Optional inCore parameter to Resolver/Strategy will
instruct it to perform all the operations in memory
and avoid modifying working folder even if there is one.
Most diff implementations really want to use cached hash codes for
elements, rather than element equality, as they need to perform many
compares and unique hash codes for elements can really speed that
process up.
To make it easier to define element hash functions, move the caching
of hash codes into a wrapper sequence type, so that individual
sequence types like RawText don't need to do this themselves. This
has a nice property of also allowing the sequence to no longer care
about the specific SequenceComparator that is going to be used, and
permits the caching to only examine the middle region that isn't
common to the two inputs.
Change-Id: If8623556da9419117b07c5073e8bce39de02570e Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
This is a faster exact match based form that tries to improve
performance for the common case of the header and trailer of
a text file not changing at all. After this fast path we use
the slower path based on the super class' using equals() to
allow for whitespace ignore modes to still work.
Some simple performance testing showed a major improvement over the
older implementation for a common edit we see in JGit. The test
compared blob 29a89bc and 372a978, which is the ObjectDirectory.java
file difference in commit 41dd9ed1c054f9f9e1ab52fc7bbf1a55a56cf543.
The two text files are approximately 22 KiB in size.
DEFAULT old 203900 ns
DEFAULT new 100400 ns
This new version is 2x faster for the DEFAULT comparator, which does
not treat space specially. This is because we can now examine a
larger swath of text with fewer instructions per byte compared. The
older algorithm had to stop at each line break and recompute how to
examine the next line, while the new algorithm only stops when the
first difference is found.
WS_IGNORE_ALL old 298500 ns
WS_IGNORE_ALL new 63300 ns
Its 4.7x faster for the whitespace ignore comparator, as the common
header and footer do not have a whitespace difference. Avoiding the
special case handling for whitespace on each byte considered saves a
lot of time.
Since most edits to source code (and other text like files) appears in
the interior of the file, fast elimination of common header/footer
means faster diff throughput. In the less common case of an actual
header or footer edit, the common header/footer elimination is stopped
rather quickly either way, so there is very little downside to the
optimiation applied here.
Change-Id: I1d501b4c3ff80ed086b20bf12faf51ae62167db7 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
DiffAlgorithm implementations may find it useful to construct an Edit
and use that to later subsequence the two base sequences, so define
two new utility methods a() and b() to construct the A and B ranges.
Once a subsequence has had Edits created for it the indexes are
within the space of the subsequence. These must be shifted back to
the original base sequence's indexes. Define toBase() as a utility
method to perform that shifting work in-place, so DiffAlgorithm
implementations have an efficient way to convert back to the caller's
original space.
Change-Id: I8d788e4d158b9f466fa9cb4a40865fb806376aee Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Fix UnsupportedOperationException while fixing thin pack
If a thin pack has a large delta we need to be able to open
its cached copy from the loose object directory through the
CachedObjectDatabase handle. Unfortunately that did not support the
openObject2 method, which the LargePackedDeltaObject used directly
to bypass looking at the pack files.
Bug: 324868
Change-Id: I1d5886a6c3254c6dea2852d50b8614c31a93e615 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Stefan Lay [Fri, 17 Sep 2010 14:24:08 +0000 (16:24 +0200)]
Remove unnecessary failing test method
Method test006_readCaseInsensitive in TestConfig already does the
same thing, and doesn't require an OS specific test for the value being
asserted.
This is additionally a fast fix for the failing JUnit test after
change 3fe5276.
Change-Id: I96d2794dbc7db55bdd0fbfcf675aabb15cc8419f Signed-off-by: Stefan Lay <stefan.lay@sap.com>
* stable-0.9:
Qualify post-0.9.3 builds
JGit 0.9.3
clone: Correct formatting of init message
Fix cloning of repositories with big objects
Qualify post-0.9.1 builds
JGit 0.9.1
Fix PlotCommitList to set lanes on child-less commits
When running IndexPack we use a CachedObjectDirectory, which
knows what objects are loose and tries to avoid stat(2) calls for
objects that do not exist in the repository, as stat(2) on Win32
is very slow.
However large delta objects found in a pack file are expanded into
a loose object, in order to avoid costly delta chain processing
when that object is used as a base for another delta.
If this expand occurs while working with the CachedObjectDirectory,
we need to update the cached directory data to include this new
object, otherwise it won't be available when we try to open it
during the object verify phase.
Bug: 324868
Change-Id: Idf0c76d4849d69aa415ead32e46a435622395d68 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
When creating a new FileRepository, probe the capability of the
local filesystem and set core.filemode based on how it reacts.
