@@ -58,11 +58,17 @@ final class MultiDexExtractor {
5858 private static final String EXTRACTED_SUFFIX = ".zip" ;
5959 private static final int MAX_EXTRACT_ATTEMPTS = 3 ;
6060
61- private static final int BUFFER_SIZE = 0x4000 ;
62-
6361 private static final String PREFS_FILE = "multidex.version" ;
64- private static final String KEY_NUM_DEX_FILES = "num_dex" ;
65- private static final String KEY_PREFIX_DEX_CRC = "crc" ;
62+ private static final String KEY_TIME_STAMP = "timestamp" ;
63+ private static final String KEY_CRC = "crc" ;
64+ private static final String KEY_DEX_NUMBER = "dex.number" ;
65+
66+ /**
67+ * Size of reading buffers.
68+ */
69+ private static final int BUFFER_SIZE = 0x4000 ;
70+ /* Keep value away from 0 because it is a too probable time stamp value */
71+ private static final long NO_VALUE = -1L ;
6672
6773 /**
6874 * Extracts application secondary dexes into files in the application data
@@ -75,8 +81,87 @@ final class MultiDexExtractor {
7581 */
7682 static List <File > load (Context context , ApplicationInfo applicationInfo , File dexDir ,
7783 boolean forceReload ) throws IOException {
78- Log .i (TAG , "load(" + applicationInfo .sourceDir + ", forceReload= " + forceReload + ")" );
84+ Log .i (TAG , "MultiDexExtractor. load(" + applicationInfo .sourceDir + ", " + forceReload + ")" );
7985 final File sourceApk = new File (applicationInfo .sourceDir );
86+
87+ File archive = new File (applicationInfo .sourceDir );
88+ long currentCrc = getZipCrc (archive );
89+
90+ List <File > files ;
91+ if (!forceReload && !isModified (context , archive , currentCrc )) {
92+ try {
93+ files = loadExistingExtractions (context , sourceApk , dexDir );
94+ } catch (IOException ioe ) {
95+ Log .w (TAG , "Failed to reload existing extracted secondary dex files,"
96+ + " falling back to fresh extraction" , ioe );
97+ files = performExtractions (sourceApk , dexDir );
98+ putStoredApkInfo (context , getTimeStamp (sourceApk ), currentCrc , files .size () + 1 );
99+
100+ }
101+ } else {
102+ Log .i (TAG , "Detected that extraction must be performed." );
103+ files = performExtractions (sourceApk , dexDir );
104+ putStoredApkInfo (context , getTimeStamp (sourceApk ), currentCrc , files .size () + 1 );
105+ }
106+
107+ Log .i (TAG , "load found " + files .size () + " secondary dex files" );
108+ return files ;
109+ }
110+
111+ private static List <File > loadExistingExtractions (Context context , File sourceApk , File dexDir )
112+ throws IOException {
113+ Log .i (TAG , "loading existing secondary dex files" );
114+
115+ final String extractedFilePrefix = sourceApk .getName () + EXTRACTED_NAME_EXT ;
116+ int totalDexNumber = getMultiDexPreferences (context ).getInt (KEY_DEX_NUMBER , 1 );
117+ final List <File > files = new ArrayList <File >(totalDexNumber );
118+
119+ for (int secondaryNumber = 2 ; secondaryNumber <= totalDexNumber ; secondaryNumber ++) {
120+ String fileName = extractedFilePrefix + secondaryNumber + EXTRACTED_SUFFIX ;
121+ File extractedFile = new File (dexDir , fileName );
122+ if (extractedFile .isFile ()) {
123+ files .add (extractedFile );
124+ if (!verifyZipFile (extractedFile )) {
125+ Log .i (TAG , "Invalid zip file: " + extractedFile );
126+ throw new IOException ("Invalid ZIP file." );
127+ }
128+ } else {
129+ throw new IOException ("Missing extracted secondary dex file '" +
130+ extractedFile .getPath () + "'" );
131+ }
132+ }
133+
134+ return files ;
135+ }
136+
137+ private static boolean isModified (Context context , File archive , long currentCrc ) {
138+ SharedPreferences prefs = getMultiDexPreferences (context );
139+ return (prefs .getLong (KEY_TIME_STAMP , NO_VALUE ) != getTimeStamp (archive ))
140+ || (prefs .getLong (KEY_CRC , NO_VALUE ) != currentCrc );
141+ }
142+
143+ private static long getTimeStamp (File archive ) {
144+ long timeStamp = archive .lastModified ();
145+ if (timeStamp == NO_VALUE ) {
146+ // never return NO_VALUE
147+ timeStamp --;
148+ }
149+ return timeStamp ;
150+ }
151+
152+
153+ private static long getZipCrc (File archive ) throws IOException {
154+ long computedValue = ZipUtil .getZipCrc (archive );
155+ if (computedValue == NO_VALUE ) {
156+ // never return NO_VALUE
157+ computedValue --;
158+ }
159+ return computedValue ;
160+ }
161+
162+ private static List <File > performExtractions (File sourceApk , File dexDir )
163+ throws IOException {
164+
80165 final String extractedFilePrefix = sourceApk .getName () + EXTRACTED_NAME_EXT ;
81166
82167 // Ensure that whatever deletions happen in prepareDexDir only happen if the zip that
@@ -85,15 +170,9 @@ static List<File> load(Context context, ApplicationInfo applicationInfo, File de
85170 // while another had created it.
