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;
 23import com.google.common.base.Strings;
 24import com.google.common.collect.ImmutableList;
 25import eu.siacs.conversations.Config;
 26import eu.siacs.conversations.entities.Transferable;
 27import eu.siacs.conversations.worker.ExportBackupWorker;
 28import java.io.File;
 29import java.io.FileInputStream;
 30import java.io.IOException;
 31import java.io.InputStream;
 32import java.util.Arrays;
 33import java.util.Collection;
 34import java.util.HashMap;
 35import java.util.List;
 36import java.util.Map;
 37import java.util.Properties;
 38
 39/**
 40 * Utilities for dealing with MIME types. Used to implement java.net.URLConnection and
 41 * android.webkit.MimeTypeMap.
 42 */
 43public final class MimeUtils {
 44
 45    public static final List<String> AMBIGUOUS_CONTAINER_FORMATS =
 46            ImmutableList.of(
 47                    "application/ogg",
 48                    "video/3gpp", // .3gp files can contain audio, video or both
 49                    "video/3gpp2");
 50
 51    private static final Map<String, String> mimeTypeToExtensionMap = new HashMap<>();
 52    private static final Map<String, String> extensionToMimeTypeMap = new HashMap<>();
 53
 54    static {
 55        // The following table is based on /etc/mime.types data minus
 56        // chemical/* MIME types and MIME types that don't map to any
 57        // file extensions. We also exclude top-level domain names to
 58        // deal with cases like:
 59        //
 60        // mail.google.com/a/google.com
 61        //
 62        // and "active" MIME types (due to potential security issues).
 63        // Note that this list is _not_ in alphabetical order and must not be sorted.
 64        // The "most popular" extension must come first, so that it's the one returned
 65        // by guessExtensionFromMimeType.
 66        add("application/andrew-inset", "ez");
 67        add("application/dsptype", "tsp");
 68        add("application/json", "json");
 69        add("application/epub+zip", "epub");
 70        add("application/gpx+xml", "gpx");
 71        add("application/hta", "hta");
 72        add("application/mac-binhex40", "hqx");
 73        add("application/mathematica", "nb");
 74        add("application/msaccess", "mdb");
 75        add("application/oda", "oda");
 76        add("application/ogg", "ogg");
 77        add("application/pdf", "pdf");
 78        add("application/pgp-keys", "key");
 79        add("application/pgp-signature", "pgp");
 80        add("application/pics-rules", "prf");
 81        add("application/pkix-cert", "cer");
 82        add("application/rar", "rar");
 83        add("application/rdf+xml", "rdf");
 84        add("application/rss+xml", "rss");
 85        add("application/zip", "zip");
 86        add("application/vnd.amazon.mobi8-ebook", "azw3");
 87        add("application/vnd.amazon.mobi8-ebook", "azw");
 88        add("application/vnd.amazon.mobi8-ebook", "kfx");
 89        add("application/vnd.android.package-archive", "apk");
 90        add("application/vnd.cinderella", "cdy");
 91        add(ExportBackupWorker.MIME_TYPE, "ceb");
 92        add("application/vnd.ms-pki.stl", "stl");
 93        add("application/vnd.oasis.opendocument.database", "odb");
 94        add("application/vnd.oasis.opendocument.formula", "odf");
 95        add("application/vnd.oasis.opendocument.graphics", "odg");
 96        add("application/vnd.oasis.opendocument.graphics-template", "otg");
 97        add("application/vnd.oasis.opendocument.image", "odi");
 98        add("application/vnd.oasis.opendocument.spreadsheet", "ods");
 99        add("application/vnd.oasis.opendocument.spreadsheet-template", "ots");
100        add("application/vnd.oasis.opendocument.text", "odt");
101        add("application/vnd.oasis.opendocument.text-master", "odm");
