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<title>git/tree.c, branch v2.3.3</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/git/git.git/
</subtitle>
<id>https://git.shady.money/git/atom?h=v2.3.3</id>
<link rel='self' href='https://git.shady.money/git/atom?h=v2.3.3'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/'/>
<updated>2014-12-01T19:32:29Z</updated>
<entry>
<title>tree.c: update read_tree_recursive callback to pass strbuf as base</title>
<updated>2014-12-01T19:32:29Z</updated>
<author>
<name>Nguyễn Thái Ngọc Duy</name>
<email>pclouds@gmail.com</email>
</author>
<published>2014-11-30T09:05:00Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=6a0b0b6de996e2ac7eeb951e3d08f577c11c7e54'/>
<id>urn:sha1:6a0b0b6de996e2ac7eeb951e3d08f577c11c7e54</id>
<content type='text'>
This allows the callback to use 'base' as a temporary buffer to
quickly assemble full path "without" extra allocation. The callback
has to restore it afterwards of course.

Helped-by: Eric Sunshine &lt;sunshine@sunshineco.com&gt;
Signed-off-by: Nguyễn Thái Ngọc Duy &lt;pclouds@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>add object_as_type helper for casting objects</title>
<updated>2014-07-14T01:59:05Z</updated>
<author>
<name>Jeff King</name>
<email>peff@peff.net</email>
</author>
<published>2014-07-13T06:42:03Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=8ff226a9d5ee065fe52752e6032f63cb6e4beccb'/>
<id>urn:sha1:8ff226a9d5ee065fe52752e6032f63cb6e4beccb</id>
<content type='text'>
When we call lookup_commit, lookup_tree, etc, the logic goes
something like:

  1. Look for an existing object struct. If we don't have
     one, allocate and return a new one.

  2. Double check that any object we have is the expected
     type (and complain and return NULL otherwise).

  3. Convert an object with type OBJ_NONE (from a prior
     call to lookup_unknown_object) to the expected type.

We can encapsulate steps 2 and 3 in a helper function which
checks whether we have the expected object type, converts
OBJ_NONE as appropriate, and returns the object.

Not only does this shorten the code, but it also provides
one central location for converting OBJ_NONE objects into
objects of other types. Future patches will use that to
enforce type-specific invariants.

Since this is a refactoring, we would want it to behave
exactly as the current code. It takes a little reasoning to
see that this is the case:

  - for lookup_{commit,tree,etc} functions, we are just
    pulling steps 2 and 3 into a function that does the same
    thing.

  - for the call in peel_object, we currently only do step 3
    (but we want to consolidate it with the others, as
    mentioned above). However, step 2 is a noop here, as the
    surrounding conditional makes sure we have OBJ_NONE
    (which we want to keep to avoid an extraneous call to
    sha1_object_info).

  - for the call in lookup_commit_reference_gently, we are
    currently doing step 2 but not step 3. However, step 3
    is a noop here. The object we got will have just come
    from deref_tag, which must have figured out the type for
    each object in order to know when to stop peeling.
    Therefore the type will never be OBJ_NONE.

Signed-off-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>move setting of object-&gt;type to alloc_* functions</title>
<updated>2014-07-14T01:59:05Z</updated>
<author>
<name>Jeff King</name>
<email>peff@peff.net</email>
</author>
<published>2014-07-13T06:41:55Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=d36f51c13b54a872cdaf08a1765a23afab26ae51'/>
<id>urn:sha1:d36f51c13b54a872cdaf08a1765a23afab26ae51</id>
<content type='text'>
The "struct object" type implements basic object
polymorphism.  Individual instances are allocated as
concrete types (or as a union type that can store any
object), and a "struct object *" can be cast into its real
type after examining its "type" enum.  This means it is
dangerous to have a type field that does not match the
allocation (e.g., setting the type field of a "struct blob"
to "OBJ_COMMIT" would mean that a reader might read past the
allocated memory).

In most of the current code this is not a problem; the first
thing we do after allocating an object is usually to set its
type field by passing it to create_object. However, the
virtual commits we create in merge-recursive.c do not ever
get their type set. This does not seem to have caused
problems in practice, though (presumably because we always
pass around a "struct commit" pointer and never even look at
the type).

We can fix this oversight and also make it harder for future
code to get it wrong by setting the type directly in the
object allocation functions.