86171 prepareDexDir (dexDir , extractedFilePrefix );
87172
88- final List <File > files = new ArrayList <File >();
89- final ZipFile apk = new ZipFile (applicationInfo .sourceDir );
173+ List <File > files = new ArrayList <File >();
90174
91- // If the CRC of any of the dex files is different than what we have stored or the number of
92- // dex files are different, then force reload everything.
93- ArrayList <Long > dexCrcs = getAllDexCrcs (apk );
94- if (isAnyDexCrcDifferent (context , dexCrcs )) {
95- forceReload = true ;
96- }
175+ final ZipFile apk = new ZipFile (sourceApk );
97176 try {
98177
99178 int secondaryNumber = 2 ;
@@ -104,41 +183,36 @@ static List<File> load(Context context, ApplicationInfo applicationInfo, File de
104183 File extractedFile = new File (dexDir , fileName );
105184 files .add (extractedFile );
106185
107- Log .i (TAG , "Need extracted file " + extractedFile );
108- if (forceReload || !extractedFile .isFile ()) {
109- Log .i (TAG , "Extraction is needed for file " + extractedFile );
110- int numAttempts = 0 ;
111- boolean isExtractionSuccessful = false ;
112- while (numAttempts < MAX_EXTRACT_ATTEMPTS && !isExtractionSuccessful ) {
113- numAttempts ++;
114-
115- // Create a zip file (extractedFile) containing only the secondary dex file
116- // (dexFile) from the apk.
117- extract (apk , dexFile , extractedFile , extractedFilePrefix );
118-
119- // Verify that the extracted file is indeed a zip file.
120- isExtractionSuccessful = verifyZipFile (extractedFile );
121-
122- // Log the sha1 of the extracted zip file
123- Log .i (TAG , "Extraction " + (isExtractionSuccessful ? "success" : "failed" ) +
124- " - length " + extractedFile .getAbsolutePath () + ": " +
125- extractedFile .length ());
126- if (!isExtractionSuccessful ) {
127- // Delete the extracted file
128- extractedFile .delete ();
186+ Log .i (TAG , "Extraction is needed for file " + extractedFile );
187+ int numAttempts = 0 ;
188+ boolean isExtractionSuccessful = false ;
189+ while (numAttempts < MAX_EXTRACT_ATTEMPTS && !isExtractionSuccessful ) {
190+ numAttempts ++;
191+
192+ // Create a zip file (extractedFile) containing only the secondary dex file
193+ // (dexFile) from the apk.
194+ extract (apk , dexFile , extractedFile , extractedFilePrefix );
195+
196+ // Verify that the extracted file is indeed a zip file.
197+ isExtractionSuccessful = verifyZipFile (extractedFile );
198+
199+ // Log the sha1 of the extracted zip file
200+ Log .i (TAG , "Extraction " + (isExtractionSuccessful ? "success" : "failed" ) +
201+ " - length " + extractedFile .getAbsolutePath () + ": " +
202+ extractedFile .length ());
203+ if (!isExtractionSuccessful ) {
204+ // Delete the extracted file
205+ extractedFile .delete ();
206+ if (extractedFile .exists ()) {
207+ Log .w (TAG , "Failed to delete corrupted secondary dex '" +
208+ extractedFile .getPath () + "'" );
129209 }
130210 }
131- if (isExtractionSuccessful ) {
132- // Write the dex crc's into the shared preferences
133- putStoredDexCrcs (context , dexCrcs );
134- } else {
135- throw new IOException ("Could not create zip file " +
136- extractedFile .getAbsolutePath () + " for secondary dex (" +
137- secondaryNumber + ")" );
138- }
139- } else {
140- Log .i (TAG , "No extraction needed for " + extractedFile + " of size " +
141- extractedFile .length ());
211+ }
212+ if (!isExtractionSuccessful ) {
213+ throw new IOException ("Could not create zip file " +
214+ extractedFile .getAbsolutePath () + " for secondary dex (" +
215+ secondaryNumber + ")" );
142216 }
143217 secondaryNumber ++;
144218 dexFile = apk .getEntry (DEX_PREFIX + secondaryNumber + DEX_SUFFIX );
@@ -154,69 +228,17 @@ static List<File> load(Context context, ApplicationInfo applicationInfo, File de
154228 return files ;
155229 }
156230
157- /**
158- * Iterate through the expected dex files, classes.dex, classes2.dex, classes3.dex, etc. and
159- * return the CRC of each zip entry in a list.