102        add("application/vnd.oasis.opendocument.text-template", "ott");
103        add("application/vnd.oasis.opendocument.text-web", "oth");
104        add("application/vnd.oasis.opendocument.presentation", "odp");
105        add("application/vnd.google-earth.kml+xml", "kml");
106        add("application/vnd.google-earth.kmz", "kmz");
107        add("application/msword", "doc");
108        add("application/msword", "dot");
109        add("application/vnd.openxmlformats-officedocument.wordprocessingml.document", "docx");
110        add("application/vnd.openxmlformats-officedocument.wordprocessingml.template", "dotx");
111        add("application/vnd.ms-excel", "xls");
112        add("application/vnd.ms-excel", "xlt");
113        add("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "xlsx");
114        add("application/vnd.openxmlformats-officedocument.spreadsheetml.template", "xltx");
115        add("application/vnd.ms-powerpoint", "ppt");
116        add("application/vnd.ms-powerpoint", "pot");
117        add("application/vnd.ms-powerpoint", "pps");
118        add("application/vnd.openxmlformats-officedocument.presentationml.presentation", "pptx");
119        add("application/vnd.openxmlformats-officedocument.presentationml.template", "potx");
120        add("application/vnd.openxmlformats-officedocument.presentationml.slideshow", "ppsx");
121        add("application/vnd.rim.cod", "cod");
122        add("application/vnd.smaf", "mmf");
123        add("application/vnd.stardivision.calc", "sdc");
124        add("application/vnd.stardivision.draw", "sda");
125        add("application/vnd.stardivision.impress", "sdd");
126        add("application/vnd.stardivision.impress", "sdp");
127        add("application/vnd.stardivision.math", "smf");
128        add("application/vnd.stardivision.writer", "sdw");
129        add("application/vnd.stardivision.writer", "vor");
130        add("application/vnd.stardivision.writer-global", "sgl");
131        add("application/vnd.sun.xml.calc", "sxc");
132        add("application/vnd.sun.xml.calc.template", "stc");
133        add("application/vnd.sun.xml.draw", "sxd");
134        add("application/vnd.sun.xml.draw.template", "std");
135        add("application/vnd.sun.xml.impress", "sxi");
136        add("application/vnd.sun.xml.impress.template", "sti");
137        add("application/vnd.sun.xml.math", "sxm");
138        add("application/vnd.sun.xml.writer", "sxw");
139        add("application/vnd.sun.xml.writer.global", "sxg");
140        add("application/vnd.sun.xml.writer.template", "stw");
141        add("application/vnd.visio", "vsd");
142        add("application/x-7z-compressed", "7z");
143        add("application/x-abiword", "abw");
144        add("application/x-apple-diskimage", "dmg");
145        add("application/x-bcpio", "bcpio");
146        add("application/x-bittorrent", "torrent");
147        add("application/x-cdf", "cdf");
148        add("application/x-cdlink", "vcd");
149        add("application/x-chess-pgn", "pgn");
150        add("application/x-cpio", "cpio");
151        add("application/x-debian-package", "deb");
152        add("application/x-debian-package", "udeb");
153        add("application/x-director", "dcr");
154        add("application/x-director", "dir");
155        add("application/x-director", "dxr");
156        add("application/x-dms", "dms");
157        add("application/x-doom", "wad");
158        add("application/x-dvi", "dvi");
159        add("application/x-font", "pfa");
160        add("application/x-font", "pfb");
161        add("application/x-font", "gsf");
162        add("application/x-font", "pcf");
163        add("application/x-font", "pcf.Z");
164        add("application/x-freemind", "mm");
165        // application/futuresplash isn't IANA, so application/x-futuresplash should come first.