This will also make it easier to fix problems with commit
index allocation, as we know that any object allocated by
alloc_commit_node will meet the invariant that an object
with an OBJ_COMMIT type field will have a unique index
number.

Signed-off-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'jk/free-tree-buffer'</title>
<updated>2013-09-17T18:37:33Z</updated>
<author>
<name>Junio C Hamano</name>
<email>gitster@pobox.com</email>
</author>
<published>2013-09-17T18:37:33Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=b8f23112f0415cc86eb0ec576ac7e16c7c9d78b8'/>
<id>urn:sha1:b8f23112f0415cc86eb0ec576ac7e16c7c9d78b8</id>
<content type='text'>
* jk/free-tree-buffer:
  clear parsed flag when we free tree buffers
</content>
</entry>
<entry>
<title>Merge branch 'jl/submodule-mv'</title>
<updated>2013-09-09T21:36:15Z</updated>
<author>
<name>Junio C Hamano</name>
<email>gitster@pobox.com</email>
</author>
<published>2013-09-09T21:36:15Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=b02f5aeda6f66ac3be9b2e35f9b237d4f1f80d73'/>
<id>urn:sha1:b02f5aeda6f66ac3be9b2e35f9b237d4f1f80d73</id>
<content type='text'>
"git mv A B" when moving a submodule A does "the right thing",
inclusing relocating its working tree and adjusting the paths in
the .gitmodules file.

* jl/submodule-mv: (53 commits)
  rm: delete .gitmodules entry of submodules removed from the work tree
  mv: update the path entry in .gitmodules for moved submodules
  submodule.c: add .gitmodules staging helper functions
  mv: move submodules using a gitfile
  mv: move submodules together with their work trees
  rm: do not set a variable twice without intermediate reading.
  t6131 - skip tests if on case-insensitive file system
  parse_pathspec: accept :(icase)path syntax
  pathspec: support :(glob) syntax
  pathspec: make --literal-pathspecs disable pathspec magic
  pathspec: support :(literal) syntax for noglob pathspec
  kill limit_pathspec_to_literal() as it's only used by parse_pathspec()
  parse_pathspec: preserve prefix length via PATHSPEC_PREFIX_ORIGIN
  parse_pathspec: make sure the prefix part is wildcard-free
  rename field "raw" to "_raw" in struct pathspec
  tree-diff: remove the use of pathspec's raw[] in follow-rename codepath
  remove match_pathspec() in favor of match_pathspec_depth()
  remove init_pathspec() in favor of parse_pathspec()
  remove diff_tree_{setup,release}_paths
  convert common_prefix() to use struct pathspec
  ...
</content>
</entry>
<entry>
<title>checkout: convert read_tree_some to take struct pathspec</title>
<updated>2013-07-15T17:56:08Z</updated>
<author>
<name>Nguyễn Thái Ngọc Duy</name>
<email>pclouds@gmail.com</email>
</author>
<published>2013-07-14T08:35:52Z</published>
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<id>urn:sha1:18e4f4059936dd35dfe929f502101ca371af856c</id>
<content type='text'>
Signed-off-by: Nguyễn Thái Ngọc Duy &lt;pclouds@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>Convert "struct cache_entry *" to "const ..." wherever possible</title>
<updated>2013-07-09T16:12:48Z</updated>
<author>
<name>Nguyễn Thái Ngọc Duy</name>
<email>pclouds@gmail.com</email>
</author>
<published>2013-07-09T15:29:00Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=9c5e6c802cde9881785b7f1b3278b97be4aabd82'/>
<id>urn:sha1:9c5e6c802cde9881785b7f1b3278b97be4aabd82</id>
<content type='text'>
I attempted to make index_state-&gt;cache[] a "const struct cache_entry **"
to find out how existing entries in index are modified and where. The
question I have is what do we do if we really need to keep track of on-disk
changes in the index. The result is

 - diff-lib.c: setting CE_UPTODATE

 - name-hash.c: setting CE_HASHED

 - preload-index.c, read-cache.c, unpack-trees.c and
   builtin/update-index: obvious

 - entry.c: write_entry() may refresh the checked out entry via
   fill_stat_cache_info(). This causes "non-const struct cache_entry
   *" in builtin/apply.c, builtin/checkout-index.c and
   builtin/checkout.c

 - builtin/ls-files.c: --with-tree changes stagemask and may set
   CE_UPDATE

Of these, write_entry() and its call sites are probably most
interesting because it modifies on-disk info. But this is stat info
and can be retrieved via refresh, at least for porcelain
commands. Other just uses ce_flags for local purposes.

