MimeUtils.java

  1/*
  2 * Copyright (C) 2010 The Android Open Source Project
  3 *
  4 * Licensed under the Apache License, Version 2.0 (the "License");
  5 * you may not use this file except in compliance with the License.
  6 * You may obtain a copy of the License at
  7 *
  8 *      http://www.apache.org/licenses/LICENSE-2.0
  9 *
 10 * Unless required by applicable law or agreed to in writing, software
 11 * distributed under the License is distributed on an "AS IS" BASIS,
 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 13 * See the License for the specific language governing permissions and
 14 * limitations under the License.
 15 */
 16package eu.siacs.conversations.utils;
 17
 18import android.content.Context;
 19import android.database.Cursor;
 20import android.net.Uri;
 21import android.provider.OpenableColumns;
 22import android.util.Log;
 23
 24import com.google.common.base.Strings;
 25import com.google.common.collect.ImmutableList;
 26
 27import java.io.File;
 28import java.io.FileInputStream;
 29import java.io.IOException;
 30import java.io.InputStream;
 31import java.util.Arrays;
 32import java.util.Collection;
 33import java.util.HashMap;
 34import java.util.List;
 35import java.util.Map;
 36import java.util.Properties;
 37
 38import eu.siacs.conversations.Config;
 39import eu.siacs.conversations.entities.Transferable;
 40import eu.siacs.conversations.worker.ExportBackupWorker;
 41
 42/**
 43 * Utilities for dealing with MIME types.
 44 * Used to implement java.net.URLConnection and android.webkit.MimeTypeMap.
 45 */
 46public final class MimeUtils {
 47
 48    public static final List<String> AMBIGUOUS_CONTAINER_FORMATS = ImmutableList.of(
 49            "application/ogg",
 50            "video/3gpp", // .3gp files can contain audio, video or both
 51            "video/3gpp2"
 52    );
 53
 54    private static final Map<String, String> mimeTypeToExtensionMap = new HashMap<>();
 55    private static final Map<String, String> extensionToMimeTypeMap = new HashMap<>();
 56
 57    static {
 58        // The following table is based on /etc/mime.types data minus
 59        // chemical/* MIME types and MIME types that don't map to any
 60        // file extensions. We also exclude top-level domain names to
 61        // deal with cases like:
 62        //
 63        // mail.google.com/a/google.com
 64        //
 65        // and "active" MIME types (due to potential security issues).
 66        // Note that this list is _not_ in alphabetical order and must not be sorted.
 67        // The "most popular" extension must come first, so that it's the one returned
 68        // by guessExtensionFromMimeType.
 69        add("application/andrew-inset", "ez");
 70        add("application/dsptype", "tsp");
 71        add("application/json", "json");
 72        add("application/epub+zip", "epub");
 73        add("application/gpx+xml", "gpx");
 74        add("application/hta", "hta");
 75        add("application/mac-binhex40", "hqx");
 76        add("application/mathematica", "nb");
 77        add("application/msaccess", "mdb");
 78        add("application/oda", "oda");
 79        add("application/ogg", "ogg");
 80        add("application/pdf", "pdf");
 81        add("application/pgp-keys", "key");
 82        add("application/pgp-signature", "pgp");
 83        add("application/pics-rules", "prf");
 84        add("application/pkix-cert", "cer");
 85        add("application/rar", "rar");
 86        add("application/rdf+xml", "rdf");
 87        add("application/rss+xml", "rss");
 88        add("application/zip", "zip");
 89        add("application/vnd.amazon.mobi8-ebook", "azw3");
 90        add("application/vnd.amazon.mobi8-ebook", "azw");
 91        add("application/vnd.amazon.mobi8-ebook", "kfx");
 92        add("application/vnd.android.package-archive", "apk");
 93        add("application/vnd.cinderella", "cdy");
 94        add(ExportBackupWorker.MIME_TYPE, "ceb");
 95        add("application/vnd.ms-pki.stl", "stl");
 96        add("application/vnd.oasis.opendocument.database", "odb");
 97        add("application/vnd.oasis.opendocument.formula", "odf");
 98        add("application/vnd.oasis.opendocument.graphics", "odg");