160- */
161- private static ArrayList <Long > getAllDexCrcs (ZipFile apk ) {
162- ArrayList <Long > dexCrcs = new ArrayList <Long >();
163-
164- // Add the first one
165- dexCrcs .add (apk .getEntry (DEX_PREFIX + DEX_SUFFIX ).getCrc ());
166-
167- // Get the number of dex files in the apk.
168- int secondaryNumber = 2 ;
169- while (true ) {
170- ZipEntry dexEntry = apk .getEntry (DEX_PREFIX + secondaryNumber + DEX_SUFFIX );
171- if (dexEntry == null ) {
172- break ;
173- }
174-
175- dexCrcs .add (dexEntry .getCrc ());
176- secondaryNumber ++;
177- }
178- return dexCrcs ;
179- }
180-
181- /**
182- * Returns true if the number of dex files is different than what is stored in the shared
183- * preferences file or if any dex CRC value is different.
184- */
185- private static boolean isAnyDexCrcDifferent (Context context , ArrayList <Long > dexCrcs ) {
186- final ArrayList <Long > storedDexCrcs = getStoredDexCrcs (context );
187-
188- if (dexCrcs .size () != storedDexCrcs .size ()) {
189- return true ;
190- }
191-
192- // We know the length of storedDexCrcs and dexCrcs are the same.
193- for (int i = 0 ; i < storedDexCrcs .size (); i ++) {
194- if (storedDexCrcs .get (i ).longValue () != dexCrcs .get (i ).longValue ()) {
195- return true ;
196- }
197- }
198-
199- // All the same
200- return false ;
201- }
202-
203- private static ArrayList <Long > getStoredDexCrcs (Context context ) {
204- SharedPreferences prefs = getMultiDexPreferences (context );
205- int numDexFiles = prefs .getInt (KEY_NUM_DEX_FILES , 0 );
206- ArrayList <Long > dexCrcs = new ArrayList <Long >(numDexFiles );
207- for (int i = 0 ; i < numDexFiles ; i ++) {
208- dexCrcs .add (prefs .getLong (makeDexCrcKey (i ), 0 ));
209- }
210- return dexCrcs ;
211- }
212-
213- private static void putStoredDexCrcs (Context context , ArrayList <Long > dexCrcs ) {
231+ private static void putStoredApkInfo (Context context , long timeStamp , long crc ,
232+ int totalDexNumber ) {
214233 SharedPreferences prefs = getMultiDexPreferences (context );
215234 SharedPreferences .Editor edit = prefs .edit ();
216- edit .putInt (KEY_NUM_DEX_FILES , dexCrcs .size ());
217- for (int i = 0 ; i < dexCrcs .size (); i ++) {
218- edit .putLong (makeDexCrcKey (i ), dexCrcs .get (i ));
219- }
235+ edit .putLong (KEY_TIME_STAMP , timeStamp );
236+ edit .putLong (KEY_CRC , crc );
237+ /* SharedPreferences.Editor doc says that apply() and commit() "atomically performs the
238+ * requested modifications" it should be OK to rely on saving the dex files number (getting
239+ * old number value would go along with old crc and time stamp).
240+ */
241+ edit .putInt (KEY_DEX_NUMBER , totalDexNumber );
220242 apply (edit );
221243 }
222244
@@ -227,10 +249,6 @@ private static SharedPreferences getMultiDexPreferences(Context context) {
227249 : Context .MODE_PRIVATE | Context .MODE_MULTI_PROCESS );
228250 }
229251
230- private static String makeDexCrcKey (int i ) {
231- return KEY_PREFIX_DEX_CRC + Integer .toString (i );
232- }
233-
234252 /**
235253 * This removes any files that do not have the correct prefix.
236254 */
@@ -338,7 +356,7 @@ private static void closeQuietly(Closeable closeable) {
338356 private static Method sApplyMethod ; // final
339357 static {
340358 try {
341- Class cls = SharedPreferences .Editor .class ;
359+ Class <?> cls = SharedPreferences .Editor .class ;
342360 sApplyMethod = cls .getMethod ("apply" );
343361 } catch (NoSuchMethodException unused ) {
344362 sApplyMethod = null ;
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