11 "golang.org/x/tools/internal/analysisinternal"
14 // An Analyzer describes an analysis function and its options.
15 type Analyzer struct {
16 // The Name of the analyzer must be a valid Go identifier
17 // as it may appear in command-line flags, URLs, and so on.
20 // Doc is the documentation for the analyzer.
21 // The part before the first "\n\n" is the title
22 // (no capital or period, max ~60 letters).
25 // Flags defines any flags accepted by the analyzer.
26 // The manner in which these flags are exposed to the user
27 // depends on the driver which runs the analyzer.
30 // Run applies the analyzer to a package.
31 // It returns an error if the analyzer failed.
33 // On success, the Run function may return a result
34 // computed by the Analyzer; its type must match ResultType.
35 // The driver makes this result available as an input to
36 // another Analyzer that depends directly on this one (see
37 // Requires) when it analyzes the same package.
39 // To pass analysis results between packages (and thus
40 // potentially between address spaces), use Facts, which are
42 Run func(*Pass) (interface{}, error)
44 // RunDespiteErrors allows the driver to invoke
45 // the Run method of this analyzer even on a
46 // package that contains parse or type errors.
49 // Requires is a set of analyzers that must run successfully
50 // before this one on a given package. This analyzer may inspect
51 // the outputs produced by each analyzer in Requires.
52 // The graph over analyzers implied by Requires edges must be acyclic.
54 // Requires establishes a "horizontal" dependency between
55 // analysis passes (different analyzers, same package).
58 // ResultType is the type of the optional result of the Run function.
59 ResultType reflect.Type
61 // FactTypes indicates that this analyzer imports and exports
62 // Facts of the specified concrete types.
63 // An analyzer that uses facts may assume that its import
64 // dependencies have been similarly analyzed before it runs.
65 // Facts must be pointers.
67 // FactTypes establishes a "vertical" dependency between
68 // analysis passes (same analyzer, different packages).
72 func (a *Analyzer) String() string { return a.Name }
75 // Set the analysisinternal functions to be able to pass type errors
76 // to the Pass type without modifying the go/analysis API.
77 analysisinternal.SetTypeErrors = func(p interface{}, errors []types.Error) {
78 p.(*Pass).typeErrors = errors
80 analysisinternal.GetTypeErrors = func(p interface{}) []types.Error {
81 return p.(*Pass).typeErrors
85 // A Pass provides information to the Run function that
86 // applies a specific analyzer to a single Go package.
88 // It forms the interface between the analysis logic and the driver
89 // program, and has both input and an output components.
91 // As in a compiler, one pass may depend on the result computed by another.
93 // The Run function should not call any of the Pass functions concurrently.
95 Analyzer *Analyzer // the identity of the current analyzer
97 // syntax and type information
98 Fset *token.FileSet // file position information
99 Files []*ast.File // the abstract syntax tree of each file
100 OtherFiles []string // names of non-Go files of this package
101 IgnoredFiles []string // names of ignored source files in this package
102 Pkg *types.Package // type information about the package
103 TypesInfo *types.Info // type information about the syntax trees
104 TypesSizes types.Sizes // function for computing sizes of types
106 // Report reports a Diagnostic, a finding about a specific location
107 // in the analyzed source code such as a potential mistake.
108 // It may be called by the Run function.
109 Report func(Diagnostic)
111 // ResultOf provides the inputs to this analysis pass, which are
112 // the corresponding results of its prerequisite analyzers.
113 // The map keys are the elements of Analysis.Required,
114 // and the type of each corresponding value is the required
115 // analysis's ResultType.
116 ResultOf map[*Analyzer]interface{}
120 // ImportObjectFact retrieves a fact associated with obj.
121 // Given a value ptr of type *T, where *T satisfies Fact,
122 // ImportObjectFact copies the value to *ptr.
124 // ImportObjectFact panics if called after the pass is complete.
125 // ImportObjectFact is not concurrency-safe.
126 ImportObjectFact func(obj types.Object, fact Fact) bool
128 // ImportPackageFact retrieves a fact associated with package pkg,
129 // which must be this package or one of its dependencies.
130 // See comments for ImportObjectFact.