 99        add("application/vnd.oasis.opendocument.graphics-template", "otg");
100        add("application/vnd.oasis.opendocument.image", "odi");
101        add("application/vnd.oasis.opendocument.spreadsheet", "ods");
102        add("application/vnd.oasis.opendocument.spreadsheet-template", "ots");
103        add("application/vnd.oasis.opendocument.text", "odt");
104        add("application/vnd.oasis.opendocument.text-master", "odm");
105        add("application/vnd.oasis.opendocument.text-template", "ott");
106        add("application/vnd.oasis.opendocument.text-web", "oth");
107        add("application/vnd.google-earth.kml+xml", "kml");
108        add("application/vnd.google-earth.kmz", "kmz");
109        add("application/msword", "doc");
110        add("application/msword", "dot");
111        add("application/vnd.openxmlformats-officedocument.wordprocessingml.document", "docx");
112        add("application/vnd.openxmlformats-officedocument.wordprocessingml.template", "dotx");
113        add("application/vnd.ms-excel", "xls");
114        add("application/vnd.ms-excel", "xlt");
115        add("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "xlsx");
116        add("application/vnd.openxmlformats-officedocument.spreadsheetml.template", "xltx");
117        add("application/vnd.ms-powerpoint", "ppt");
118        add("application/vnd.ms-powerpoint", "pot");
119        add("application/vnd.ms-powerpoint", "pps");
120        add("application/vnd.openxmlformats-officedocument.presentationml.presentation", "pptx");
121        add("application/vnd.openxmlformats-officedocument.presentationml.template", "potx");
122        add("application/vnd.openxmlformats-officedocument.presentationml.slideshow", "ppsx");
123        add("application/vnd.rim.cod", "cod");
124        add("application/vnd.smaf", "mmf");
125        add("application/vnd.stardivision.calc", "sdc");
126        add("application/vnd.stardivision.draw", "sda");
127        add("application/vnd.stardivision.impress", "sdd");
128        add("application/vnd.stardivision.impress", "sdp");
129        add("application/vnd.stardivision.math", "smf");
130        add("application/vnd.stardivision.writer", "sdw");
131        add("application/vnd.stardivision.writer", "vor");
132        add("application/vnd.stardivision.writer-global", "sgl");
133        add("application/vnd.sun.xml.calc", "sxc");
134        add("application/vnd.sun.xml.calc.template", "stc");
135        add("application/vnd.sun.xml.draw", "sxd");
136        add("application/vnd.sun.xml.draw.template", "std");
137        add("application/vnd.sun.xml.impress", "sxi");
138        add("application/vnd.sun.xml.impress.template", "sti");
139        add("application/vnd.sun.xml.math", "sxm");
140        add("application/vnd.sun.xml.writer", "sxw");
141        add("application/vnd.sun.xml.writer.global", "sxg");
142        add("application/vnd.sun.xml.writer.template", "stw");
143        add("application/vnd.visio", "vsd");
144        add("application/x-7z-compressed","7z");
145        add("application/x-abiword", "abw");
146        add("application/x-apple-diskimage", "dmg");
147        add("application/x-bcpio", "bcpio");
148        add("application/x-bittorrent", "torrent");
149        add("application/x-cdf", "cdf");
150        add("application/x-cdlink", "vcd");
151        add("application/x-chess-pgn", "pgn");
152        add("application/x-cpio", "cpio");
153        add("application/x-debian-package", "deb");
154        add("application/x-debian-package", "udeb");
155        add("application/x-director", "dcr");
156        add("application/x-director", "dir");
157        add("application/x-director", "dxr");
158        add("application/x-dms", "dms");
159        add("application/x-doom", "wad");
160        add("application/x-dvi", "dvi");
161        add("application/x-font", "pfa");
162        add("application/x-font", "pfb");
163        add("application/x-font", "gsf");
164        add("application/x-font", "pcf");
165        add("application/x-font", "pcf.Z");
166        add("application/x-freemind", "mm");
167        // application/futuresplash isn't IANA, so application/x-futuresplash should come first.