166        add("application/x-futuresplash", "spl");
167        add("application/futuresplash", "spl");
168        add("application/x-gnumeric", "gnumeric");
169        add("application/x-go-sgf", "sgf");
170        add("application/x-graphing-calculator", "gcf");
171        add("application/x-gtar", "tgz");
172        add("application/x-gtar", "gtar");
173        add("application/x-gtar", "taz");
174        add("application/x-hdf", "hdf");
175        add("application/x-ica", "ica");
176        add("application/x-internet-signup", "ins");
177        add("application/x-internet-signup", "isp");
178        add("application/x-iphone", "iii");
179        add("application/x-iso9660-image", "iso");
180        add("application/x-jmol", "jmz");
181        add("application/x-kchart", "chrt");
182        add("application/x-killustrator", "kil");
183        add("application/x-koan", "skp");
184        add("application/x-koan", "skd");
185        add("application/x-koan", "skt");
186        add("application/x-koan", "skm");
187        add("application/x-kpresenter", "kpr");
188        add("application/x-kpresenter", "kpt");
189        add("application/x-kspread", "ksp");
190        add("application/x-kword", "kwd");
191        add("application/x-kword", "kwt");
192        add("application/x-latex", "latex");
193        add("application/x-lha", "lha");
194        add("application/x-lzh", "lzh");
195        add("application/x-lzx", "lzx");
196        add("application/x-maker", "frm");
197        add("application/x-maker", "maker");
198        add("application/x-maker", "frame");
199        add("application/x-maker", "fb");
200        add("application/x-maker", "book");
201        add("application/x-maker", "fbdoc");
202        add("application/x-mif", "mif");
203        add("application/x-mobipocket-ebook", "mobi");
204        add("application/x-ms-wmd", "wmd");
205        add("application/x-ms-wmz", "wmz");
206        add("application/x-msi", "msi");
207        add("application/x-ns-proxy-autoconfig", "pac");
208        add("application/x-nwc", "nwc");
209        add("application/x-object", "o");
210        add("application/x-oz-application", "oza");
211        add("application/x-pem-file", "pem");
212        add("application/x-pkcs12", "p12");
213        add("application/x-pkcs12", "pfx");
214        add("application/x-pkcs7-certreqresp", "p7r");
215        add("application/x-pkcs7-crl", "crl");
216        add("application/x-quicktimeplayer", "qtl");
217        add("application/x-shar", "shar");
218        add("application/x-shockwave-flash", "swf");
219        add("application/x-stuffit", "sit");
220        add("application/x-sv4cpio", "sv4cpio");
221        add("application/x-sv4crc", "sv4crc");
222        add("application/x-tar", "tar");
223        add("application/x-texinfo", "texinfo");
224        add("application/x-texinfo", "texi");
225        add("application/x-troff", "t");
226        add("application/x-troff", "roff");
227        add("application/x-troff-man", "man");
228        add("application/x-ustar", "ustar");
229        add("application/x-wais-source", "src");
230        add("application/x-wingz", "wz");
231        add("application/x-webarchive", "webarchive");
232        add("application/x-webarchive-xml", "webarchivexml");
233        add("application/x-x509-ca-cert", "crt");
234        add("application/x-x509-user-cert", "crt");
235        add("application/x-x509-server-cert", "crt");
236        add("application/x-xcf", "xcf");
237        add("application/x-xfig", "fig");
238        add("application/webxdc+zip", "xdc");
239        add("application/xhtml+xml", "xhtml");
240        add("video/3gpp", "3gpp");
241        add("video/3gpp", "3gp");
242        add("video/3gpp2", "3gpp2");
243        add("video/3gpp2", "3g2");
244        add("audio/3gpp", "3gpp");
245        add("audio/3gpp", "3gp");
246        add("audio/aac", "aac");
