src/metabundlesaver.cpp

   1 // Jeff Mitchell <kde-dev@emailgoeshere.com>, (C) 2006
   2 // License: GNU General Public License V2
   3
   4
   5 #define DEBUG_PREFIX "MetaBundleSaver"
   6
   7 #include <stdlib.h>
   8 #include <unistd.h>
   9 #include <stdio.h>
  10 #include <time.h>
  11 #include <sys/time.h>
  12 #include <sys/types.h>
  13 #include <fcntl.h>
  14
  15 #include "amarok.h"
  16 #include "amarokconfig.h"
  17 #include "collectiondb.h"
  18 #include "debug.h"
  19 #include "metabundlesaver.h"
  20 #include "scancontroller.h"
  21 #include <kapplication.h>
  22 #include <kfilemetainfo.h>
  23 #include <kio/global.h>
  24 #include <kio/job.h>
  25 #include <kio/jobclasses.h>
  26 #include <kio/netaccess.h>
  27 #include <kcodecs.h>
  28 #include <kurl.h>
  29 #include <QFile> //decodePath()
  30 #include <QByteArray>
  31 #include <QString>
  32 #include <fileref.h>
  33
  34 #include "config-amarok.h"
  35
  36 #include "metabundle.h"
  37
  38 MetaBundleSaver::MetaBundleSaver( MetaBundle *bundle )
  39     : QObject()
  40     , m_bundle( bundle )
  41     , m_tempSavePath( QString() )
  42     , m_origRenamedSavePath( QString() )
  43     , m_tempSaveDigest( 0 )
  44     , m_saveFileref( 0 )
  45     , m_maxlen( 8192 )
  46     , m_cleanupNeeded( false )
  47
  48 {
  49     DEBUG_BLOCK
  50 }
  51
  52 MetaBundleSaver::~MetaBundleSaver()
  53 {
  54     DEBUG_BLOCK
  55     if( m_cleanupNeeded )
  56         cleanupSave();
  57 }
  58
  59 TagLib::FileRef *
  60 MetaBundleSaver::prepareToSave()
  61 {
  62     DEBUG_BLOCK
  63
  64     m_cleanupNeeded = true;
  65     KMD5 md5sum( 0, 0 );
  66     const KUrl origPath = m_bundle->url();
  67     char hostbuf[32];
  68     int hostname = gethostname( hostbuf, 32 );
  69     hostbuf[31] = '\0';
  70     if( hostname != 0 )
  71     {
  72         debug() << "Could not determine hostname!";
  73         return 0;
  74     }
  75     QString pid;
  76     QString randomString = m_bundle->getRandomString( 8, true );
  77     m_tempSavePath = origPath.path() + ".amaroktemp.host-" + QString( hostbuf ) +
  78                         ".pid-" + pid.setNum( getpid() ) + ".random-" + randomString + '.' + m_bundle->type();
  79     m_origRenamedSavePath = origPath.path() + ".amarokoriginal.host-" + QString( hostbuf ) +
  80                         ".pid-" + pid.setNum( getpid() ) + ".random-" + randomString + '.' + m_bundle->type();
  81
  82
  83     //The next long step is to copy the file over.  We can't use KIO because it's not thread save,
  84     //and std and QFile only have provisions for renaming and removing, so manual it is
  85     //doing it block-by-block results it not needing a huge amount of memory overhead
  86
  87     debug() << "Copying original file to copy and caluclating MD5";
  88
  89     if( QFile::exists( m_tempSavePath ) )
  90     {
  91         debug() << "Temp file already exists!";
  92         return 0;
  93     }
  94
  95     QFile orig( m_bundle->url().path() );
  96     QFile copy( m_tempSavePath );
  97
  98     if( !orig.open( QIODevice::Unbuffered | QIODevice::ReadOnly ) )
  99     {
 100         debug() << "Could not open original file!";
 101         return 0;
 102     }
 103
 104     //Do this separately so as not to create a zero-length file if you can't read from input
 105     if( !copy.open( QIODevice::Unbuffered | QIODevice::WriteOnly | QIODevice::Truncate ) )
 106     {
 107         debug() << "Could not create file copy";
 108         return 0;
 109     }
 110
 111     Q_LONG actualreadlen, actualwritelen;
 112
 113     while( ( actualreadlen = orig.read( m_databuf, m_maxlen ) ) > 0 )
 114     {
 115         md5sum.update( m_databuf, actualreadlen );
 116         if( ( actualwritelen = copy.write( m_databuf, actualreadlen ) ) != actualreadlen )
 117         {
 118             debug() << "Error during copying of original file data to copy!";
 119             return 0;
 120         }
 121     }
 122
 123     if( actualreadlen == -1 )
 124     {
 125         debug() << "Error during reading original file!";
 126         return 0;
 127     }
 128
 129     m_tempSaveDigest = md5sum.hexDigest();
 130
 131     //By this point, we have the following:
 132     //The original file is copied at path m_tempSavePath
 133     //We have generated what will be the filename to rename the original to in m_origRenamedSavePath
 134     //We have successfully copied the original file to the temp location
 135     //We've calculated the md5sum of the original file
 136
 137     debug() << "MD5 sum of temp file: " << m_tempSaveDigest.data();
 138
 139     //Now, we have a MD5 sum of the original file at the time of copying saved in m_tempSaveDigest
 140     //Create a fileref on the copied file, for modification
 141
 142     m_saveFileref = new TagLib::FileRef( QFile::encodeName( m_tempSavePath ), false );
 143
 144     if( m_saveFileref && !m_saveFileref->isNull() )
 145         return m_saveFileref;
 146
 147     debug() << "Error creating temp file's fileref!";
 148     return 0;
 149 }
 150
 151 bool
 152 MetaBundleSaver::doSave()
 153 {
 154     //TODO: much commenting needed.  For now this pretty much follows algorithm laid out in bug 131353,
 155     //but isn't useable since I need to find a good way to switch the file path with taglib, or a good way
 156     //to get all the metadata copied over.
