@ -48,10 +48,10 @@ import static org.eclipse.jgit.lib.Constants.FALLBACK_TIMESTAMP_RESOLUTION;
import java.io.File ; import java.io.File ;
import java.io.IOException ; import java.io.IOException ;
import java.nio.file.attribute.BasicFileAttributes ; import java.nio.file.attribute.BasicFileAttributes ;
import java.text.DateFormat ;
import java.text.SimpleDateFormat ;
import java.time.Duration ; import java.time.Duration ;
import java.util.Date ; import java.time.Instant ;
import java.time.ZoneId ;
import java.time.format.DateTimeFormatter ;
import java.util.Locale ; import java.util.Locale ;
import java.util.Objects ; import java.util.Objects ;
import java.util.concurrent.TimeUnit ; import java.util.concurrent.TimeUnit ;
@ -87,8 +87,14 @@ public class FileSnapshot {
* / * /
public static final long UNKNOWN_SIZE = - 1 ; public static final long UNKNOWN_SIZE = - 1 ;
private static final Instant UNKNOWN_TIME = Instant . ofEpochMilli ( - 1 ) ;
private static final Object MISSING_FILEKEY = new Object ( ) ; private static final Object MISSING_FILEKEY = new Object ( ) ;
private static final DateTimeFormatter dateFmt = DateTimeFormatter
. ofPattern ( "yyyy-MM-dd HH:mm:ss.nnnnnnnnn" ) //$NON-NLS-1$
. withLocale ( Locale . getDefault ( ) ) . withZone ( ZoneId . systemDefault ( ) ) ;
/ * * / * *
* A FileSnapshot that is considered to always be modified . * A FileSnapshot that is considered to always be modified .
* < p > * < p >
@ -96,8 +102,8 @@ public class FileSnapshot {
* file , but only after { @link # isModified ( File ) } gets invoked . The returned * file , but only after { @link # isModified ( File ) } gets invoked . The returned
* snapshot contains only invalid status information . * snapshot contains only invalid status information .
* / * /
public static final FileSnapshot DIRTY = new FileSnapshot ( - 1 , - 1 , public static final FileSnapshot DIRTY = new FileSnapshot ( UNKNOWN_TIME ,
UNKNOWN_SIZE , Duration . ZERO , MISSING_FILEKEY ) ; UNKNOWN_TIME , UNKNOWN_ SIZE , Duration . ZERO , MISSING_FILEKEY ) ;
/ * * / * *
* A FileSnapshot that is clean if the file does not exist . * A FileSnapshot that is clean if the file does not exist .
@ -106,8 +112,8 @@ public class FileSnapshot {
* file to be clean . { @link # isModified ( File ) } will return false if the file * file to be clean . { @link # isModified ( File ) } will return false if the file
* path does not exist . * path does not exist .
* / * /
public static final FileSnapshot MISSING_FILE = new FileSnapshot ( 0 , 0 , 0 , public static final FileSnapshot MISSING_FILE = new FileSnapshot (
Duration . ZERO , MISSING_FILEKEY ) { Instant . EPOCH , Instant . EPOCH , 0 , Duration . ZERO , MISSING_FILEKEY ) {
@Override @Override
public boolean isModified ( File path ) { public boolean isModified ( File path ) {
return FS . DETECTED . exists ( path ) ; return FS . DETECTED . exists ( path ) ;
@ -163,18 +169,41 @@ public class FileSnapshot {
* @param modified * @param modified
* the last modification time of the file * the last modification time of the file
* @return the snapshot . * @return the snapshot .
* @deprecated use { @link # save ( Instant ) } instead .
* / * /
@Deprecated
public static FileSnapshot save ( long modified ) { public static FileSnapshot save ( long modified ) {
final long read = System . currentTimeMillis ( ) ; final Instant read = Instant . now ( ) ;
return new FileSnapshot ( read , Instant . ofEpochMilli ( modified ) ,
UNKNOWN_SIZE , Duration . ZERO , MISSING_FILEKEY ) ;
}
/ * *
* Record a snapshot for a file for which the last modification time is
* already known .