247        add("audio/aac-adts", "aac");
248        add("audio/amr", "amr");
249        add("audio/amr-wb", "awb");
250        add("audio/basic", "snd");
251        add("audio/flac", "flac");
252        add("application/x-flac", "flac");
253        add("audio/imelody", "imy");
254        add("audio/midi", "mid");
255        add("audio/midi", "midi");
256        add("audio/midi", "ota");
257        add("audio/midi", "kar");
258        add("audio/midi", "rtttl");
259        add("audio/midi", "xmf");
260        add("audio/mobile-xmf", "mxmf");
261        // add ".mp3" first so it will be the default for guessExtensionFromMimeType
262        add("audio/mpeg", "mp3");
263        add("audio/mpeg", "mpga");
264        add("audio/mpeg", "mpega");
265        add("audio/mpeg", "mp2");
266        add("audio/mp4", "m4a");
267        add("audio/x-m4b", "m4b");
268        add("audio/mpegurl", "m3u");
269        add("audio/ogg", "oga");
270        add("audio/ogg; codecs=opus", "opus"); // opus in ogg container
271        add("audio/opus", "opus"); // audio/opus for containerless opus
272        add("audio/prs.sid", "sid");
273        add("audio/x-aiff", "aif");
274        add("audio/x-aiff", "aiff");
275        add("audio/x-aiff", "aifc");
276        add("audio/x-gsm", "gsm");
277        add("audio/x-matroska", "mka");
278        add("audio/x-mpegurl", "m3u");
279        add("audio/x-ms-wma", "wma");
280        add("audio/x-ms-wax", "wax");
281        add("audio/x-pn-realaudio", "ra");
282        add("audio/x-pn-realaudio", "rm");
283        add("audio/x-pn-realaudio", "ram");
284        add("audio/x-realaudio", "ra");
285        add("audio/x-scpls", "pls");
286        add("audio/x-sd2", "sd2");
287        add("audio/x-wav", "wav");
288        // image/bmp isn't IANA, so image/x-ms-bmp should come first.
289        add("image/x-ms-bmp", "bmp");
290        add("image/bmp", "bmp");
291        add("image/gif", "gif");
292        // image/ico isn't IANA, so image/x-icon should come first.
293        add("image/x-icon", "ico");
294        add("image/ico", "cur");
295        add("image/ico", "ico");
296        add("image/ief", "ief");
297        add("image/heic", "heic");
298        add("image/heif", "heif");
299        add("image/avif", "avif");
300        // add ".jpg" first so it will be the default for guessExtensionFromMimeType
301        add("image/jpeg", "jpg");
302        add("image/jpeg", "jpeg");
303        add("image/jpeg", "jpe");
304        add("image/jpeg", "jfif");
305        add("image/jpeg", "jif");
306        add("image/pcx", "pcx");
307        add("image/png", "png");
308        add("image/svg+xml", "svg");
309        add("image/svg+xml", "svgz");
310        add("image/tiff", "tiff");
311        add("image/tiff", "tif");
312        add("image/vnd.djvu", "djvu");
313        add("image/vnd.djvu", "djv");
314        add("image/vnd.wap.wbmp", "wbmp");
315        add("image/webp", "webp");
316        add("image/x-cmu-raster", "ras");
317        add("image/x-coreldraw", "cdr");
318        add("image/x-coreldrawpattern", "pat");
319        add("image/x-coreldrawtemplate", "cdt");
320        add("image/x-corelphotopaint", "cpt");
321        add("image/x-jg", "art");
322        add("image/x-jng", "jng");
323        add("image/x-photoshop", "psd");
324        add("image/x-portable-anymap", "pnm");
325        add("image/x-portable-bitmap", "pbm");
326        add("image/x-portable-graymap", "pgm");
327        add("image/x-portable-pixmap", "ppm");
328        add("image/x-rgb", "rgb");
329        add("image/x-xbitmap", "xbm");
330        add("image/x-xpixmap", "xpm");
331        add("image/x-xwindowdump", "xwd");
332        add("message/rfc822", "eml");
333        add("message/rfc822", "mime");
334        add("model/iges", "igs");
335        add("model/iges", "iges");
336        add("model/mesh", "msh");
337        add("model/mesh", "mesh");
338        add("model/mesh", "silo");
