* A reference database stores a mapping of reference names to * {@link org.eclipse.jgit.lib.ObjectId}. Every * {@link org.eclipse.jgit.lib.Repository} has a single reference database, * mapping names to the tips of the object graph contained by the * {@link org.eclipse.jgit.lib.ObjectDatabase}. */ public abstract class RefDatabase { /** * Order of prefixes to search when using non-absolute references. *
* {@link #findRef(String)} takes this search space into consideration when * locating a reference by name. The first entry in the path is always * {@code ""}, ensuring that absolute references are resolved without * further mangling. */ protected static final String[] SEARCH_PATH = { "", //$NON-NLS-1$ Constants.R_REFS, // Constants.R_TAGS, // Constants.R_HEADS, // Constants.R_REMOTES // }; /** * Maximum number of times a {@link SymbolicRef} can be traversed. *
* If the reference is nested deeper than this depth, the implementation * should either fail, or at least claim the reference does not exist. * * @since 4.2 */ public static final int MAX_SYMBOLIC_REF_DEPTH = 5; /** * Magic value for {@link #getRefsByPrefix(String)} to return all * references. */ public static final String ALL = "";//$NON-NLS-1$ /** * The names of additional refs * * @since 6.5 */ protected static final String[] additionalRefsNames = new String[] { Constants.MERGE_HEAD, Constants.FETCH_HEAD, Constants.ORIG_HEAD, Constants.CHERRY_PICK_HEAD, Constants.REVERT_HEAD }; /** * Initialize a new reference database at this location. * * @throws java.io.IOException * the database could not be created. */ public abstract void create() throws IOException; /** * Close any resources held by this database. */ public abstract void close(); /** * With versioning, each reference has a version number that increases on * update. See {@link Ref#getUpdateIndex()}. * * @implSpec This method returns false by default. Implementations * supporting versioning must override it to return true. * @return true if the implementation assigns update indices to references. * @since 5.3 */ public boolean hasVersioning() { return false; } /** * Determine if a proposed reference name overlaps with an existing one. *
* Reference names use '/' as a component separator, and may be stored in a * hierarchical storage such as a directory on the local filesystem. *
* If the reference "refs/heads/foo" exists then "refs/heads/foo/bar" must * not exist, as a reference cannot have a value and also be a container for * other references at the same time. *
* If the reference "refs/heads/foo/bar" exists than the reference
* "refs/heads/foo" cannot exist, for the same reason.
*
* @param name
* proposed name.
* @return true if the name overlaps with an existing reference; false if
* using this name right now would be safe.
* @throws java.io.IOException
* the database could not be read to check for conflicts.
* @see #getConflictingNames(String)
*/
public abstract boolean isNameConflicting(String name) throws IOException;
/**
* Determine if a proposed reference cannot coexist with existing ones. If
* the passed name already exists, it's not considered a conflict.
*
* @param name
* proposed name to check for conflicts against
* @return a collection of full names of existing refs which would conflict
* with the passed ref name; empty collection when there are no
* conflicts
* @throws java.io.IOException
* @since 2.3
* @see #isNameConflicting(String)
*/
@NonNull
public Collection
* The default implementation performs a sequential update of each command.
*
* @return a new batch update object.
*/
@NonNull
public BatchRefUpdate newBatchUpdate() {
return new BatchRefUpdate(this);
}
/**
* Whether the database is capable of performing batch updates as atomic
* transactions.
*
* If true, by default {@link org.eclipse.jgit.lib.BatchRefUpdate} instances
* will perform updates atomically, meaning either all updates will succeed,
* or all updates will fail. It is still possible to turn off this behavior
* on a per-batch basis by calling {@code update.setAtomic(false)}.
*
* If false, {@link org.eclipse.jgit.lib.BatchRefUpdate} instances will
* never perform updates atomically, and calling
* {@code update.setAtomic(true)} will cause the entire batch to fail with
* {@code REJECTED_OTHER_REASON}.
*
* This definition of atomicity is stronger than what is provided by
* {@link org.eclipse.jgit.transport.ReceivePack}. {@code ReceivePack} will
* attempt to reject all commands if it knows in advance some commands may
* fail, even if the storage layer does not support atomic transactions.
* Here, atomicity applies even in the case of unforeseeable errors.
*
* @return whether transactions are atomic by default.