 157
 158     DEBUG_BLOCK
 159     m_cleanupNeeded = true;
 160     bool revert = false;
 161
 162     QFile origRenamedFile( m_origRenamedSavePath );
 163     KMD5 md5sum( 0, 0 );
 164     Q_LONG actualreadlen;
 165
 166     int errcode;
 167
 168     QByteArray origRenamedDigest;
 169
 170     if( !m_saveFileref || m_tempSavePath.isEmpty() || m_tempSaveDigest.isEmpty() || m_origRenamedSavePath.isEmpty() )
 171     {
 172         debug() << "You must run prepareToSave() and it must return successfully before calling doSave()!";
 173         return false;
 174     }
 175
 176     debug() << "Saving tag changes to the temporary file...";
 177
 178     //We've made our changes to the fileref; save it first, then do the logic to move the correct file back
 179     if( !m_saveFileref->save() )
 180     {
 181         debug() << "Could not save the new file!";
 182         goto fail_remove_copy;
 183     }
 184
 185     debug() << "Renaming original file to temporary name " << m_origRenamedSavePath;
 186
 187     errcode = std::rename( QFile::encodeName( m_bundle->url().path() ).data(),
 188                                QFile::encodeName( m_origRenamedSavePath ).data() );
 189     if( errcode != 0 )
 190     {
 191         debug() << "Could not move original!";
 192         perror( "Could not move original!" );
 193         goto fail_remove_copy;
 194     }
 195
 196     revert = true;
 197
 198     debug() << "Calculating MD5 of " << m_origRenamedSavePath;
 199
 200     if( !origRenamedFile.open( QIODevice::Unbuffered | QIODevice::ReadOnly ) )
 201     {
 202         debug() << "Could not open temporary file!";
 203         goto fail_remove_copy;
 204     }
 205
 206     while( ( actualreadlen = origRenamedFile.read( m_databuf, m_maxlen ) ) > 0 )
 207         md5sum.update( m_databuf, actualreadlen );
 208
 209     if( actualreadlen == -1 )
 210     {
 211         debug() << "Error during checksumming temp file!";
 212         goto fail_remove_copy;
 213     }
 214
 215     origRenamedDigest = md5sum.hexDigest();
 216
 217     debug() << "md5sum of original file: " << origRenamedDigest.data();
 218
 219     if( origRenamedDigest != m_tempSaveDigest )
 220     {
 221         debug() << "Original checksum did not match current checksum!";
 222         goto fail_remove_copy;
 223     }
 224
 225     debug() << "Renaming temp file to original's filename";
 226
 227     errcode = std::rename( QFile::encodeName( m_tempSavePath ).data(),
 228                                 QFile::encodeName( m_bundle->url().path() ).data() );
 229     if( errcode != 0 )
 230     {
 231         debug() << "Could not rename newly-tagged file to original!";
 232         perror( "Could not rename newly-tagged file to original!" );
 233         goto fail_remove_copy;
 234     }
 235
 236     debug() << "Deleting original";
 237
 238     errcode = std::remove( QFile::encodeName( m_origRenamedSavePath ) );
 239     if( errcode != 0 )
 240     {
 241         debug() << "Could not delete the original file!";
 242         perror( "Could not delete the original file!" );
 243         return false;
 244     }
 245
 246     debug() << "Save done, returning true!";
 247
 248     return true;
 249
 250     fail_remove_copy:
 251
 252         debug() << "Deleting temporary file...";
 253         errcode = std::remove( QFile::encodeName( m_tempSavePath ).data() );
 254         if( errcode != 0 )
 255         {
 256             debug() << "Could not delete the temporary file!";
 257             perror( "Could not delete the temporary file!" );
 258         }
 259
 260         if( !revert )
 261             return false;
 262
 263         debug() << "Reverting original file to original filename!";
 264         errcode = std::rename( QFile::encodeName( m_origRenamedSavePath ).data(),
 265                                 QFile::encodeName( m_bundle->url().path() ).data() );
 266         if( errcode != 0 )
 267         {
 268             debug() << "Could not revert file to original filename!";
 269             perror( "Could not revert file to original filename!" );
 270         }
 271
 272         return false;
 273 }
 274
 275 bool
 276 MetaBundleSaver::cleanupSave()
 277 {
 278     DEBUG_BLOCK
 279
 280     bool dirty = false;
 281
 282     if( !m_tempSavePath.isEmpty() && QFile::exists( m_tempSavePath ) )
 283     {
 284         int errcode;
 285         errcode = std::remove( QFile::encodeName( m_tempSavePath ).data() );
 286         if( errcode != 0 )
 287         {
 288             dirty = true;
 289             debug() << "Could not delete the temporary file!";
 290         }
 291     }
 292
 293     m_tempSavePath.clear();
 294     m_origRenamedSavePath.clear();
 295     m_tempSaveDigest = QByteArray( 0 );
 296     if( m_saveFileref )
 297     {
 298         delete m_saveFileref;
 299         m_saveFileref = 0;
 300     }
 301
 302     m_cleanupNeeded = false;
 303     return !dirty;
 304 }
 305
 306 #include "metabundlesaver.moc"