339        add("text/calendar", "ics");
340        add("text/calendar", "icz");
341        add("text/comma-separated-values", "csv");
342        add("text/css", "css");
343        add("text/html", "htm");
344        add("text/html", "html");
345        add("text/h323", "323");
346        add("text/iuls", "uls");
347        add("text/javascript", "js");
348        add("text/mathml", "mml");
349        // add ".txt" first so it will be the default for guessExtensionFromMimeType
350        add("text/plain", "txt");
351        add("text/plain", "asc");
352        add("text/plain", "text");
353        add("text/plain", "diff");
354        add("text/plain", "po"); // reserve "pot" for vnd.ms-powerpoint
355        add("text/richtext", "rtx");
356        add("text/rtf", "rtf");
357        add("text/text", "phps");
358        add("text/tab-separated-values", "tsv");
359        add("text/xml", "xml");
360        add("text/x-bibtex", "bib");
361        add("text/x-boo", "boo");
362        add("text/x-c++hdr", "hpp");
363        add("text/x-c++hdr", "h++");
364        add("text/x-c++hdr", "hxx");
365        add("text/x-c++hdr", "hh");
366        add("text/x-c++src", "cpp");
367        add("text/x-c++src", "c++");
368        add("text/x-c++src", "cc");
369        add("text/x-c++src", "cxx");
370        add("text/x-chdr", "h");
371        add("text/x-component", "htc");
372        add("text/x-csh", "csh");
373        add("text/x-csrc", "c");
374        add("text/x-dsrc", "d");
375        add("text/x-haskell", "hs");
376        add("text/x-java", "java");
377        add("text/x-literate-haskell", "lhs");
378        add("text/x-moc", "moc");
379        add("text/x-pascal", "p");
380        add("text/x-pascal", "pas");
381        add("text/x-pcs-gcd", "gcd");
382        add("text/x-setext", "etx");
383        add("text/x-tcl", "tcl");
384        add("text/x-tex", "tex");
385        add("text/x-tex", "ltx");
386        add("text/x-tex", "sty");
387        add("text/x-tex", "cls");
388        add("text/x-vcalendar", "vcs");
389        add("text/x-vcard", "vcf");
390        add("video/avi", "avi");
391        add("video/dl", "dl");
392        add("video/dv", "dif");
393        add("video/dv", "dv");
394        add("video/fli", "fli");
395        add("video/m4v", "m4v");
396        add("video/mp2ts", "ts");
397        add("video/ogg", "ogv");
398        add("video/mpeg", "mpeg");
399        add("video/mpeg", "mpg");
400        add("video/mpeg", "mpe");
401        add("video/mp4", "mp4");
402        add("video/mpeg", "VOB");
403        add("video/quicktime", "qt");
404        add("video/quicktime", "mov");
405        add("video/vnd.mpegurl", "mxu");
406        add("video/webm", "webm");
407        add("video/x-la-asf", "lsf");
408        add("video/x-la-asf", "lsx");
409        add("video/x-matroska", "mkv");
410        add("video/x-mng", "mng");
411        add("video/x-ms-asf", "asf");
412        add("video/x-ms-asf", "asx");
413        add("video/x-ms-wm", "wm");
414        add("video/x-ms-wmv", "wmv");
415        add("video/x-ms-wmx", "wmx");
416        add("video/x-ms-wvx", "wvx");
417        add("video/x-sgi-movie", "movie");
418        add("video/x-webex", "wrf");
419        add("x-conference/x-cooltalk", "ice");
420        add("x-epoc/x-sisx-app", "sisx");
421        applyOverrides();
422    }
423
424    // mime types that are more reliant by path
425    private static final Collection<String> PATH_PRECEDENCE_MIME_TYPE =
426            Arrays.asList("audio/x-m4b");
427
428    private static void add(String mimeType, String extension) {
429        // If we have an existing x -> y mapping, we do not want to
430        // override it with another mapping x -> y2.
431        // If a mime type maps to several extensions
432        // the first extension added is considered the most popular
433        // so we do not want to overwrite it later.
