[PATCH v8 0/3] git config cache & special querying api utilizing the cache

Hi,

[PATCH V8]: Moved the contents of config-set.c to config.c for future convenience. Reverted
	test 'find value with misspelled key' to the one in v5. See [10] for the discussion.

[PATCH V7]: Style nits and a broken && chain corrected in `t/t1308-config-set.sh`. See
	[9] for the nits.

[PATCH V6]: Style nits and mistakes corrected. Diff between v6 and v5[8] is at the bottom.
		Thanks to Matthieu, Ramsay and Ram for their suggestions.

[PATCH V5]: `config_set` now uses a single hashmap. Corrected style nits raised in
			the thread[7]. Thanks to Junio and Matthieu for their suggestions.

[PATCH v4]: Introduced `config_set` construct which points to a ordered set of
	config-files cached as hashmaps. Added relevant API functions. For more
	details see the documentation. Rewrote the git_config_get* family to use
	`config_set` internally. Added tests for both config_set API and git_config_get
	family. Added type specific API functions which parses the found value and
	converts it into a specific type.
	Most of the changes implemented are the result of discussion in [6].
	Thanks to Eric, Ramsay, Junio, Matthieu & Karsten for their suggestions
	and review.

[PATCH v3]: Added flag for NULL values that were causing segfaults in some cases.
	Added test-config for usage examples.
	Minor changes and corrections. Refer to discussion thread[5] for more details.
	Thanks to Matthieu, Jeff and Junio for their valuable suggestions.

[PATCH v2]:Changed the string_list to a struct instead of pointer to a struct.
	Added string-list initilization functions.
	Minor mistakes corrected acoording to review comments[4]. Thanks to
	Eric and Matthieu for their review.

[PATCH V1]:Most of the invaluable suggestions by Eric Sunshine, Torsten Bogershausen and
	Jeff King has been implemented[1]. Complete rewrite of config_cache*() family
	using git_config() as hook as suggested by Jeff. Thanks for the review.

[RFC V2]: Improved according to the suggestions by Eric Sunshine and Torsten Bogershausen.
	Added cache invalidation when config file is changed.[2]
	I am using git_config_set_multivar_in_file() as an update hook.

This is patch is for this year's GSoC. My project is "Git Config API improvements". The link of my proposal is appended below [3].

The aim of this patch series is to generate a cache for querying values from the config files in a non-callback manner as the current method reads and parses the config files every time a value is queried for.

The cache is generated from hooking the update_cache function to the current parsing and callback mechanism in config.c. It is implemented as an hashmap using the hashmap-api with variables and its corresponding values list as its members. The values in the list are sorted in order of increasing priority. The cache is initialised the first time when any of the new query functions is called. It is invalidated by using git_config_set_multivar_in_file() as an update hook.

We add two new functions to the config-api, git_config_get_string() and git_config_get_string_multi() for querying in a non callback manner from the cache.

[1] http://marc.info/?t=140172066200006&r=1&w=2 [2] http://git.661346.n2.nabble.com/RFC-PATCH-0-2-Git-config-cache-amp-special-querying-api-utilizing-the-cache-td7611691.html [3] https://drive.google.com/file/d/0B4suZ-aHqDcnSUZJRXVTTnZUN1E/edit?usp=sharing [4] http://thread.gmane.org/gmane.comp.version-control.git/251073/focus=251369 [5] http://thread.gmane.org/gmane.comp.version-control.git/251704/ [6] http://thread.gmane.org/gmane.comp.version-control.git/252329/ [7] http://marc.info/?t=140428115200001&r=1&w=2 [8] http://article.gmane.org/gmane.comp.version-control.git/252942/ [9] http://thread.gmane.org/gmane.comp.version-control.git/252959/ [10] http://article.gmane.org/gmane.comp.version-control.git/253113

Tanay Abhra (2):
  config set
  test-config

 .gitignore                             |   1 +
 Documentation/technical/api-config.txt | 134 +++++++++++++++
 Makefile                               |   1 +
 cache.h                                |  31 ++++
 config.c                               | 296 +++++++++++++++++++++++++++++++++
 t/t1308-config-set.sh                  | 170 +++++++++++++++++++
 test-config.c                          | 125 ++++++++++++++
 7 files changed, 758 insertions(+)
 create mode 100755 t/t1308-config-set.sh
 create mode 100644 test-config.c