diff options
Diffstat (limited to 'java/com/android/voicemailomtp/mail/internet/MimeUtility.java')
-rw-r--r-- | java/com/android/voicemailomtp/mail/internet/MimeUtility.java | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/java/com/android/voicemailomtp/mail/internet/MimeUtility.java b/java/com/android/voicemailomtp/mail/internet/MimeUtility.java new file mode 100644 index 000000000..4d310b0f5 --- /dev/null +++ b/java/com/android/voicemailomtp/mail/internet/MimeUtility.java @@ -0,0 +1,416 @@ +/* + * Copyright (C) 2015 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package com.android.voicemailomtp.mail.internet; + +import android.text.TextUtils; +import android.util.Base64; +import android.util.Base64DataException; +import android.util.Base64InputStream; + +import com.android.voicemailomtp.mail.Body; +import com.android.voicemailomtp.mail.BodyPart; +import com.android.voicemailomtp.mail.Message; +import com.android.voicemailomtp.mail.MessagingException; +import com.android.voicemailomtp.mail.Multipart; +import com.android.voicemailomtp.mail.Part; +import com.android.voicemailomtp.VvmLog; + +import org.apache.commons.io.IOUtils; +import org.apache.james.mime4j.codec.EncoderUtil; +import org.apache.james.mime4j.decoder.DecoderUtil; +import org.apache.james.mime4j.decoder.QuotedPrintableInputStream; +import org.apache.james.mime4j.util.CharsetUtil; + +import java.io.ByteArrayOutputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.OutputStream; +import java.util.ArrayList; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +public class MimeUtility { + private static final String LOG_TAG = "Email"; + + public static final String MIME_TYPE_RFC822 = "message/rfc822"; + private final static Pattern PATTERN_CR_OR_LF = Pattern.compile("\r|\n"); + + /** + * Replace sequences of CRLF+WSP with WSP. Tries to preserve original string + * object whenever possible. + */ + public static String unfold(String s) { + if (s == null) { + return null; + } + Matcher patternMatcher = PATTERN_CR_OR_LF.matcher(s); + if (patternMatcher.find()) { + patternMatcher.reset(); + s = patternMatcher.replaceAll(""); + } + return s; + } + + public static String decode(String s) { + if (s == null) { + return null; + } + return DecoderUtil.decodeEncodedWords(s); + } + + public static String unfoldAndDecode(String s) { + return decode(unfold(s)); + } + + // TODO implement proper foldAndEncode + // NOTE: When this really works, we *must* remove all calls to foldAndEncode2() to prevent + // duplication of encoding. + public static String foldAndEncode(String s) { + return s; + } + + /** + * INTERIM version of foldAndEncode that will be used only by Subject: headers. + * This is safer than implementing foldAndEncode() (see above) and risking unknown damage + * to other headers. + * + * TODO: Copy this code to foldAndEncode(), get rid of this function, confirm all working OK. + * + * @param s original string to encode and fold + * @param usedCharacters number of characters already used up by header name + + * @return the String ready to be transmitted + */ + public static String foldAndEncode2(String s, int usedCharacters) { + // james.mime4j.codec.EncoderUtil.java + // encode: encodeIfNecessary(text, usage, numUsedInHeaderName) + // Usage.TEXT_TOKENlooks like the right thing for subjects + // use WORD_ENTITY for address/names + + String encoded = EncoderUtil.encodeIfNecessary(s, EncoderUtil.Usage.TEXT_TOKEN, + usedCharacters); + + return fold(encoded, usedCharacters); + } + + /** + * INTERIM: From newer version of org.apache.james (but we don't want to import + * the entire MimeUtil class). + * + * Splits the specified string into a multiple-line representation with + * lines no longer than 76 characters (because the line might contain + * encoded words; see <a href='http://www.faqs.org/rfcs/rfc2047.html'>RFC + * 2047</a> section 2). If the string contains non-whitespace sequences + * longer than 76 characters a line break is inserted at the whitespace + * character following the sequence resulting in a line longer than 76 + * characters. + * + * @param s + * string to split. + * @param usedCharacters + * number of characters already used up. Usually the number of + * characters for header field name plus colon and one space. + * @return a multiple-line representation of the given string. + */ + public static String fold(String s, int usedCharacters) { + final int maxCharacters = 76; + + final int length = s.length(); + if (usedCharacters + length <= maxCharacters) + return s; + + StringBuilder sb = new StringBuilder(); + + int lastLineBreak = -usedCharacters; + int wspIdx = indexOfWsp(s, 0); + while (true) { + if (wspIdx == length) { + sb.append(s.substring(Math.max(0, lastLineBreak))); + return sb.toString(); + } + + int nextWspIdx = indexOfWsp(s, wspIdx + 1); + + if (nextWspIdx - lastLineBreak > maxCharacters) { + sb.append(s.substring(Math.max(0, lastLineBreak), wspIdx)); + sb.append("\r\n"); + lastLineBreak = wspIdx; + } + + wspIdx = nextWspIdx; + } + } + + /** + * INTERIM: From newer version of org.apache.james (but we don't want to import + * the entire MimeUtil class). + * + * Search for whitespace. + */ + private static int indexOfWsp(String s, int fromIndex) { + final int len = s.length(); + for (int index = fromIndex; index < len; index++) { + char c = s.charAt(index); + if (c == ' ' || c == '\t') + return index; + } + return len; + } + + /** + * Returns the named parameter of a header field. If name is null the first + * parameter is returned, or if there are no additional parameters in the + * field the entire field is returned. Otherwise the named parameter is + * searched for in a case insensitive fashion and returned. If the parameter + * cannot be found the method returns null. + * + * TODO: quite inefficient with the inner trimming & splitting. + * TODO: Also has a latent bug: uses "startsWith" to match the name, which can false-positive. + * TODO: The doc says that for a null name you get the first param, but you get the header. + * Should probably just fix the doc, but if other code assumes that behavior, fix the code. + * TODO: Need to decode %-escaped strings, as in: filename="ab%22d". + * ('+' -> ' ' conversion too? check RFC) + * + * @param header + * @param name + * @return the entire header (if name=null), the found parameter, or null + */ + public static String getHeaderParameter(String header, String name) { + if (header == null) { + return null; + } + String[] parts = unfold(header).split(";"); + if (name == null) { + return parts[0].trim(); + } + String lowerCaseName = name.toLowerCase(); + for (String part : parts) { + if (part.trim().toLowerCase().startsWith(lowerCaseName)) { + String[] parameterParts = part.split("=", 2); + if (parameterParts.length < 2) { + return null; + } + String parameter = parameterParts[1].trim(); + if (parameter.startsWith("\"") && parameter.endsWith("\"")) { + return parameter.substring(1, parameter.length() - 1); + } else { + return parameter; + } + } + } + return null; + } + + /** + * Reads the Part's body and returns a String based on any charset conversion that needed + * to be done. + * @param part The part containing a body + * @return a String containing the converted text in the body, or null if there was no text + * or an error during conversion. + */ + public static String getTextFromPart(Part part) { + try { + if (part != null && part.getBody() != null) { + InputStream in = part.getBody().getInputStream(); + String mimeType = part.getMimeType(); + if (mimeType != null && MimeUtility.mimeTypeMatches(mimeType, "text/*")) { + /* + * Now we read the part into a buffer for further processing. Because + * the stream is now wrapped we'll remove any transfer encoding at this point. + */ + ByteArrayOutputStream out = new ByteArrayOutputStream(); + IOUtils.copy(in, out); + in.close(); + in = null; // we want all of our memory back, and close might not release + + /* + * We've got a text part, so let's see if it needs to be processed further. + */ + String charset = getHeaderParameter(part.getContentType(), "charset"); + if (charset != null) { + /* + * See if there is conversion from the MIME charset to the Java one. + */ + charset = CharsetUtil.toJavaCharset(charset); + } + /* + * No encoding, so use us-ascii, which is the standard. + */ + if (charset == null) { + charset = "ASCII"; + } + /* + * Convert and return as new String + */ + String result = out.toString(charset); + out.close(); + return result; + } + } + + } + catch (OutOfMemoryError oom) { + /* + * If we are not able to process the body there's nothing we can do about it. Return + * null and let the upper layers handle the missing content. + */ + VvmLog.e(LOG_TAG, "Unable to getTextFromPart " + oom.toString()); + } + catch (Exception e) { + /* + * If we are not able to process the body there's nothing we can do about it. Return + * null and let the upper layers handle the missing content. + */ + VvmLog.e(LOG_TAG, "Unable to getTextFromPart " + e.toString()); + } + return null; + } + + /** + * Returns true if the given mimeType matches the matchAgainst specification. The comparison + * ignores case and the matchAgainst string may include "*" for a wildcard (e.g. "image/*"). + * + * @param mimeType A MIME type to check. + * @param matchAgainst A MIME type to check against. May include wildcards. + * @return true if the mimeType matches + */ + public static boolean mimeTypeMatches(String mimeType, String matchAgainst) { + Pattern p = Pattern.compile(matchAgainst.replaceAll("\\*", "\\.