We can't just rely on FS.supportsExecute() because a POSIX system
(which usually does support execute) might be storing the repository
on a partition that doesn't have execute support (e.g. plain FAT-32).
Creating a temporary file, setting both states, checking we get
the desired results will let us set the variable correctly on
all systems.
Change-Id: I551488ea8d352d2179c7b244f474d2e3d02567a2 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Fix PlotCommitList to set lanes on child-less commits
In PlotCommitList.enter() commits are positioned on lanes for visual
presentation. This implementation was buggy: commits without
children (often the starting points for the RevWalk) are not positioned
on separate lanes.
The problem was that when handling commits with multiple children
(that's where branches fork out) it was not handled that some of the
children may not have been positioned on a lane yet. I fixed that and
added a number of tests which specifically test the layout of commits
on lanes.
Bug: 300282
Bug: 320263
Change-Id: I267b97ecccb5251cec54cec90207e075ab50503e Signed-off-by: Christian Halstrick <christian.halstrick@sap.com> Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
A diff algorithm may find this type useful if it wants to delegate a
particular range of elements to another algorithm, without changing
the underlying sequence types.
Change-Id: I4544467781233e21ac8b35081304b2bad7db00f6 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
git allows remotes to be relative paths, but the regex
validating urls wouldn't accept anything starting with "..".
Other functionality works fine with these paths.
Instead of spooling large delta bases into temporary files and then
immediately deleting them afterwards, spool the large delta out to
a normal loose object. Later any requests for that large delta can
be answered by reading from the loose object, which is much easier
to stream efficiently for readers.
Since the object is now duplicated, once in the pack as a delta and
again as a loose object, any future prune-packed will automatically
delete the loose object variant, releasing the wasted disk space.
As prune-packed is run automatically during either repack or gc, and
gc --auto triggers automatically based on the number of loose objects,
we get automatic cache management for free. Large objects that were
unpacked will be periodically cleared out, and will simply be restored
later if they are needed again.
After a short offline discussion with Junio Hamano today, we may want
to propose a change to prune-packed to hold onto larger loose objects
which also exist in pack files as deltas, if the loose object was
recently accessed or modified in the last 2 days.
Change-Id: I3668a3967c807010f48cd69f994dcbaaf582337c Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Remember loose objects and fast-track their lookup
Recently created objects are usually what branches point to, and
are usually written out as loose objects. But due to the high cost
of asking the operating system if a file exists, these are the last
thing that ObjectDirectory examines when looking for an object by
its ObjectId.
Caching recently seen loose objects permits the opening code to
jump directly to the loose object, accelerating lookup for branch
heads that are accessed often.
To avoid exploding the cache its limited to approximately 2048
entries. When more ids are added, the table is simply cleared
and reset in size.
Change-Id: I18f483217412b102f754ffd496c87061d592e535 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
This class is used only to cache the unpacked form of an object that
was used as a base for another object. The theory goes that if an
object is used as a delta base for A, it will probably also be a
delta base for B, C, D, E, etc. and therefore having an unpacked copy
of it on hand will make delta resolution for the others very fast.
However since objects are usually only accessed once, we don't want
to cache everything we unpack, just things that we are likely to
need again. The only things we need again are the delta bases.
Hence, its a delta base cache.
This gets us the class name UnpackedObjectCache back, so we can
use it to actually create a cache of unpacked object information.
Change-Id: I121f356cf4eca7b80126497264eac22bd5825a1d Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
The core.autocrlf variable can take on three values: false, true,
and input. Parsing it as a boolean is wrong, we instead need to
parse a tri-state enumeration.
Add support for parsing and setting enum values from Java from and
to the text based configuration file, and use that to handle the
autocrlf variable.
Bug: 301775
Change-Id: I81b9e33087a33d2ef2eac89ba93b9e83b7ecc223 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Instead of making the sequence itself responsible for the equivalence
function, use an external function that is supplied by the caller.
This cleans up the code because we now say cmp.equals(a, ai, b, bi)
instead of a.equals(ai, b, bi).
This refactoring also removes the odd concept of creating different
types of sequences to have different behaviors for whitespace
ignoring. Instead DiffComparator now supports singleton functions
that apply a particular equivalence algorithm to a type of sequence.
Change-Id: I559f494d81cdc6f06bfb4208f60780c0ae251df9 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Fix checkReferencedIsReachable to use correct base list
When checkReferencedIsReachable is set in ReceivePack we are trying
to prove that the push client is permitted to access an object that
it did not send to us, but that the received objects link to either
via a link inside of an object (e.g. commit parent pointer or tree
member) or by a delta base reference.