* @since 3.6
*/
public boolean performsAtomicTransactions() {
return false;
}
/**
* Compatibility synonym for {@link #findRef(String)}.
*
* @param name
* the name of the reference. May be a short name which must be
* searched for using the standard {@link #SEARCH_PATH}.
* @return the reference (if it exists); else {@code null}.
* @throws IOException
* the reference space cannot be accessed.
* @deprecated Use {@link #findRef(String)} instead.
*/
@Deprecated
@Nullable
public final Ref getRef(String name) throws IOException {
return findRef(name);
}
/**
* Read a single reference.
*
* Aside from taking advantage of {@link #SEARCH_PATH}, this method may be
* able to more quickly resolve a single reference name than obtaining the
* complete namespace by {@code getRefs(ALL).get(name)}.
*
* To read a specific reference without using @{link #SEARCH_PATH}, see
* {@link #exactRef(String)}.
*
* @param name
* the name of the reference. May be a short name which must be
* searched for using the standard {@link #SEARCH_PATH}.
* @return the reference (if it exists); else {@code null}.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 5.3
*/
@Nullable
public final Ref findRef(String name) throws IOException {
String[] names = new String[SEARCH_PATH.length];
for (int i = 0; i < SEARCH_PATH.length; i++) {
names[i] = SEARCH_PATH[i] + name;
}
return firstExactRef(names);
}
/**
* Read a single reference.
*
* Unlike {@link #findRef}, this method expects an unshortened reference
* name and does not search using the standard {@link #SEARCH_PATH}.
*
* @param name
* the unabbreviated name of the reference.
* @return the reference (if it exists); else {@code null}.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 4.1
*/
@Nullable
public abstract Ref exactRef(String name) throws IOException;
/**
* Read the specified references.
*
* This method expects a list of unshortened reference names and returns
* a map from reference names to refs. Any named references that do not
* exist will not be included in the returned map.
*
* @param refs
* the unabbreviated names of references to look up.
* @return modifiable map describing any refs that exist among the ref
* ref names supplied. The map can be an unsorted map.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 4.1
*/
@NonNull
public Map
* This method expects a list of unshortened reference names and returns
* the first that exists.
*
* @param refs
* the unabbreviated names of references to look up.
* @return the first named reference that exists (if any); else {@code null}.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 4.1
*/
@Nullable
public Ref firstExactRef(String... refs) throws IOException {
for (String name : refs) {
Ref ref = exactRef(name);
if (ref != null) {
return ref;
}
}
return null;
}
/**
* Returns all refs.
*
* This includes {@code HEAD}, branches under {@code ref/heads/}, tags under
* {@code refs/tags/}, etc. It does not include pseudo-refs like
* {@code FETCH_HEAD}; for those, see {@link #getAdditionalRefs}.
*
* Symbolic references to a non-existent ref (for example, {@code HEAD}
* pointing to a branch yet to be born) are not included.
*
* Callers interested in only a portion of the ref hierarchy can call
* {@link #getRefsByPrefix} instead.
*
* @return immutable list of all refs.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 5.0
*/
@NonNull
public List getRefs() throws IOException {
return getRefsByPrefix(ALL);
}
/**
* Get a section of the reference namespace.
*
* @param prefix
* prefix to search the namespace with; must end with {@code /}.
* If the empty string ({@link #ALL}), obtain a complete snapshot
* of all references.
* @return modifiable map that is a complete snapshot of the current
* reference namespace, with {@code prefix} removed from the start
* of each key. The map can be an unsorted map.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @deprecated use {@link #getRefsByPrefix} instead
*/
@NonNull
@Deprecated
public abstract Map
* The default implementation uses {@link #getRefs(String)}. Implementors of
* {@link RefDatabase} should override this method directly if a better
* implementation is possible.
*
* @param prefix
* string that names of refs should start with; may be empty (to
* return all refs).
* @return immutable list of refs whose names start with {@code prefix}.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 5.0
*/
@NonNull
public List getRefsByPrefix(String prefix) throws IOException {
Map
* The default implementation is not efficient. Implementors of
* {@link RefDatabase} should override this method directly if a better
* implementation is possible.
*
* @param include
* string that names of refs should start with; may be empty.
* @param excludes
* strings that names of refs can't start with; may be empty.
* @return immutable list of refs whose names start with {@code prefix} and
* none of the strings in {@code exclude}.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 5.11
*/
@NonNull
public List getRefsByPrefixWithExclusions(String include, Set
* The default implementation uses {@link #getRefsByPrefix(String)}.