So, keeping track of "dirty" entries is just a matter of setting a
flag in index modification functions exposed by read-cache.c. Except
unpack-trees, the rest of the code base does not do anything funny
behind read-cache's back.

The actual patch is less valueable than the summary above. But if
anyone wants to re-identify the above sites. Applying this patch, then
this:

    diff --git a/cache.h b/cache.h
    index 430d021..1692891 100644
    --- a/cache.h
    +++ b/cache.h
    @@ -267,7 +267,7 @@ static inline unsigned int canon_mode(unsigned int mode)
     #define cache_entry_size(len) (offsetof(struct cache_entry,name) + (len) + 1)

     struct index_state {
    -	struct cache_entry **cache;
    +	const struct cache_entry **cache;
     	unsigned int version;
     	unsigned int cache_nr, cache_alloc, cache_changed;
     	struct string_list *resolve_undo;

will help quickly identify them without bogus warnings.

Signed-off-by: Nguyễn Thái Ngọc Duy &lt;pclouds@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>clear parsed flag when we free tree buffers</title>
<updated>2013-06-06T17:29:12Z</updated>
<author>
<name>Jeff King</name>
<email>peff@peff.net</email>
</author>
<published>2013-06-05T22:37:39Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=6e454b9a31840102807f1eee527ee717bf134102'/>
<id>urn:sha1:6e454b9a31840102807f1eee527ee717bf134102</id>
<content type='text'>
Many code paths will free a tree object's buffer and set it
to NULL after finishing with it in order to keep memory
usage down during a traversal. However, out of 8 sites that
do this, only one actually unsets the "parsed" flag back.
Those sites that don't are setting a trap for later users of
the tree object; even after calling parse_tree, the buffer
will remain NULL, causing potential segfaults.

It is not known whether this is triggerable in the current
code. Most commands do not do an in-memory traversal
followed by actually using the objects again. However, it
does not hurt to be safe for future callers.

In most cases, we can abstract this out to a
"free_tree_buffer" helper. However, there are two
exceptions:

  1. The fsck code relies on the parsed flag to know that we
     were able to parse the object at one point. We can
     switch this to using a flag in the "flags" field.

  2. The index-pack code sets the buffer to NULL but does
     not free it (it is freed by a caller). We should still
     unset the parsed flag here, but we cannot use our
     helper, as we do not want to free the buffer.

Signed-off-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>Strip namelen out of ce_flags into a ce_namelen field</title>
<updated>2012-07-11T16:42:45Z</updated>
<author>
<name>Thomas Gummerer</name>
<email>t.gummerer@gmail.com</email>
</author>
<published>2012-07-11T09:22:37Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=b60e188c51242b72061b5f2f0d4df80397f6125a'/>
<id>urn:sha1:b60e188c51242b72061b5f2f0d4df80397f6125a</id>
<content type='text'>
Strip the name length from the ce_flags field and move it
into its own ce_namelen field in struct cache_entry. This
will both give us a tiny bit of a performance enhancement
when working with long pathnames and is a refactoring for
more readability of the code.

It enhances readability, by making it more clear what
is a flag, and where the length is stored and make it clear
which functions use stages in comparisions and which only
use the length.

It also makes CE_NAMEMASK private, so that users don't
mistakenly write the name length in the flags.

Signed-off-by: Thomas Gummerer &lt;t.gummerer@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>tree_entry_interesting(): give meaningful names to return values</title>
<updated>2011-10-27T18:38:24Z</updated>
<author>
<name>Nguyễn Thái Ngọc Duy</name>
<email>pclouds@gmail.com</email>
</author>
<published>2011-10-24T06:36:10Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=d688cf07b15b664a2164c3d92bcb5e8265400a2b'/>
<id>urn:sha1:d688cf07b15b664a2164c3d92bcb5e8265400a2b</id>
<content type='text'>
It is a basic code hygiene to avoid magic constants that are unnamed.
Besides, this helps extending the value later on for "interesting, but
cannot decide if the entry truely matches yet" (ie. prefix matches)

Signed-off-by: Nguyễn Thái Ngọc Duy &lt;pclouds@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
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