Class WalkRemoteObjectDatabase
- Direct Known Subclasses:
TransportAmazonS3.DatabaseS3
,TransportHttp.HttpObjectDB
,TransportSftp.SftpObjectDB
Implementations are responsible for resolving path names relative to the
objects/
subdirectory of a single remote Git repository or
naked object database and make the content available as a Java input stream
for reading during fetch. The actual object traversal logic to determine the
names of files to retrieve is handled through the generic, protocol
independent WalkFetchConnection
.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescription(package private) static final class
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Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescription(package private) abstract void
close()
Close any resources used by this connection.(package private) void
deleteFile
(String path) Delete a file from the object database.(package private) void
Delete a loose ref from the remote repository.(package private) void
deleteRefLog
(String name) Delete a reflog from the remote repository.(package private) abstract Collection
<WalkRemoteObjectDatabase> Obtain alternate connections to alternate object databases (if any).(package private) abstract Collection
<String> Obtain the list of available packs (if any).(package private) abstract URIish
getURI()
(package private) abstract WalkRemoteObjectDatabase.FileStream
Open a single file for reading.(package private) abstract WalkRemoteObjectDatabase
openAlternate
(String location) Create a new connection for a discovered alternate object database(package private) BufferedReader
openReader
(String path) Open a buffered reader around a file.(package private) Collection
<WalkRemoteObjectDatabase> readAlternates
(String listPath) Read a standard Git alternates file to discover other object databases.protected void
readPackedRefs
(Map<String, Ref> avail) Read a standard Git packed-refs file to discover known references.private void
readPackedRefsImpl
(Map<String, Ref> avail, BufferedReader br) (package private) void
Atomically write a remote file.(package private) OutputStream
writeFile
(String path, ProgressMonitor monitor, String monitorTask) Open a remote file for writing.(package private) void
writeInfoPacks
(Collection<String> packNames) Rebuild theINFO_PACKS
for dumb transport clients.(package private) void
Overwrite (or create) a loose ref in the remote repository.
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Field Details
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ROOT_DIR
- See Also:
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INFO_PACKS
- See Also:
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INFO_REFS
- See Also:
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Constructor Details
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WalkRemoteObjectDatabase
WalkRemoteObjectDatabase()
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Method Details
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getURI
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getPackNames
Obtain the list of available packs (if any).Pack names should be the file name in the packs directory, that is
pack-035760ab452d6eebd123add421f253ce7682355a.pack
. Index names should not be included in the returned collection.- Returns:
- list of pack names; null or empty list if none are available.
- Throws:
IOException
- The connection is unable to read the remote repository's list of available pack files.
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getAlternates
Obtain alternate connections to alternate object databases (if any).Alternates are typically read from the file
Constants.INFO_ALTERNATES
orConstants.INFO_HTTP_ALTERNATES
. The content of each line must be resolved by the implementation and a new database reference should be returned to represent the additional location.Alternates may reuse the same network connection handle, however the fetch connection will
close()
each created alternate.- Returns:
- list of additional object databases the caller could fetch from; null or empty list if none are configured.
- Throws:
IOException
- The connection is unable to read the remote repository's list of configured alternates.
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open
abstract WalkRemoteObjectDatabase.FileStream open(String path) throws FileNotFoundException, IOException Open a single file for reading.Implementors should make every attempt possible to ensure
FileNotFoundException
is used when the remote object does not exist. However when fetching over HTTP some misconfigured servers may generate a 200 OK status message (rather than a 404 Not Found) with an HTML formatted message explaining the requested resource does not exist. Callers such asWalkFetchConnection
are prepared to handle this by validating the content received, and assuming content that fails to match its hash is an incorrectly phrased FileNotFoundException.This method is recommended for already compressed files like loose objects and pack files. For text files, see
openReader(String)
.- Parameters:
path
- location of the file to read, relative to this objects directory (e.g.cb/95df6ab7ae9e57571511ef451cf33767c26dd2
orpack/pack-035760ab452d6eebd123add421f253ce7682355a.pack
).- Returns:
- a stream to read from the file. Never null.
- Throws:
FileNotFoundException
- the requested file does not exist at the given location.IOException
- The connection is unable to read the remote's file, and the failure occurred prior to being able to determine if the file exists, or after it was determined to exist but before the stream could be created.
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openAlternate
Create a new connection for a discovered alternate object databaseThis method is typically called by
readAlternates(String)
when subclasses us the generic alternate parsing logic for their implementation ofgetAlternates()
.- Parameters:
location
- the location of the new alternate, relative to the current object database.- Returns:
- a new database connection that can read from the specified alternate.
- Throws:
IOException
- The database connection cannot be established with the alternate, such as if the alternate location does not actually exist and the connection's constructor attempts to verify that.