168        add("application/x-futuresplash", "spl");
169        add("application/futuresplash", "spl");
170        add("application/x-gnumeric", "gnumeric");
171        add("application/x-go-sgf", "sgf");
172        add("application/x-graphing-calculator", "gcf");
173        add("application/x-gtar", "tgz");
174        add("application/x-gtar", "gtar");
175        add("application/x-gtar", "taz");
176        add("application/x-hdf", "hdf");
177        add("application/x-ica", "ica");
178        add("application/x-internet-signup", "ins");
179        add("application/x-internet-signup", "isp");
180        add("application/x-iphone", "iii");
181        add("application/x-iso9660-image", "iso");
182        add("application/x-jmol", "jmz");
183        add("application/x-kchart", "chrt");
184        add("application/x-killustrator", "kil");
185        add("application/x-koan", "skp");
186        add("application/x-koan", "skd");
187        add("application/x-koan", "skt");
188        add("application/x-koan", "skm");
189        add("application/x-kpresenter", "kpr");
190        add("application/x-kpresenter", "kpt");
191        add("application/x-kspread", "ksp");
192        add("application/x-kword", "kwd");
193        add("application/x-kword", "kwt");
194        add("application/x-latex", "latex");
195        add("application/x-lha", "lha");
196        add("application/x-lzh", "lzh");
197        add("application/x-lzx", "lzx");
198        add("application/x-maker", "frm");
199        add("application/x-maker", "maker");
200        add("application/x-maker", "frame");
201        add("application/x-maker", "fb");
202        add("application/x-maker", "book");
203        add("application/x-maker", "fbdoc");
204        add("application/x-mif", "mif");
205        add("application/x-mobipocket-ebook", "mobi");
206        add("application/x-ms-wmd", "wmd");
207        add("application/x-ms-wmz", "wmz");
208        add("application/x-msi", "msi");
209        add("application/x-ns-proxy-autoconfig", "pac");
210        add("application/x-nwc", "nwc");
211        add("application/x-object", "o");
212        add("application/x-oz-application", "oza");
213        add("application/x-pem-file", "pem");
214        add("application/x-pkcs12", "p12");
215        add("application/x-pkcs12", "pfx");
216        add("application/x-pkcs7-certreqresp", "p7r");
217        add("application/x-pkcs7-crl", "crl");
218        add("application/x-quicktimeplayer", "qtl");
219        add("application/x-shar", "shar");
220        add("application/x-shockwave-flash", "swf");
221        add("application/x-stuffit", "sit");
222        add("application/x-sv4cpio", "sv4cpio");
223        add("application/x-sv4crc", "sv4crc");
224        add("application/x-tar", "tar");
225        add("application/x-texinfo", "texinfo");
226        add("application/x-texinfo", "texi");
227        add("application/x-troff", "t");
228        add("application/x-troff", "roff");
229        add("application/x-troff-man", "man");
230        add("application/x-ustar", "ustar");
231        add("application/x-wais-source", "src");
232        add("application/x-wingz", "wz");
233        add("application/x-webarchive", "webarchive");
234        add("application/x-webarchive-xml", "webarchivexml");
235        add("application/x-x509-ca-cert", "crt");
236        add("application/x-x509-user-cert", "crt");
237        add("application/x-x509-server-cert", "crt");
238        add("application/x-xcf", "xcf");
239        add("application/x-xfig", "fig");
240        add("application/webxdc+zip", "xdc");
241        add("application/xhtml+xml", "xhtml");
242        add("video/3gpp", "3gpp");
243        add("video/3gpp", "3gp");
244        add("video/3gpp2", "3gpp2");
245        add("video/3gpp2", "3g2");
246        add("audio/3gpp", "3gpp");
247        add("audio/3gpp", "3gp");
248        add("audio/aac", "aac");