\\*"), + Pattern.CASE_INSENSITIVE); + return p.matcher(mimeType).matches(); + } + + /** + * Returns true if the given mimeType matches any of the matchAgainst specifications. The + * comparison ignores case and the matchAgainst strings may include "*" for a wildcard + * (e.g. "image/*"). + * + * @param mimeType A MIME type to check. + * @param matchAgainst An array of MIME types to check against. May include wildcards. + * @return true if the mimeType matches any of the matchAgainst strings + */ + public static boolean mimeTypeMatches(String mimeType, String[] matchAgainst) { + for (String matchType : matchAgainst) { + if (mimeTypeMatches(mimeType, matchType)) { + return true; + } + } + return false; + } + + /** + * Given an input stream and a transfer encoding, return a wrapped input stream for that + * encoding (or the original if none is required) + * @param in the input stream + * @param contentTransferEncoding the content transfer encoding + * @return a properly wrapped stream + */ + public static InputStream getInputStreamForContentTransferEncoding(InputStream in, + String contentTransferEncoding) { + if (contentTransferEncoding != null) { + contentTransferEncoding = + MimeUtility.getHeaderParameter(contentTransferEncoding, null); + if ("quoted-printable".equalsIgnoreCase(contentTransferEncoding)) { + in = new QuotedPrintableInputStream(in); + } + else if ("base64".equalsIgnoreCase(contentTransferEncoding)) { + in = new Base64InputStream(in, Base64.DEFAULT); + } + } + return in; + } + + /** + * Removes any content transfer encoding from the stream and returns a Body. + */ + public static Body decodeBody(InputStream in, String contentTransferEncoding) + throws IOException { + /* + * We'll remove any transfer encoding by wrapping the stream. + */ + in = getInputStreamForContentTransferEncoding(in, contentTransferEncoding); + BinaryTempFileBody tempBody = new BinaryTempFileBody(); + OutputStream out = tempBody.getOutputStream(); + try { + IOUtils.copy(in, out); + } catch (Base64DataException bde) { + // TODO Need to fix this somehow + //String warning = "\n\n" + Email.getMessageDecodeErrorString(); + //out.write(warning.getBytes()); + } finally { + out.close(); + } + return tempBody; + } + + /** + * Recursively scan a Part (usually a Message) and sort out which of its children will be + * "viewable" and which will be attachments. + * + * @param part The part to be broken down + * @param viewables This arraylist will be populated with all parts that appear to be + * the "message" (e.g. text/plain & text/html) + * @param attachments This arraylist will be populated with all parts that appear to be + * attachments (including inlines) + * @throws MessagingException + */ + public static void collectParts(Part part, ArrayList<Part> viewables, + ArrayList<Part> attachments) throws MessagingException { + String disposition = part.getDisposition(); + String dispositionType = MimeUtility.getHeaderParameter(disposition, null); + // If a disposition is not specified, default to "inline" + boolean inline = + TextUtils.isEmpty(dispositionType) || "inline".equalsIgnoreCase(dispositionType); + // The lower-case mime type + String mimeType = part.getMimeType().toLowerCase(); + + if (part.getBody() instanceof Multipart) { + // If the part is Multipart but not alternative it's either mixed or + // something we don't know about, which means we treat it as mixed + // per the spec. We just process its pieces recursively. + MimeMultipart mp = (MimeMultipart)part.getBody(); + boolean foundHtml = false; + if (mp.getSubTypeForTest().equals("alternative")) { + for (int i = 0; i < mp.getCount(); i++) { + if (mp.getBodyPart(i).isMimeType("text/html")) { + foundHtml = true; + break; + } + } + } + for (int i = 0; i < mp.getCount(); i++) { + // See if we have text and html + BodyPart bp = mp.getBodyPart(i); + // If there's html, don't bother loading text + if (foundHtml && bp.isMimeType("text/plain")) { + continue; + } + collectParts(bp, viewables, attachments); + } + } else if (part.getBody() instanceof Message) { + // If the part is an embedded message we just continue to process + // it, pulling any viewables or attachments into the running list. + Message message = (Message)part.getBody(); + collectParts(message, viewables, attachments); + } else if (inline && (mimeType.startsWith("text") || (mimeType.startsWith("image")))) { + // We'll treat text and images as viewables + viewables.add(part); + } else { + // Everything else is an attachment. + attachments.add(part); + } + } +} |