To do this check we are making a list of every potential delta base,
and then ensuring that every delta base used appears on this list.
If a delta base does not appear on this list, we abort with an error,
letting the client know we are missing a particular object.
Preventing spurious errors about missing delta base objects requires
us to use the exact same list of potential delta bases as the remote
push client used. This means we must use TOPO ordering, and we
need to enable BOUNDARY sorting so that ObjectWalk will correctly
include any trees found during the enumeration back to the common
merge base between the interesting and uninteresting heads.
To ensure JGit's own push client matches this same potential delta
base list, we need to undo 60aae90d4d15 ("Disable topological
sorting in PackWriter") and switch back to using the conventional
TOPO ordering for commits in a pack file. This ensures that our
own push client will use the same potential base object list as
checkReferencedIsReachable uses on the receiving side.
Change-Id: I14d0a326deb62a43f987b375cfe519711031e172 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Since we are only checking the links between objects we don't need
to hold onto commit messages after their headers have been parsed
by the walker. Dropping them saves a bit of memory, which is always
good when accepting huge pack files.
Change-Id: I378920409b6acf04a35cdf24f81567b1ce030e36 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
DeltaStream: Fix data corruption when reading large copies
If the copy instruction was larger than the input buffer given to us,
we copied the wrong part of the base stream during the next read().
This occurred on really big binary files where a copy instruction
of 64k wasn't unreasonable, but the caller's buffer was only 8192
bytes long. We copied the first 8192 bytes correctly, but then
reseeked the base stream back to the start of the copy region on
the second read of 8192 bytes. Instead of a sequence like ABCD
being read into the caller, we read AAAA.
Change-Id: I240a3f722a3eda1ce8ef5db93b380e3bceb1e201 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Use 8192 as default buffer size in ObjectLoader copyTo
As ObjectStreams are supposed to be buffered, most implementors will
be wrapping their underlying stream inside of a BufferedInputStream
in order to satisfy this requirement. Because developers are by
nature lazy, they will use the default buffer size rather than
specify their own.
The OpenJDk JRE implementations use 8192 as the default buffer
size, and when the higher level reader uses the same buffer size
the buffers "stack" nicely by avoiding a copy to the internal
buffer array. As OpenJDK is a popular virtual machine, we should
try to benefit from this nice stacking property during copyTo().
Change-Id: I69d53f273b870b841ced2be2e9debdfd987d98f4 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
We can slightly optimize this method by removing some compares
based on knowledge of how the orderings have to work. This way
a getType() invocation requires at most 2 int compares for any
result, vs. the 6 required to find REPLACE before.
Change-Id: I62a04cc513a6d28c300d1c1496a8608d5df4efa6 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Exposing isEmpty, getLengthA, getLengthB make it easier to examine
the state of an edit and work with it from higher level code.
The before and after cut routines make it easy to split an edit
that contains another edit, such as to decompose a REPLACE that
contains a common sequence within it.
Change-Id: Id63d6476a7a6b23acb7ab237d414a0a1a7200290 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
We weren't flushing the commit message before the diff output, which
meant the headers and message showed randomly interleaved with the
diff rather than immediately before.
Change-Id: I6cefab8d40e9d40c937e9deb12911188fec41b26 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
We shouldn't escape non-special ASCII characters such as '@' or '~'.
These are valid in a path name on POSIX systems, and may appear as
part of a path in a GNU or Git style patch script. Escaping them
into octal just obfuscates the user's intent, with no gain.
When parsing an escaped octal sequence, we must parse no more
than 3 digits. That is, "\1002" is actually "@2", not the Unicode
character \u0202.
Change-Id: I3a849a0d318e69b654f03fd559f5d7f99dd63e5c Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
QuotedString.GIT_PATH returns the input reference exactly if
the string does not require quoting, otherwise it returns a
copy that contains the quotes on either end, plus escapes in
the middle where necessary to meet conventions.
Testing the return against '"' + name + '"' is always false,
because GIT_PATH will never return it that way. The only way
we have quotes on either end is if there is an escape in the
middle, in which case the string isn't equal anyway.
Change-Id: I4d21d8e5c7da0d7df9792c01ce719548fa2df16b Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
ReceivePack: Rethrow exceptions caught during indexing
If we get an exception while indexing the incoming pack, its likely
a stream corruption. We already report an error to the client, but
we eat the stack trace, which makes debugging issues related to a
bug inside of JGit nearly impossible. Rethrow it under a new type
UnpackException, so embedding servers or applications can catch the
error and provide it to a human who might be able to forward such
traces onto a JGit developer for evaluation.