249        add("audio/aac-adts", "aac");
250        add("audio/amr", "amr");
251        add("audio/amr-wb", "awb");
252        add("audio/basic", "snd");
253        add("audio/flac", "flac");
254        add("application/x-flac", "flac");
255        add("audio/imelody", "imy");
256        add("audio/midi", "mid");
257        add("audio/midi", "midi");
258        add("audio/midi", "ota");
259        add("audio/midi", "kar");
260        add("audio/midi", "rtttl");
261        add("audio/midi", "xmf");
262        add("audio/mobile-xmf", "mxmf");
263        // add ".mp3" first so it will be the default for guessExtensionFromMimeType
264        add("audio/mpeg", "mp3");
265        add("audio/mpeg", "mpga");
266        add("audio/mpeg", "mpega");
267        add("audio/mpeg", "mp2");
268        add("audio/mp4", "m4a");
269        add("audio/x-m4b", "m4b");
270        add("audio/mpegurl", "m3u");
271        add("audio/ogg", "oga");
272        add("audio/ogg; codecs=opus", "opus"); // opus in ogg container
273        add("audio/opus", "opus"); // audio/opus for containerless opus
274        add("audio/prs.sid", "sid");
275        add("audio/x-aiff", "aif");
276        add("audio/x-aiff", "aiff");
277        add("audio/x-aiff", "aifc");
278        add("audio/x-gsm", "gsm");
279        add("audio/x-matroska", "mka");
280        add("audio/x-mpegurl", "m3u");
281        add("audio/x-ms-wma", "wma");
282        add("audio/x-ms-wax", "wax");
283        add("audio/x-pn-realaudio", "ra");
284        add("audio/x-pn-realaudio", "rm");
285        add("audio/x-pn-realaudio", "ram");
286        add("audio/x-realaudio", "ra");
287        add("audio/x-scpls", "pls");
288        add("audio/x-sd2", "sd2");
289        add("audio/x-wav", "wav");
290        // image/bmp isn't IANA, so image/x-ms-bmp should come first.
291        add("image/x-ms-bmp", "bmp");
292        add("image/bmp", "bmp");
293        add("image/gif", "gif");
294        // image/ico isn't IANA, so image/x-icon should come first.
295        add("image/x-icon", "ico");
296        add("image/ico", "cur");
297        add("image/ico", "ico");
298        add("image/ief", "ief");
299        add("image/heic", "heic");
300        add("image/heif", "heif");
301        add("image/avif", "avif");
302        // add ".jpg" first so it will be the default for guessExtensionFromMimeType
303        add("image/jpeg", "jpg");
304        add("image/jpeg", "jpeg");
305        add("image/jpeg", "jpe");
306        add("image/jpeg", "jfif");
307        add("image/jpeg", "jif");
308        add("image/pcx", "pcx");
309        add("image/png", "png");
310        add("image/svg+xml", "svg");
311        add("image/svg+xml", "svgz");
312        add("image/tiff", "tiff");
313        add("image/tiff", "tif");
314        add("image/vnd.djvu", "djvu");
315        add("image/vnd.djvu", "djv");
316        add("image/vnd.wap.wbmp", "wbmp");
317        add("image/webp", "webp");
318        add("image/x-cmu-raster", "ras");
319        add("image/x-coreldraw", "cdr");
320        add("image/x-coreldrawpattern", "pat");
321        add("image/x-coreldrawtemplate", "cdt");
322        add("image/x-corelphotopaint", "cpt");
323        add("image/x-jg", "art");
324        add("image/x-jng", "jng");
325        add("image/x-photoshop", "psd");
326        add("image/x-portable-anymap", "pnm");
327        add("image/x-portable-bitmap", "pbm");
328        add("image/x-portable-graymap", "pgm");
329        add("image/x-portable-pixmap", "ppm");
330        add("image/x-rgb", "rgb");
331        add("image/x-xbitmap", "xbm");
332        add("image/x-xpixmap", "xpm");
333        add("image/x-xwindowdump", "xwd");
334        add("message/rfc822","eml");
335        add("message/rfc822","mime");
336        add("model/iges", "igs");
337        add("model/iges", "iges");
338        add("model/mesh", "msh");
339        add("model/mesh", "mesh");
