Refactoring

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

@@ -26,7 +26,9 @@ import android.content.SharedPreferences;
 import android.net.Uri;
 import android.os.Build;
 import android.system.ErrnoException;
+import android.text.SpannableStringBuilder;
 import android.text.TextUtils;
+import android.text.style.ForegroundColorSpan;
 import android.util.Base64;
 
 import androidx.annotation.NonNull;
@@ -4743,6 +4745,110 @@ public class MessageHelper {
         return result.toArray(new InternetAddress[0]);
     }
 
+    static void getStructure(Part part, SpannableStringBuilder ssb, int level, int textColorLink) {
+        try {
+            Enumeration<Header> headers;
+            if (level == 0) {
+                List<Header> h = new ArrayList<>();
+
+                String[] cte = part.getHeader("Content-Transfer-Encoding");
+                if (cte != null)
+                    for (String header : cte)
+                        h.add(new Header("Content-Transfer-Encoding", header));
+
+                String[] ct = part.getHeader("Content-Type");
+                if (ct == null)
+                    h.add(new Header("Content-Type", "text/plain"));
+                else
+                    for (String header : ct)
+                        h.add(new Header("Content-Type", header));
+
+                headers = new Enumeration<Header>() {
+                    private int index = -1;
+
+                    @Override
+                    public boolean hasMoreElements() {
+                        return (index + 1 < h.size());
+                    }
+
+                    @Override
+                    public Header nextElement() {
+                        return h.get(++index);
+                    }
+                };
+            } else
+                headers = part.getAllHeaders();
+
+            while (headers.hasMoreElements()) {
+                Header header = headers.nextElement();
+                for (int i = 0; i < level; i++)
+                    ssb.append("  ");
+                int start = ssb.length();
+                ssb.append(header.getName());
+                ssb.setSpan(new ForegroundColorSpan(textColorLink), start, ssb.length(), 0);
+                ssb.append(": ").append(header.getValue()).append('\n');
+            }
+
+            for (int i = 0; i < level; i++)
+                ssb.append("  ");
+            int size = part.getSize();
+            ssb.append("Size: ")
+                    .append(size > 0 ? Helper.humanReadableByteCount(size) : "?")
+                    .append('\n');
+
+            if (BuildConfig.DEBUG &&
+                    !part.isMimeType("multipart/*")) {
+                Object content = part.getContent();
+                if (content instanceof String) {
+                    String text = (String) content;
+
+                    String charset;
+                    try {
+                        ContentType ct = new ContentType(part.getContentType());
+                        charset = ct.getParameter("charset");
+                    } catch (Throwable ignored) {
+                        charset = null;
+                    }
+                    if (charset == null)
+                        charset = StandardCharsets.ISO_8859_1.name();
+
+                    Charset cs = Charset.forName(charset);
+                    Charset detected = CharsetHelper.detect(text, cs);
+                    boolean isUtf8 = CharsetHelper.isUTF8(text.getBytes(cs));
+                    boolean isUtf16 = CharsetHelper.isUTF16(text.getBytes(cs));
+                    boolean isW1252 = !Objects.equals(text, CharsetHelper.utf8toW1252(text));
+
+                    for (int i = 0; i < level; i++)
+                        ssb.append("  ");
+
+                    ssb.append("Detected: ")
+                            .append(detected == null ? "?" : detected.toString())
+                            .append(" isUTF8=").append(Boolean.toString(isUtf8))
+                            .append(" isUTF16=").append(Boolean.toString(isUtf16))
+                            .append(" isW1252=").append(Boolean.toString(isW1252))
+                            .append('\n');
+                }
+            }
+
+            ssb.append('\n');
+
+            if (part.isMimeType("multipart/*")) {
+                Multipart multipart = (Multipart) part.getContent();
+                for (int i = 0; i < multipart.getCount(); i++)
+                    try {
+                        getStructure(multipart.getBodyPart(i), ssb, level + 1, textColorLink);
+                    } catch (Throwable ex) {
+                        Log.w(ex);
+                        ssb.append(ex.toString()).append('\n');
+                    }
+            }
+        } catch (Throwable ex) {
+            Log.w(ex);
+            ssb.append(ex.toString()).append('\n');
+        }
+    }
+
+
     static boolean isRemoved(Throwable ex) {
         while (ex != null) {
             if (ex instanceof MessageRemovedException ||