* < p >
* This method should be invoked before the file is accessed .
* < p >
* Note that this method cannot rely on measuring file timestamp resolution
* to avoid racy git issues caused by finite file timestamp resolution since
* it ' s unknown in which filesystem the file is located . Hence the worst
* case fallback for timestamp resolution is used .
*
* @param modified
* the last modification time of the file
* @return the snapshot .
* /
public static FileSnapshot save ( Instant modified ) {
final Instant read = Instant . now ( ) ;
return new FileSnapshot ( read , modified , UNKNOWN_SIZE , Duration . ZERO , return new FileSnapshot ( read , modified , UNKNOWN_SIZE , Duration . ZERO ,
MISSING_FILEKEY ) ; MISSING_FILEKEY ) ;
} }
/** Last observed modification time of the path. */ /** Last observed modification time of the path. */
private final long lastModified ; private final Instant lastModified ;
/** Last wall-clock time the path was read. */ /** Last wall-clock time the path was read. */
private volatile long lastRead ; private volatile Instant lastRead ;
/** True once {@link #lastRead} is far later than {@link #lastModified}. */ /** True once {@link #lastRead} is far later than {@link #lastModified}. */
private boolean cannotBeRacilyClean ; private boolean cannotBeRacilyClean ;
@ -222,7 +251,7 @@ public class FileSnapshot {
* / * /
protected FileSnapshot ( File file , boolean useConfig ) { protected FileSnapshot ( File file , boolean useConfig ) {
this . file = file ; this . file = file ;
this . lastRead = System . currentTimeMillis ( ) ; this . lastRead = Instant . now ( ) ;
this . fsTimestampResolution = useConfig this . fsTimestampResolution = useConfig
? FS . getFsTimerResolution ( file . toPath ( ) . getParent ( ) ) ? FS . getFsTimerResolution ( file . toPath ( ) . getParent ( ) )
: FALLBACK_TIMESTAMP_RESOLUTION ; : FALLBACK_TIMESTAMP_RESOLUTION ;
@ -230,18 +259,20 @@ public class FileSnapshot {
try { try {
fileAttributes = FS . DETECTED . fileAttributes ( file ) ; fileAttributes = FS . DETECTED . fileAttributes ( file ) ;
} catch ( IOException e ) { } catch ( IOException e ) {
this . lastModified = file . lastModified ( ) ; this . lastModified = Instant . ofEpochMilli ( file . lastModified ( ) ) ;
this . size = file . length ( ) ; this . size = file . length ( ) ;
this . fileKey = MISSING_FILEKEY ; this . fileKey = MISSING_FILEKEY ;
return ; return ;
} }
this . lastModified = fileAttributes . lastModifiedTime ( ) . toMillis ( ) ; this . lastModified = fileAttributes . lastModifiedTime ( ) . toInstant ( ) ;
this . size = fileAttributes . size ( ) ; this . size = fileAttributes . size ( ) ;
this . fileKey = getFileKey ( fileAttributes ) ; this . fileKey = getFileKey ( fileAttributes ) ;
LOG . debug ( "file={}, create new FileSnapshot: lastRead={} ms" //$NON-NLS-1$
if ( LOG . isDebugEnabled ( ) ) {
+ ", lastModified={} ms, size={}, fileKey={}" , //$NON-NLS-1$
LOG . debug ( "file={}, create new FileSnapshot: lastRead={}, lastModified={}, size={}, fileKey={}" , //$NON-NLS-1$
file , Long . valueOf ( lastRead ) , Long . valueOf ( lastModified ) , file , dateFmt . format ( lastRead ) ,
Long . valueOf ( size ) , fileKey ) ; dateFmt . format ( lastModified ) , Long . valueOf ( size ) ,
fileKey . toString ( ) ) ;
}
} }
private boolean sizeChanged ; private boolean sizeChanged ;