340        add("model/mesh", "silo");
341        add("text/calendar", "ics");
342        add("text/calendar", "icz");
343        add("text/comma-separated-values", "csv");
344        add("text/css", "css");
345        add("text/html", "htm");
346        add("text/html", "html");
347        add("text/h323", "323");
348        add("text/iuls", "uls");
349        add("text/javascript", "js");
350        add("text/mathml", "mml");
351        // add ".txt" first so it will be the default for guessExtensionFromMimeType
352        add("text/plain", "txt");
353        add("text/plain", "asc");
354        add("text/plain", "text");
355        add("text/plain", "diff");
356        add("text/plain", "po");     // reserve "pot" for vnd.ms-powerpoint
357        add("text/richtext", "rtx");
358        add("text/rtf", "rtf");
359        add("text/text", "phps");
360        add("text/tab-separated-values", "tsv");
361        add("text/xml", "xml");
362        add("text/x-bibtex", "bib");
363        add("text/x-boo", "boo");
364        add("text/x-c++hdr", "hpp");
365        add("text/x-c++hdr", "h++");
366        add("text/x-c++hdr", "hxx");
367        add("text/x-c++hdr", "hh");
368        add("text/x-c++src", "cpp");
369        add("text/x-c++src", "c++");
370        add("text/x-c++src", "cc");
371        add("text/x-c++src", "cxx");
372        add("text/x-chdr", "h");
373        add("text/x-component", "htc");
374        add("text/x-csh", "csh");
375        add("text/x-csrc", "c");
376        add("text/x-dsrc", "d");
377        add("text/x-haskell", "hs");
378        add("text/x-java", "java");
379        add("text/x-literate-haskell", "lhs");
380        add("text/x-moc", "moc");
381        add("text/x-pascal", "p");
382        add("text/x-pascal", "pas");
383        add("text/x-pcs-gcd", "gcd");
384        add("text/x-setext", "etx");
385        add("text/x-tcl", "tcl");
386        add("text/x-tex", "tex");
387        add("text/x-tex", "ltx");
388        add("text/x-tex", "sty");
389        add("text/x-tex", "cls");
390        add("text/x-vcalendar", "vcs");
391        add("text/x-vcard", "vcf");
392        add("video/avi", "avi");
393        add("video/dl", "dl");
394        add("video/dv", "dif");
395        add("video/dv", "dv");
396        add("video/fli", "fli");
397        add("video/m4v", "m4v");
398        add("video/mp2ts", "ts");
399        add("video/ogg", "ogv");
400        add("video/mpeg", "mpeg");
401        add("video/mpeg", "mpg");
402        add("video/mpeg", "mpe");
403        add("video/mp4", "mp4");
404        add("video/mpeg", "VOB");
405        add("video/quicktime", "qt");
406        add("video/quicktime", "mov");
407        add("video/vnd.mpegurl", "mxu");
408        add("video/webm", "webm");
409        add("video/x-la-asf", "lsf");
410        add("video/x-la-asf", "lsx");
411        add("video/x-matroska", "mkv");
412        add("video/x-mng", "mng");
413        add("video/x-ms-asf", "asf");
414        add("video/x-ms-asf", "asx");
415        add("video/x-ms-wm", "wm");
416        add("video/x-ms-wmv", "wmv");
417        add("video/x-ms-wmx", "wmx");
418        add("video/x-ms-wvx", "wvx");
419        add("video/x-sgi-movie", "movie");
420        add("video/x-webex", "wrf");
421        add("x-conference/x-cooltalk", "ice");
422        add("x-epoc/x-sisx-app", "sisx");
423        applyOverrides();
424    }
425
426    // mime types that are more reliant by path
427    private static final Collection<String> PATH_PRECEDENCE_MIME_TYPE = Arrays.asList("audio/x-m4b");
428
429    private static void add(String mimeType, String extension) {
430        // If we have an existing x -> y mapping, we do not want to
431        // override it with another mapping x -> y2.
432        // If a mime type maps to several extensions
433        // the first extension added is considered the most popular
434        // so we do not want to overwrite it later.
