README
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License Classifier v2
This is a substantial revision of the license classifier with a focus on improved accuracy and performance.
Glossary
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corpus dictionary - contains all the unique tokens stored in the corpus of documents to match. Any tokens in the target document that aren't in the corpus dictionary are mapped to an invalid value.
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document - an internal-only data type that contains sequenced token information for a source or target content for matching.
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source content - a body of text that can be matched by the scanner.
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target content - the argument to Match that is scanned for matches with source content.
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indexed document - an internal-only data type that maps a document to the corpus dictionary, resulting in a compressed representation suitable for fast text searching and mapping operations. an indexed document is necessarily tightly coupled to its corpus.
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frequency table - a lookup table holding per-token counts of the number of times a token appears in content. used for fast filtering of target content against different source contents.
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q-gram - a substring of content of length q tokens used to efficiently match ranges of text. For background on the q-gram algorithms used, please see Indexing Methods for Approximate String Matching
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searchset - a data structure that uses q-grams to identify ranges of text in the target that correspond to a range of text in the source. The searchset algorithms compensate for the allowable error in matching text exactly, dealing with additional or missing tokens.
Migrating from v1
The API for the classifier versions is quite similar, but there are two key distinctions to be aware of while migrating usages.
The confidence value for the v2 classifier is applied uniformly to results; it will never return a match that is lower confidence than the threshold. In v1, MultipleMatch behaved this way, but NearestMatch would return a value regardless of the confidence match. Users often verified that the confidence was above the threshold, but this is no longer necessary.
The second change is that the classifier now returns all matches against the supplied corpus. The v1 classifier allowed filtering on header matches via a boolean field. This can be emulated by creating a license classifier with a reduced corpus if matching against headers is not desired. Alternatively, the user can use the MatchType field in the Match struct to filter out unwanted matches.
Documentation
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Overview ¶
Package classifier provides the implementation of the v2 license classifier.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func LicenseName ¶
LicenseName produces the output name for a license, removing the internal structure of the filename in use.
Types ¶
type Classifier ¶
type Classifier struct {
// contains filtered or unexported fields
}
Classifier provides methods for identifying open source licenses in text content.
func NewClassifier ¶
func NewClassifier(threshold float64) *Classifier
NewClassifier creates a classifier with an empty corpus.
func (*Classifier) AddContent ¶
func (c *Classifier) AddContent(name string, content []byte)
AddContent incorporates the provided textual content into the classifier for matching. This will not modify the supplied content.
func (*Classifier) LoadLicenses ¶
func (c *Classifier) LoadLicenses(dir string) error
LoadLicenses adds the contents of the supplied directory to the corpus of the classifier.
func (*Classifier) Match ¶
func (c *Classifier) Match(in []byte) Matches
Match finds matches within an unknown text. This will not modify the contents of the supplied byte slice.
func (*Classifier) MatchFrom ¶
func (c *Classifier) MatchFrom(in io.Reader) (Matches, error)
MatchFrom finds matches within the read content.
func (*Classifier) SetTraceConfiguration ¶
func (c *Classifier) SetTraceConfiguration(in *TraceConfiguration)
SetTraceConfiguration installs a tracing configuration for the classifier.
type Match ¶
type Match struct {
Name string
Confidence float64
MatchType string
StartLine int
EndLine int
StartTokenIndex int
EndTokenIndex int
}
Match is the information about a single instance of a detected match.
type TraceConfiguration ¶
type TraceConfiguration struct {
// Comma-separated list of phases to be traced. Can use * for all phases.
TracePhases string
// Comma-separated list of licenses to be traced. Can use * as a suffix to
// match prefixes, or by itself to match all licenses.
TraceLicenses string
// Tracer specifies a TraceFunc used to capture tracing information.
// If not supplied, emits using fmt.Printf
Tracer TraceFunc
// contains filtered or unexported fields
}
TraceConfiguration specifies the configuration for tracing execution of the license classifier.
Source Files