@ -252,7 +283,7 @@ public class FileSnapshot {
private boolean wasRacyClean ; private boolean wasRacyClean ;
private FileSnapshot ( long read , long modified , long size , private FileSnapshot ( Instant read , Instant modified , long size ,
@NonNull Duration fsTimestampResolution , @NonNull Object fileKey ) { @NonNull Duration fsTimestampResolution , @NonNull Object fileKey ) {
this . file = null ; this . file = null ;
this . lastRead = read ; this . lastRead = read ;
@ -266,8 +297,19 @@ public class FileSnapshot {
* Get time of last snapshot update * Get time of last snapshot update
* *
* @return time of last snapshot update * @return time of last snapshot update
* @deprecated use { @link # lastModifiedInstant ( ) } instead
* / * /
@Deprecated
public long lastModified ( ) { public long lastModified ( ) {
return lastModified . toEpochMilli ( ) ;
}
/ * *
* Get time of last snapshot update
*
* @return time of last snapshot update
* /
public Instant lastModifiedInstant ( ) {
return lastModified ; return lastModified ;
} }
@ -286,16 +328,16 @@ public class FileSnapshot {
* @return true if the path needs to be read again . * @return true if the path needs to be read again .
* / * /
public boolean isModified ( File path ) { public boolean isModified ( File path ) {
long currLastModified ; Instant currLastModified ;
long currSize ; long currSize ;
Object currFileKey ; Object currFileKey ;
try { try {
BasicFileAttributes fileAttributes = FS . DETECTED . fileAttributes ( path ) ; BasicFileAttributes fileAttributes = FS . DETECTED . fileAttributes ( path ) ;
currLastModified = fileAttributes . lastModifiedTime ( ) . toMillis ( ) ; currLastModified = fileAttributes . lastModifiedTime ( ) . toInstant ( ) ;
currSize = fileAttributes . size ( ) ; currSize = fileAttributes . size ( ) ;
currFileKey = getFileKey ( fileAttributes ) ; currFileKey = getFileKey ( fileAttributes ) ;
} catch ( IOException e ) { } catch ( IOException e ) {
currLastModified = path . lastModified ( ) ; currLastModified = Instant . ofEpochMilli ( path . lastModified ( ) ) ;
currSize = path . length ( ) ; currSize = path . length ( ) ;
currFileKey = MISSING_FILEKEY ; currFileKey = MISSING_FILEKEY ;
} }
@ -337,7 +379,7 @@ public class FileSnapshot {
* the other snapshot . * the other snapshot .
* / * /
public void setClean ( FileSnapshot other ) { public void setClean ( FileSnapshot other ) {
final long now = other . lastRead ; final Instant now = other . lastRead ;
if ( ! isRacyClean ( now ) ) { if ( ! isRacyClean ( now ) ) {
cannotBeRacilyClean = true ; cannotBeRacilyClean = true ;
} }
@ -351,7 +393,7 @@ public class FileSnapshot {
* if sleep was interrupted * if sleep was interrupted
* / * /
public void waitUntilNotRacy ( ) throws InterruptedException { public void waitUntilNotRacy ( ) throws InterruptedException {
while ( isRacyClean ( System . currentTimeMillis ( ) ) ) { while ( isRacyClean ( Instant . now ( ) ) ) {
TimeUnit . NANOSECONDS TimeUnit . NANOSECONDS
. sleep ( ( fsTimestampResolution . toNanos ( ) + 1 ) * 11 / 10 ) ; . sleep ( ( fsTimestampResolution . toNanos ( ) + 1 ) * 11 / 10 ) ;
} }
@ -366,7 +408,7 @@ public class FileSnapshot {
* / * /
public boolean equals ( FileSnapshot other ) { public boolean equals ( FileSnapshot other ) {