435        if (!mimeTypeToExtensionMap.containsKey(mimeType)) {
436            mimeTypeToExtensionMap.put(mimeType, extension);
437        }
438        if (!extensionToMimeTypeMap.containsKey(extension)) {
439            extensionToMimeTypeMap.put(extension, mimeType);
440        }
441    }
442
443    private static InputStream getContentTypesPropertiesStream() {
444        // User override?
445        String userTable = System.getProperty("content.types.user.table");
446        if (userTable != null) {
447            File f = new File(userTable);
448            if (f.exists()) {
449                try {
450                    return new FileInputStream(f);
451                } catch (IOException ignored) {
452                }
453            }
454        }
455        // Standard location?
456        File f = new File(System.getProperty("java.home"), "lib" + File.separator + "content-types.properties");
457        if (f.exists()) {
458            try {
459                return new FileInputStream(f);
460            } catch (IOException ignored) {
461            }
462        }
463        return null;
464    }
465
466    /**
467     * This isn't what the RI does. The RI doesn't have hard-coded defaults, so supplying your
468     * own "content.types.user.table" means you don't get any of the built-ins, and the built-ins
469     * come from "$JAVA_HOME/lib/content-types.properties".
470     */
471    private static void applyOverrides() {
472        // Get the appropriate InputStream to read overrides from, if any.
473        InputStream stream = getContentTypesPropertiesStream();
474        if (stream == null) {
475            return;
476        }
477        try {
478            try {
479                // Read the properties file...
480                Properties overrides = new Properties();
481                overrides.load(stream);
482                // And translate its mapping to ours...
483                for (Map.Entry<Object, Object> entry : overrides.entrySet()) {
484                    String extension = (String) entry.getKey();
485                    String mimeType = (String) entry.getValue();
486                    add(mimeType, extension);
487                }
488            } finally {
489                stream.close();
490            }
491        } catch (IOException ignored) {
492        }
493    }
494
495    private MimeUtils() {
496    }
497
498    /**
499     * Returns true if the given MIME type has an entry in the map.
500     *
501     * @param mimeType A MIME type (i.e. text/plain)
502     * @return True iff there is a mimeType entry in the map.
503     */
504    public static boolean hasMimeType(String mimeType) {
505        if (mimeType == null || mimeType.isEmpty()) {
506            return false;
507        }
508        return mimeTypeToExtensionMap.containsKey(mimeType);
509    }
510
511    /**
512     * Returns the MIME type for the given extension.
513     *
514     * @param extension A file extension without the leading '.'
515     * @return The MIME type for the given extension or null iff there is none.
516     */
517    public static String guessMimeTypeFromExtension(String extension) {
518        if (extension == null || extension.isEmpty()) {
519            return null;
520        }
521        return extensionToMimeTypeMap.get(extension.toLowerCase());
522    }
523
524    /**
525     * Returns true if the given extension has a registered MIME type.
526     *
527     * @param extension A file extension without the leading '.'
528     * @return True iff there is an extension entry in the map.
529     */
530    public static boolean hasExtension(String extension) {
531        if (extension == null || extension.isEmpty()) {
532            return false;
533        }
534        return extensionToMimeTypeMap.containsKey(extension);
535    }
536
537    /**
538     * Returns the registered extension for the given MIME type. Note that some
539     * MIME types map to multiple extensions. This call will return the most
540     * common extension for the given MIME type.
541     *
542     * @param mimeType A MIME type (i.e. text/plain)
543     * @return The extension for the given MIME type or null iff there is none.