* Implementors of {@link RefDatabase} should override this method directly
* if a better implementation is possible.
*
* @param prefixes
* strings that names of refs should start with.
* @return immutable list of refs whose names start with one of
* {@code prefixes}. Refs can be unsorted and may contain duplicates
* if the prefixes overlap.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 5.2
*/
@NonNull
public List getRefsByPrefix(String... prefixes) throws IOException {
List result = new ArrayList<>();
for (String prefix : prefixes) {
result.addAll(getRefsByPrefix(prefix));
}
return Collections.unmodifiableList(result);
}
/**
* Returns all refs that resolve directly to the given {@link ObjectId}.
* Includes peeled {@link ObjectId}s. This is the inverse lookup of
* {@link #exactRef(String...)}.
*
*
* The default implementation uses a linear scan. Implementors of
* {@link RefDatabase} should override this method directly if a better
* implementation is possible.
*
* @param id
* {@link ObjectId} to resolve
* @return a {@link Set} of {@link Ref}s whose tips point to the provided
* id.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 5.4
*/
@NonNull
public Set getTipsWithSha1(ObjectId id) throws IOException {
return getRefs().stream().filter(r -> id.equals(r.getObjectId())
|| id.equals(r.getPeeledObjectId())).collect(toSet());
}
/**
* If the ref database does not support fast inverse queries, it may be
* advantageous to build a complete SHA1 to ref map in advance for multiple
* uses. To let applications decide on this decision, this function
* indicates whether the inverse map is available.
*
* @return whether this RefDatabase supports fast inverse ref queries.
* @throws IOException
* on I/O problems.
* @since 5.6
*/
public boolean hasFastTipsWithSha1() throws IOException {
return false;
}
/**
* Check if any refs exist in the ref database.
*
* This uses the same definition of refs as {@link #getRefs()}. In
* particular, returns {@code false} in a new repository with no refs under
* {@code refs/} and {@code HEAD} pointing to a branch yet to be born, and
* returns {@code true} in a repository with no refs under {@code refs/} and
* a detached {@code HEAD} pointing to history.
*
* @return true if the database has refs.
* @throws java.io.IOException
* the reference space cannot be accessed.
* @since 5.0
*/
public boolean hasRefs() throws IOException {
return !getRefs().isEmpty();
}
/**
* Get the additional reference-like entities from the repository.
*
* The result list includes non-ref items such as MERGE_HEAD and
* FETCH_RESULT cast to be refs. The names of these refs are not returned by
*
* If the reference cannot be peeled (as it does not refer to an annotated
* tag) the peeled id stays null, but
* {@link org.eclipse.jgit.lib.Ref#isPeeled()} will be true.
*
* Implementors should check {@link org.eclipse.jgit.lib.Ref#isPeeled()}
* before performing any additional work effort.
*
* @param ref
* The reference to peel
* @return {@code ref} if {@code ref.isPeeled()} is true; otherwise a new
* Ref object representing the same data as Ref, but isPeeled() will
* be true and getPeeledObjectId() will contain the peeled object
* (or {@code null}).
* @throws java.io.IOException
* the reference space or object space cannot be accessed.
*/
@NonNull
public abstract Ref peel(Ref ref) throws IOException;
/**
* Triggers a refresh of all internal data structures.
*
* In case the RefDatabase implementation has internal caches this method
* will trigger that all these caches are cleared.
*
* Implementors should overwrite this method if they use any kind of caches.
*/
public void refresh() {
// nothing
}
/**
* Try to find the specified name in the ref map using {@link #SEARCH_PATH}.
*
* @param map
* map of refs to search within. Names should be fully qualified,
* e.g. "refs/heads/master".
* @param name
* short name of ref to find, e.g. "master" to find
* "refs/heads/master" in map.
* @return The first ref matching the name, or {@code null} if not found.
* @since 3.4
*/
@Nullable
public static Ref findRef(MapgetRefs() but are accepted by {@link #findRef(String)}
* and {@link #exactRef(String)}.
*
* @return a list of additional refs
* @throws java.io.IOException
* the reference space cannot be accessed.
*/
@NonNull
public abstract List getAdditionalRefs() throws IOException;
/**
* Peel a possibly unpeeled reference by traversing the annotated tags.
*