
             "compile_options"
     ));
 
+    public static String getSqliteVersion() {
+        try (SQLiteDatabase db = SQLiteDatabase.create(null)) {
+            try (Cursor cursor = db.rawQuery(
+                    "SELECT sqlite_version() AS sqlite_version", null)) {
+                if (cursor.moveToNext())
+                    return cursor.getString(0);
+            }
+        } catch (Throwable ex) {
+            Log.e(ex);
+        }
+        return null;
+    }
+
+    public static boolean hasJson() {
+        return hasJson;
+    }
+
+    private static boolean _hasJson() {
+        try {
+            // https://www.sqlite.org/json1.html
+            // The JSON functions and operators are built into SQLite by default, as of SQLite version 3.38.0 (2022-02-22)
+            String version = getSqliteVersion();
+            if (version == null)
+                return false;
+
+            String[] parts = version.split("\\.");
+            if (parts.length == 0)
+                return false;
+
+            int[] numbers = new int[parts.length];
+            for (int i = 0; i < parts.length; i++)
+                numbers[i] = Integer.parseInt(parts[i]);
+
+            if (numbers[0] < 3)
+                return false;
+            if (numbers[0] > 3)
+                return true;
+
+            if (parts.length == 1)
+                return false;
+
+            if (numbers[1] < 38)
+                return false;
+
+            return true;
+        } catch (Throwable ex) {
+            Log.e(ex);
+            return false;
+        }
+    }
+
     @Override
     public void init(@NonNull DatabaseConfiguration configuration) {
         File dbfile = configuration.context.getDatabasePath(DB_NAME);
@@ -466,6 +518,8 @@ public abstract class DB extends RoomDatabase {
             Log.i("DB critical section end");
         }
 
+        hasJson = _hasJson();
+
         return sInstance;
     }
 

app/src/main/java/eu/faircode/email/DebugHelper.java

@@ -1808,11 +1808,8 @@ public class DebugHelper {
                 size += write(os, String.format("Database: %s\r\n",
                         context.getDatabasePath(DB.DB_NAME)));
 
-                try (Cursor cursor = SQLiteDatabase.create(null).rawQuery(
-                        "SELECT sqlite_version() AS sqlite_version", null)) {
-                    if (cursor.moveToNext())
-                        size += write(os, String.format("sqlite: %s\r\n", cursor.getString(0)));
-                }
+                size += write(os, String.format("sqlite: %s json: %b\r\n", DB.getSqliteVersion(), DB.hasJson()));
+
                 try {
                     TupleFtsStats stats = db.message().getFts();
                     size += write(os, String.format("fts: %d/%d %s\r\n", stats.fts, stats.total,