Change-Id: Icad41148bbc0c76f284c7033a195a6b51911beab Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Instead of getting the limit from CoreConfig, use the larger of the
reader's limit or 5 MiB, under the assumption that any annotated tag
or commit of interest should be under 5 MiB. But if a repository
was really insane and had bigger objects, the reader implementation
can set its streaming limit higher in order to allow RevWalk to
still process it.
Change-Id: If2c15235daa3e2d1f7167e781aa83fedb5af9a30 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Shawn O. Pearce [Tue, 31 Aug 2010 20:13:28 +0000 (13:13 -0700)]
Move ObjectDirectory streaming limit to WindowCacheConfig
IDEs like Eclipse offer up the settings in WindowCacheConfig to the
user as a global set of options that are configured for the entire
JVM process, not per-repository, as the cache is shared across the
entire JVM. The limit on how much we are willing to allocate for
an object buffer is similar to the limit on how much we can use for
data caches, allocating that much space impacts the entire JVM and
not just a single repository, so it should be a global limit.
Change-Id: I22eafb3e223bf8dea57ece82cd5df8bfe5badebc Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
If the iterators passed into a diff formatter are working tree
iterators, we should enable ignoring files that are ignored, as
well as actually pull up the current content from the working tree
rather than getting it from the repository.
Because we abstract away the working directory access logic,
we can now actually support rename detection between the working
directory and the local repository when using a DiffFormatter.
This means its possible for an application to show an unstaged
delete-add pair as a rename if the add path is not ignored.
(Because the ignored file wouldn't show up in our difference output.)
Even more interesting is we can now do rename detection between any
two working trees, if both input iterators are WorkingTreeIterators.
Unfortunately we don't (yet) optimize for comparing the working
tree with the index involved so we can take advantage of cached
stat data to rule out non-dirty paths.
Change-Id: I4c0598afe48d8f99257266bf447a0ecd23ca7f5e Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Fix TreeWalk bug comparing DirCache and WorkingTree with ANY_DIFF
When comparing a DirCache and a WorkingTree using ANY_DIFF we
sometimes didn't recursive into a subtree of both sides gave us
zeroId() back for the identity of a subtree. This happens when the
DirCache doesn't have a valid cache tree for the subtree, as then
it uses zeroId() for the ObjectId of the subtree, which then appears
to be equal to the zeroId() of the WorkingTreeIterator's subtree.
We work around this by adding a hasId() method that returns true
only if this iterator has a valid ObjectId. The idEquals method
on TreeWalk than only performs a compare between two iterators if
both iterators have a valid id.
Change-Id: I695f7fafbeb452e8c0703a05c02921fae0822d3f Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Move rename detection, path following into DiffFormatter
Applications just want a quick way to configure our diff
implementation, and then just want to use it without a lot of fuss.
Move all of the rename detection logic and path following logic
out of our pgm package and into DiffFormatter itself, making it
much easier for a GUI to take advantage of the features without
duplicating a lot of code.
Change-Id: I4b54e987bb6dc804fb270cbc495fe4cae26c7b0e Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Sorting the array can be useful when its being used as a map of pairs
that are appended into the array and then later merge-joined against
another array of similar semantics.
Change-Id: I2e346ef5c99ed1347ec0345b44cda0bc29d03e90 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
We know exactly how many lines we need by the time we compute our
per-line hashes, as we have already built the lines IntList to give
us the starting position of each line in the buffer. Using that
we can properly size the array, and don't need the dynamic growing
feature of IntList. So drop the indirection and just use a fixed
size array.
Change-Id: I5c8c592514692a8abff51e5928aedcf71e100365 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Add toString and improve Javadoc of NotIgnoredFilter
Today while debugging some TreeWalk related code I noticed this
filter did not have a toString(), making it harder to see what the
filter graph was at a glance in the debugger. Add a toString()
for debugging to match other TreeFilters, and clean up the Javadoc
slightly so its a bit more clear about the purpose of the filter.
While we are mucking about with some of this code, simplify
the logic of include so its shorter and thus faster to read.
The pattern now more closely matches that of SkipWorkTreeFilter.
Change-Id: Iad433a1fa6b395dc1acb455aca268b9ce2f1d41b Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
This allows callers to force the iterator back to its starting point,
so it can be traversed again. The default way to do this is to use
back(1) until first() is true, but this isn't very efficient for any
iterator. All current implementations have better ways to implement
reset without needing to seek backwards.
Change-Id: Ia26e6c852fdac8a0e9c80ac72c8cca9d897463f4 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
When we are asked to create a difference between two files the caller
really wants to see that output. Instead of punting because a file
is too big to process, consider it to be binary. This reduces the
accuracy of our output display, but makes it a lot more likely that
the formatter can still generate something semi-useful.