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close
abstract void close()Close any resources used by this connection.If the remote repository is contacted by a network socket this method must close that network socket, disconnecting the two peers. If the remote repository is actually local (same system) this method must close any open file handles used to read the "remote" repository.
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deleteFile
Delete a file from the object database.Path may start with
../
to request deletion of a file that resides in the repository itself.When possible empty directories must be removed, up to but not including the current object database directory itself.
This method does not support deletion of directories.
- Parameters:
path
- name of the item to be removed, relative to the current object database.- Throws:
IOException
- deletion is not supported, or deletion failed.
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writeFile
Open a remote file for writing.Path may start with
../
to request writing of a file that resides in the repository itself.The requested path may or may not exist. If the path already exists as a file the file should be truncated and completely replaced.
This method creates any missing parent directories, if necessary.
- Parameters:
path
- name of the file to write, relative to the current object database.monitor
- (optional) progress monitor to post write completion to during the stream's close method.monitorTask
- (optional) task name to display during the close method.- Returns:
- stream to write into this file. Caller must close the stream to complete the write request. The stream is not buffered and each write may cause a network request/response so callers should buffer to smooth out small writes.
- Throws:
IOException
- writing is not supported, or attempting to write the file failed, possibly due to permissions or remote disk full, etc.
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writeFile
Atomically write a remote file.This method attempts to perform as atomic of an update as it can, reducing (or eliminating) the time that clients might be able to see partial file content. This method is not suitable for very large transfers as the complete content must be passed as an argument.
Path may start with
../
to request writing of a file that resides in the repository itself.The requested path may or may not exist. If the path already exists as a file the file should be truncated and completely replaced.
This method creates any missing parent directories, if necessary.
- Parameters:
path
- name of the file to write, relative to the current object database.data
- complete new content of the file.- Throws:
IOException
- writing is not supported, or attempting to write the file failed, possibly due to permissions or remote disk full, etc.
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deleteRef
Delete a loose ref from the remote repository.- Parameters:
name
- name of the ref within the ref space, for examplerefs/heads/pu
.- Throws:
IOException
- deletion is not supported, or deletion failed.
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deleteRefLog
Delete a reflog from the remote repository.- Parameters:
name
- name of the ref within the ref space, for examplerefs/heads/pu
.- Throws:
IOException
- deletion is not supported, or deletion failed.
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writeRef
Overwrite (or create) a loose ref in the remote repository.This method creates any missing parent directories, if necessary.
- Parameters:
name
- name of the ref within the ref space, for examplerefs/heads/pu
.value
- new value to store in this ref. Must not be null.- Throws:
IOException
- writing is not supported, or attempting to write the file failed, possibly due to permissions or remote disk full, etc.
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writeInfoPacks
Rebuild theINFO_PACKS
for dumb transport clients.This method rebuilds the contents of the
INFO_PACKS
file to match the passed list of pack names.- Parameters:
packNames
- names of available pack files, in the order they should appear in the file. Valid pack name strings are of the formpack-035760ab452d6eebd123add421f253ce7682355a.pack
.- Throws:
IOException
- writing is not supported, or attempting to write the file failed, possibly due to permissions or remote disk full, etc.
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openReader
Open a buffered reader around a file.This method is suitable for reading line-oriented resources like
info/packs
,info/refs
, and the alternates list.- Parameters:
path
- location of the file to read, relative to this objects directory (e.g.info/packs
).- Returns:
- a stream to read from the file. Never null.
- Throws:
FileNotFoundException
- the requested file does not exist at the given location.IOException
- The connection is unable to read the remote's file, and the failure occurred prior to being able to determine if the file exists, or after it was determined to exist but before the stream could be created.
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readAlternates
Read a standard Git alternates file to discover other object databases.This method is suitable for reading the standard formats of the alternates file, such as found in
objects/info/alternates
orobjects/info/http-alternates
within a Git repository.Alternates appear one per line, with paths expressed relative to this object database.
- Parameters:
listPath
- location of the alternate file to read, relative to this object database (e.g.info/alternates
).- Returns:
- the list of discovered alternates. Empty list if the file exists, but no entries were discovered.
- Throws:
FileNotFoundException
- the requested file does not exist at the given location.IOException
- The connection is unable to read the remote's file, and the failure occurred prior to being able to determine if the file exists, or after it was determined to exist but before the stream could be created.
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readPackedRefs
Read a standard Git packed-refs file to discover known references.- Parameters:
avail
- return collection of references. Any existing entries will be replaced if they are found in the packed-refs file.- Throws:
TransportException
- an error occurred reading from the packed refs file.
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readPackedRefsImpl
- Throws:
IOException
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