434        if (!mimeTypeToExtensionMap.containsKey(mimeType)) {
435            mimeTypeToExtensionMap.put(mimeType, extension);
436        }
437        if (!extensionToMimeTypeMap.containsKey(extension)) {
438            extensionToMimeTypeMap.put(extension, mimeType);
439        }
440    }
441
442    private static InputStream getContentTypesPropertiesStream() {
443        // User override?
444        String userTable = System.getProperty("content.types.user.table");
445        if (userTable != null) {
446            File f = new File(userTable);
447            if (f.exists()) {
448                try {
449                    return new FileInputStream(f);
450                } catch (IOException ignored) {
451                }
452            }
453        }
454        // Standard location?
455        File f =
456                new File(
457                        System.getProperty("java.home"),
458                        "lib" + File.separator + "content-types.properties");
459        if (f.exists()) {
460            try {
461                return new FileInputStream(f);
462            } catch (IOException ignored) {
463            }
464        }
465        return null;
466    }
467
468    /**
469     * This isn't what the RI does. The RI doesn't have hard-coded defaults, so supplying your own
470     * "content.types.user.table" means you don't get any of the built-ins, and the built-ins come
471     * from "$JAVA_HOME/lib/content-types.properties".
472     */
473    private static void applyOverrides() {
474        // Get the appropriate InputStream to read overrides from, if any.
475        InputStream stream = getContentTypesPropertiesStream();
476        if (stream == null) {
477            return;
478        }
479        try {
480            try {
481                // Read the properties file...
482                Properties overrides = new Properties();
483                overrides.load(stream);
484                // And translate its mapping to ours...
485                for (Map.Entry<Object, Object> entry : overrides.entrySet()) {
486                    String extension = (String) entry.getKey();
487                    String mimeType = (String) entry.getValue();
488                    add(mimeType, extension);
489                }
490            } finally {
491                stream.close();
492            }
493        } catch (IOException ignored) {
494        }
495    }
496
497    private MimeUtils() {}
498
499    /**
500     * Returns true if the given MIME type has an entry in the map.
501     *
502     * @param mimeType A MIME type (i.e. text/plain)
503     * @return True iff there is a mimeType entry in the map.
504     */
505    public static boolean hasMimeType(String mimeType) {
506        if (mimeType == null || mimeType.isEmpty()) {
507            return false;
508        }
509        return mimeTypeToExtensionMap.containsKey(mimeType);
510    }
511
512    /**
513     * Returns the MIME type for the given extension.
514     *
515     * @param extension A file extension without the leading '.'
516     * @return The MIME type for the given extension or null iff there is none.
517     */
518    public static String guessMimeTypeFromExtension(String extension) {
519        if (extension == null || extension.isEmpty()) {
520            return null;
521        }
522        return extensionToMimeTypeMap.get(extension.toLowerCase());
523    }
524
525    /**
526     * Returns true if the given extension has a registered MIME type.
527     *
528     * @param extension A file extension without the leading '.'
529     * @return True iff there is an extension entry in the map.