boolean sizeEq = size = = UNKNOWN_SIZE | | other . size = = UNKNOWN_SIZE | | size = = other . size ; boolean sizeEq = size = = UNKNOWN_SIZE | | other . size = = UNKNOWN_SIZE | | size = = other . size ;
return lastModified = = other . lastModified & & sizeEq return lastModified . equals ( other . lastModified ) & & sizeEq
& & Objects . equals ( fileKey , other . fileKey ) ; & & Objects . equals ( fileKey , other . fileKey ) ;
} }
@ -389,8 +431,7 @@ public class FileSnapshot {
/** {@inheritDoc} */ /** {@inheritDoc} */
@Override @Override
public int hashCode ( ) { public int hashCode ( ) {
return Objects . hash ( Long . valueOf ( lastModified ) , Long . valueOf ( size ) , return Objects . hash ( lastModified , Long . valueOf ( size ) , fileKey ) ;
fileKey ) ;
} }
/ * * / * *
@ -435,34 +476,37 @@ public class FileSnapshot {
if ( this = = MISSING_FILE ) { if ( this = = MISSING_FILE ) {
return "MISSING_FILE" ; return "MISSING_FILE" ;
} }
DateFormat f = new SimpleDateFormat ( "yyyy-MM-dd HH:mm:ss.SSS" , return "FileSnapshot[modified: " + dateFmt . format ( lastModified )
Locale . US ) ; + ", read: " + dateFmt . format ( lastRead ) + ", size:" + size
return "FileSnapshot[modified: " + f . format ( new Date ( lastModified ) )
+ ", read: " + f . format ( new Date ( lastRead ) ) + ", size:" + size
+ ", fileKey: " + fileKey + "]" ; + ", fileKey: " + fileKey + "]" ;
} }
private boolean isRacyClean ( long read ) { private boolean isRacyClean ( Instant read ) {
// add a 10% safety margin
// add a 10% safety margin
long racyNanos = ( fsTimestampResolution . toNanos ( ) + 1 ) * 11 / 10 ; long racyNanos = ( fsTimestampResolution . toNanos ( ) + 1 ) * 11 / 10 ;
long delta = ( read - lastModified ) * 1_000_000 ; long delta = Duration . between ( lastModified , read ) . toNanos ( ) ;
wasRacyClean = delta < = racyNanos ; wasRacyClean = delta < = racyNanos ;
LOG . debug ( "file={}, isRacyClean={}, read={} ms, lastModified={} ms," //$NON-NLS-1$
if ( LOG . isDebugEnabled ( ) ) {
+ " delta={} ns, racy<={} ns" , //$NON-NLS-1$
LOG . debug (
file , Boolean . valueOf ( wasRacyClean ) , Long . valueOf ( read ) , "file={}, isRacyClean={}, read={}, lastModified={}, delta={} ns, racy<={} ns" , //$NON-NLS-1$
Long . valueOf ( lastModified ) , Long . valueOf ( delta ) , file , Boolean . valueOf ( wasRacyClean ) , dateFmt . format ( read ) ,
dateFmt . format ( lastModified ) , Long . valueOf ( delta ) ,
Long . valueOf ( racyNanos ) ) ; Long . valueOf ( racyNanos ) ) ;
}
return wasRacyClean ; return wasRacyClean ;
} }
private boolean isModified ( long currLastModified ) { private boolean isModified ( Instant currLastModified ) {
// Any difference indicates the path was modified.
// Any difference indicates the path was modified.
lastModifiedChanged = lastModified ! = currLastModified ; lastModifiedChanged = ! lastModified . equals ( currLastModified ) ;
if ( lastModifiedChanged ) { if ( lastModifiedChanged ) {
LOG . debug ( "file={}, lastModified changed from {} to {}" , //$NON-NLS-1$
if ( LOG . isDebugEnabled ( ) ) {
file , Long . valueOf ( lastModified ) , LOG . debug (
Long . valueOf ( currLastModified ) ) ; "file={}, lastModified changed from {} to {}" , //$NON-NLS-1$
file , dateFmt . format ( lastModified ) ,
dateFmt . format ( currLastModified ) ) ;
}
return true ; return true ;
} }
Matthias Sohn
5 years ago