Google Code Search: Difference between revisions

Revision as of 11:26, 13 September 2016

Revision as of 12:24, 24 September 2016

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'''Google Code Search''' was a free [[Development stage#Beta|beta]] product from [[Google]] which debuted in [[Google Labs]] on October 5, 2006 allowing web users to search for open-source code on the Internet. GoogleFeatures announcedincluded thatthe Code Search wasability to besearch shutusing downoperators, alongnamely with the Code Search API on January 15<tt>lang:</tt>, 2012.<reftt>{{cite web|last=Horowitz |first=Bradley |url=httppackage:<//googleblog.blogspot.com/2011/10/fall-sweep.htmltt>, |title=Official Blog<tt>license: A fall sweep |publisher=Googleblog.blogspot.com |date=2011-10-14 |accessdate=2013-07-09}}</reftt> Theand service remained online until March 2013,<reftt>httpsfile://stackoverflow.com/questions/7778034/replacement-for-google-code-search</reftt> and it now returns a [[HTTP 404|404]].

The code available for searching was in various formats including tar.gz, .tar.bz2, .tar, and .zip, [[Concurrent VersioningVersions System|CVS]], [[Subversion (software)|Subversion]], [[Git (software)|git]] and [[Mercurial]] repositories.

Features included the ability to search using operators. These are <tt>lang:</tt>, <tt>package:</tt>, <tt>license:</tt> and <tt>file:</tt>.

The code available for searching was in various formats including tar.gz, .tar.bz2, .tar, and .zip, [[Concurrent Versioning System|CVS]], [[Subversion (software)|Subversion]], [[Git (software)|git]] and [[Mercurial]] repositories.

== Regular expression engine ==

The site allowed the use of [[regular expressionsexpression]]s in queries, which isat the time was not offered by any other search engine for code.{{Citation needed|date=October 2009}} This makes it resemble [[grep]], but over the world's public code. The methodology employed combines a [[trigram]] [[Search engine indexing|index]] with a custom-built, [[ReDoS|denial-of-service]] resistant [[regular expression]] engine.<ref>{{URLcite web |url = http://swtch.com/~rsc/regexp/regexp4.html |title = Regular Expression Matching with a Trigram Index (or: How Google Code Search Worked}},) |author = Russ Cox, |date = January 2012 }}</ref>

In March 2010, the code of [[RE2]], the regular expression engine used in Google Code Search, was made open source.<ref>[https://opensource.googleblog.com/2010/03/re2-principled-approach-to-regular.html Google Open Source Blog: RE2: a principled approach to regular expression matching]</ref>

Google Code Search supported POSIX extended regular expression syntax, excluding back-references, collating elements, and collation classes.

Languages not officially supported could be searched for using the file: operator to match the common file extensions for the language.

== Discontinuation ==

In October 2011, Google announced that Code Search was to be shut down along with the Code Search API.<ref>{{cite web |last = Horowitz |first = Bradley |url = http://googleblog.blogspot.com/2011/10/fall-sweep.html |title = Official Blog: A fall sweep |publisher = Googleblog.blogspot.com |date = 2011-10-14 |accessdate = 2013-07-09 }}</ref> The service remained online until March 2013,<ref>https://stackoverflow.com/questions/7778034/replacement-for-google-code-search</ref> and it now returns a [[HTTP 404|404]].

In January 2012, Russ Cox published an overview of history and the technical aspects of the tool, and open-sourced a basic implementation of a similar functionality as a set of standalone programs that can run fast indexed regular expression searches over local code.<ref>{{github|google/codesearch}}</ref>

== See also ==

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* [[Codase]]

* [[Krugle]]

* [[Black Duck Open Hub|Open Hub]] (a merge of Ohloh and [[Koders]])

* [[Merobase]]

* [[OpenGrok]]