544     */
545    public static String guessExtensionFromMimeType(String mimeType) {
546        if (mimeType == null || mimeType.isEmpty()) {
547            return null;
548        }
549        return mimeTypeToExtensionMap.get(mimeType.split(";")[0]);
550    }
551
552    public static String guessMimeTypeFromUriAndMime(final Context context, final Uri uri, final String mime) {
553        Log.d(Config.LOGTAG, "guessMimeTypeFromUriAndMime(" + uri + "," + mime+")");
554        final String mimeFromUri = guessMimeTypeFromUri(context, uri);
555        Log.d(Config.LOGTAG,"mimeFromUri:"+mimeFromUri);
556        if (PATH_PRECEDENCE_MIME_TYPE.contains(mimeFromUri)) {
557            return mimeFromUri;
558        } else if (mime == null || mime.equals("application/octet-stream")) {
559            return mimeFromUri;
560        } else {
561            return mime;
562        }
563    }
564
565    public static String guessMimeTypeFromUri(final Context context, final Uri uri) {
566        if ("data".equals(uri.getScheme())) {
567            String[] parts = uri.getSchemeSpecificPart().split(",", 2);
568            String[] parts2 = parts[0].split(";", 2);
569            if (parts2.length > 0) return parts2[0];
570        }
571        final String mimeTypeContentResolver = guessFromContentResolver(context, uri);
572        final String mimeTypeFromQueryParameter = uri.isHierarchical() ? uri.getQueryParameter("mimeType") : null;
573        final String name = "content".equals(uri.getScheme()) ? getDisplayName(context, uri) : null;
574        final String mimeTypeFromName = Strings.isNullOrEmpty(name) ? null : guessFromPath(name);
575        final String path = uri.getPath();
576        final String mimeTypeFromPath = Strings.isNullOrEmpty(path) ? null : guessFromPath(path);
577        if (PATH_PRECEDENCE_MIME_TYPE.contains(mimeTypeFromName)) {
578            return mimeTypeFromName;
579        }
580        if (PATH_PRECEDENCE_MIME_TYPE.contains(mimeTypeFromPath)) {
581            return mimeTypeFromPath;
582        }
583        if (mimeTypeContentResolver != null && !"application/octet-stream".equals(mimeTypeContentResolver)) {
584            return mimeTypeContentResolver;
585        }
586        if (mimeTypeFromName != null) {
587            return mimeTypeFromName;
588        }
589        if (mimeTypeFromQueryParameter != null) {
590            return mimeTypeFromQueryParameter;
591        }
592        return mimeTypeFromPath;
593    }
594
595    private static String guessFromContentResolver(final Context context, final Uri uri) {
596        try {
597            return context.getContentResolver().getType(uri);
598        } catch (final Throwable e) {
599            return null;
600        }
601    }
602
603    private static String getDisplayName(final Context context, final Uri uri) {
604        try (final Cursor cursor = context.getContentResolver().query(uri, null, null, null, null)) {
605            if (cursor != null && cursor.moveToFirst()) {
606                final int index = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
607                if (index == -1) {
608                    return null;
609                }
610                return cursor.getString(index);
611            }
612        } catch (final Exception e) {
613            return null;
614        }
615        return null;
616    }
617
618    public static String guessFromPath(final String path) {
619        final int start = path.lastIndexOf('.') + 1;
620        if (start < path.length()) {
621            return MimeUtils.guessMimeTypeFromExtension(path.substring(start));
622        }
623        return null;
624    }
625
626    public static String extractRelevantExtension(final String path) {
627        return extractRelevantExtension(path, false);
628    }
629
630    public static String extractRelevantExtension(final String path, final boolean ignoreCryptoExtension) {
631        if (Strings.isNullOrEmpty(path)) {
632            return null;
633        }
634
635        final String filenameQueryAnchor = path.substring(path.lastIndexOf('/') + 1);
636        final String filenameQuery = cutBefore(filenameQueryAnchor, '#');
637        final String filename = cutBefore(filenameQuery, '?');
638        final int dotPosition = filename.lastIndexOf('.');
639
640        if (dotPosition == -1) {
641            return null;
642        }
643        final String extension = filename.substring(dotPosition + 1);
644        // we want the real file extension, not the crypto one
645        if (ignoreCryptoExtension && Transferable.VALID_CRYPTO_EXTENSIONS.contains(extension)) {
646            return extractRelevantExtension(filename.substring(0, dotPosition));
647        } else {
648            return extension;
649        }
650    }
651
652    private static String cutBefore(final String input, final char c) {
653        final int position = input.indexOf(c);
654        if (position > 0) {
655            return input.substring(0, position);
656        } else {
657            return input;
658        }
659    }
660}