530     */
531    public static boolean hasExtension(String extension) {
532        if (extension == null || extension.isEmpty()) {
533            return false;
534        }
535        return extensionToMimeTypeMap.containsKey(extension);
536    }
537
538    /**
539     * Returns the registered extension for the given MIME type. Note that some MIME types map to
540     * multiple extensions. This call will return the most 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(
553            final Context context, final Uri uri, final String mime) {
554        Log.d(Config.LOGTAG, "guessMimeTypeFromUriAndMime(" + uri + "," + mime + ")");
555        final String mimeFromUri = guessMimeTypeFromUri(context, uri);
556        Log.d(Config.LOGTAG, "mimeFromUri:" + mimeFromUri);
557        if (PATH_PRECEDENCE_MIME_TYPE.contains(mimeFromUri)) {
558            return mimeFromUri;
559        } else if (mime == null || mime.equals("application/octet-stream")) {
560            return mimeFromUri;
561        } else {
562            return mime;
563        }
564    }
565
566    public static String guessMimeTypeFromUri(final Context context, final Uri uri) {
567        if ("data".equals(uri.getScheme())) {
568            String[] parts = uri.getSchemeSpecificPart().split(",", 2);
569            String[] parts2 = parts[0].split(";", 2);
570            if (parts2.length > 0) return parts2[0];
571        }
572        final String mimeTypeContentResolver = guessFromContentResolver(context, uri);
573        final String mimeTypeFromQueryParameter = uri.isHierarchical() ? uri.getQueryParameter("mimeType") : null;
574        final String name = "content".equals(uri.getScheme()) ? getDisplayName(context, uri) : null;
575        final String mimeTypeFromName = Strings.isNullOrEmpty(name) ? null : guessFromPath(name);
576        final String path = uri.getPath();
577        final String mimeTypeFromPath = Strings.isNullOrEmpty(path) ? null : guessFromPath(path);
578        if (PATH_PRECEDENCE_MIME_TYPE.contains(mimeTypeFromName)) {
579            return mimeTypeFromName;
580        }
581        if (PATH_PRECEDENCE_MIME_TYPE.contains(mimeTypeFromPath)) {
582            return mimeTypeFromPath;
583        }
584        if (mimeTypeContentResolver != null
585                && !"application/octet-stream".equals(mimeTypeContentResolver)) {
586            return mimeTypeContentResolver;
587        }
588        if (mimeTypeFromName != null) {
589            return mimeTypeFromName;
590        }
591        if (mimeTypeFromQueryParameter != null) {
592            return mimeTypeFromQueryParameter;
593        }
594        return mimeTypeFromPath;
595    }
596
597    private static String guessFromContentResolver(final Context context, final Uri uri) {
598        try {
599            return context.getContentResolver().getType(uri);
600        } catch (final Throwable e) {
601            return null;
602        }
603    }
604
605    private static String getDisplayName(final Context context, final Uri uri) {
606        try (final Cursor cursor =
607                context.getContentResolver().query(uri, null, null, null, null)) {
608            if (cursor != null && cursor.moveToFirst()) {
609                final int index = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
610                if (index == -1) {
611                    return null;
612                }
613                return cursor.getString(index);
614            }
615        } catch (final Exception e) {
616            return null;
617        }
618        return null;
619    }
620
621    public static String guessFromPath(final String path) {
622        final int start = path.lastIndexOf('.') + 1;
623        if (start < path.length()) {
624            return MimeUtils.guessMimeTypeFromExtension(path.substring(start));
625        }
626        return null;
627    }
628
629    public static String extractRelevantExtension(final String path) {
630        return extractRelevantExtension(path, false);
631    }
632
633    public static String extractRelevantExtension(
634            final String path, final boolean ignoreCryptoExtension) {
635        if (Strings.isNullOrEmpty(path)) {
636            return null;
637        }
638
639        final String filenameQueryAnchor = path.substring(path.lastIndexOf('/') + 1);
640        final String filenameQuery = cutBefore(filenameQueryAnchor, '#');
641        final String filename = cutBefore(filenameQuery, '?');
642        final int dotPosition = filename.lastIndexOf('.');
643
644        if (dotPosition == -1) {
645            return null;
646        }
647        final String extension = filename.substring(dotPosition + 1);
648        // we want the real file extension, not the crypto one
649        if (ignoreCryptoExtension && Transferable.VALID_CRYPTO_EXTENSIONS.contains(extension)) {
650            return extractRelevantExtension(filename.substring(0, dotPosition));
651        } else {
652            return extension;
653        }
654    }
655
656    private static String cutBefore(final String input, final char c) {
657        final int position = input.indexOf(c);
658        if (position > 0) {
659            return input.substring(0, position);
660        } else {
661            return input;
662        }
663    }
664}