Merge pull request #1674 from github/rework-heuristics

Rework heuristics
This commit is contained in:
Arfon Smith
2014-11-18 10:43:01 -06:00
8 changed files with 94 additions and 70 deletions

View File

@@ -100,12 +100,8 @@ module Linguist
def self.detect(blob)
name = blob.name.to_s
# Check if the blob is possibly binary and bail early; this is a cheap
# test that uses the extension name to guess a binary binary mime type.
#
# We'll perform a more comprehensive test later which actually involves
# looking for binary characters in the blob
return nil if blob.likely_binary? || blob.binary?
# Bail early if the blob is binary or empty.
return nil if blob.likely_binary? || blob.binary? || blob.empty?
# A bit of an elegant hack. If the file is executable but extensionless,
# append a "magic" extension so it can be classified with other
@@ -124,16 +120,18 @@ module Linguist
if possible_languages.length > 1
data = blob.data
possible_language_names = possible_languages.map(&:name)
heuristic_languages = Heuristics.find_by_heuristics(data, possible_language_names)
if heuristic_languages.size > 1
possible_language_names = heuristic_languages.map(&:name)
end
# Don't bother with binary contents or an empty file
if data.nil? || data == ""
nil
# Check if there's a shebang line and use that as authoritative
elsif (result = find_by_shebang(data)) && !result.empty?
if (result = find_by_shebang(data)) && !result.empty?
result.first
# No shebang. Still more work to do. Try to find it with our heuristics.
elsif (determined = Heuristics.find_by_heuristics(data, possible_language_names)) && !determined.empty?
determined.first
elsif heuristic_languages.size == 1
heuristic_languages.first
# Lastly, fall back to the probabilistic classifier.
elsif classified = Classifier.classify(Samples.cache, data, possible_language_names).first
# Return the actual Language object based of the string language name (i.e., first element of `#classify`)