We set our default binary threshold to 50 MiB, which is the same
threshold that PackWriter uses before punting and deciding a file
is too big to delta compress. Anything under this size we try to
load and process, anything over that size (or that won't allocate
in the heap) gets tagged as binary.
Change-Id: I69553c9ef96db7f2058c6210657f1181ce882335 Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
When adding or deleting a file, we shouldn't ever prefix /dev/null
with the a/ or b/ prefixes. Doing so is a mistake and confuses a
patch parser which handles /dev/null magically, while a/dev/null is
a file called null in the dev directory of the project.
Also when adding or deleting the "diff --git" line has the "real"
path on both sides, so we should see the following when adding the
file called foo:
diff --git a/foo b/foo
--- /dev/null
+++ b/foo
The --- and +++ lines do not appear in a pure rename or copy delta,
C Git diff seems to omit these, so we now omit them as well. We also
omit the index line when the ObjectIds are exactly equal.
Change-Id: Ic46892dea935ee8bdee29088aab96307d7ec6d3d Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Instead of trying to stream out the header, we can drop a redundant
code path by formatting the header into a temporary buffer and then
streaming out the actual line differences later.
Its a small amount of unnecessary work to buffer the file header,
but these are typically very tiny so the cost to format and reparse
is relatively low.
Change-Id: Id14a527a74ee0bd7e07f46fdec760c22b02d5bdf Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Marc Strapetz [Wed, 1 Sep 2010 15:14:16 +0000 (17:14 +0200)]
Add FS.detect() for detection of file system abstraction.
To give the user more control on which file system abstraction
should be used on Windows, FS.detect() may be configured
to assume a Cygwin installation or nor.
Currently, if a branch is created that has special chars ('#' in the bug),
Config will surround the subsection name with double quotes during
it's toText method which will result in an invalid file after saving the
Config.
Marc Strapetz [Tue, 31 Aug 2010 11:26:29 +0000 (13:26 +0200)]
Partial support for index file format "3".
Extended flags are processed and available via DirCacheEntry's
new isSkipWorkTree() and isIntentToAdd() methods. "resolve-undo"
information is completely ignored since its an optional extension.
Improve MergeAlgorithm to produce smaller conflicts
The merge algorithm was reporting conflicts which where to big.
Example: The common base was "ABC", the "ours" version contained
"AB1C" (the addition of "1" after pos 2) and the "theirs" version also
contained "AB1C". We have two potentially conflicting edits in the
same region which happen to bring in exactly the same content. This
should not be a conflict - but was previously reported as
"AB<<<1===1>>>C".
This is fixed by checking every conflicting chunk whether the
conflicting regions have a common prefix or suffix and by removing
this regions from the conflict.
Change-Id: I4dc169b8ef7a66ec6b307e9a956feef906c9e15e Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
This adds the first merge strategy to JGit which does real
content-merges if necessary. The new merge strategy "resolve" takes as
input three commits: a common base, ours and theirs. It will simply takeover
changes on files which are only touched in ours or theirs. For files
touched in ours and theirs it will try to merge the two contents
knowing taking into account the specified common base.
Rename detection has not been introduced for now.
Change-Id: I49a5ebcdcf4f540f606092c0f1dc66c965dc66ba Signed-off-by: Christian Halstrick <christian.halstrick@sap.com> Signed-off-by: Stefan Lay <stefan.lay@sap.com>
Matthias Sohn [Sun, 29 Aug 2010 21:41:10 +0000 (23:41 +0200)]
Wait for JIT optimization before measuring diff performance
On Mac OS X MyerDiffPerformanceTest was failing since during the
first few tests the JIT compiler is running in parallel slowing down
the tests. When setting the JVM option -Xbatch forcing the JIT to do
its work prior to running the code this effect can be avoided. Instead
we chose to run some tests without recording prior to the recorded
tests since relying on -X JVM parameters isn't portable across JVMs.
Use 10k * powers of 2 as sample size instead of odd numbers used
before and also improve formatting of performance readings.
Bug: 323766
Change-Id: I9a46d73f81a785f399d3cf5a90c8c0516526e048 Signed-off-by: Matthias Sohn <matthias.sohn@sap.com> Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>
Matthias Sohn [Fri, 27 Aug 2010 23:18:20 +0000 (01:18 +0200)]
Generate source plugin and source feature for jgit
Change-Id: Ibc5a302078bfc01d9ee45a4c0ab0b79b2abd185a Signed-off-by: Matthias Sohn <matthias.sohn@sap.com> Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>
projects / jgit.git / log