131 ImportPackageFact func(pkg *types.Package, fact Fact) bool
133 // ExportObjectFact associates a fact of type *T with the obj,
134 // replacing any previous fact of that type.
136 // ExportObjectFact panics if it is called after the pass is
137 // complete, or if obj does not belong to the package being analyzed.
138 // ExportObjectFact is not concurrency-safe.
139 ExportObjectFact func(obj types.Object, fact Fact)
141 // ExportPackageFact associates a fact with the current package.
142 // See comments for ExportObjectFact.
143 ExportPackageFact func(fact Fact)
145 // AllPackageFacts returns a new slice containing all package facts of the analysis's FactTypes
146 // in unspecified order.
147 // WARNING: This is an experimental API and may change in the future.
148 AllPackageFacts func() []PackageFact
150 // AllObjectFacts returns a new slice containing all object facts of the analysis's FactTypes
151 // in unspecified order.
152 // WARNING: This is an experimental API and may change in the future.
153 AllObjectFacts func() []ObjectFact
155 // typeErrors contains types.Errors that are associated with the pkg.
156 typeErrors []types.Error
158 /* Further fields may be added in future. */
159 // For example, suggested or applied refactorings.
162 // PackageFact is a package together with an associated fact.
163 // WARNING: This is an experimental API and may change in the future.
164 type PackageFact struct {
165 Package *types.Package
169 // ObjectFact is an object together with an associated fact.
170 // WARNING: This is an experimental API and may change in the future.
171 type ObjectFact struct {
176 // Reportf is a helper function that reports a Diagnostic using the
177 // specified position and formatted error message.
178 func (pass *Pass) Reportf(pos token.Pos, format string, args ...interface{}) {
179 msg := fmt.Sprintf(format, args...)
180 pass.Report(Diagnostic{Pos: pos, Message: msg})
183 // The Range interface provides a range. It's equivalent to and satisfied by
185 type Range interface {
186 Pos() token.Pos // position of first character belonging to the node
187 End() token.Pos // position of first character immediately after the node
190 // ReportRangef is a helper function that reports a Diagnostic using the
191 // range provided. ast.Node values can be passed in as the range because
192 // they satisfy the Range interface.
193 func (pass *Pass) ReportRangef(rng Range, format string, args ...interface{}) {
194 msg := fmt.Sprintf(format, args...)
195 pass.Report(Diagnostic{Pos: rng.Pos(), End: rng.End(), Message: msg})
198 func (pass *Pass) String() string {
199 return fmt.Sprintf("%s@%s", pass.Analyzer.Name, pass.Pkg.Path())
202 // A Fact is an intermediate fact produced during analysis.
204 // Each fact is associated with a named declaration (a types.Object) or
205 // with a package as a whole. A single object or package may have
206 // multiple associated facts, but only one of any particular fact type.
208 // A Fact represents a predicate such as "never returns", but does not
209 // represent the subject of the predicate such as "function F" or "package P".
211 // Facts may be produced in one analysis pass and consumed by another
212 // analysis pass even if these are in different address spaces.
213 // If package P imports Q, all facts about Q produced during
214 // analysis of that package will be available during later analysis of P.
215 // Facts are analogous to type export data in a build system:
216 // just as export data enables separate compilation of several passes,
217 // facts enable "separate analysis".
219 // Each pass (a, p) starts with the set of facts produced by the
220 // same analyzer a applied to the packages directly imported by p.
221 // The analysis may add facts to the set, and they may be exported in turn.
222 // An analysis's Run function may retrieve facts by calling
223 // Pass.Import{Object,Package}Fact and update them using
224 // Pass.Export{Object,Package}Fact.
226 // A fact is logically private to its Analysis. To pass values
227 // between different analyzers, use the results mechanism;
228 // see Analyzer.Requires, Analyzer.ResultType, and Pass.ResultOf.
230 // A Fact type must be a pointer.
231 // Facts are encoded and decoded using encoding/gob.
232 // A Fact may implement the GobEncoder/GobDecoder interfaces
233 // to customize its encoding. Fact encoding should not fail.
235 // A Fact should not be modified once exported.
236 type Fact interface {
237 AFact() // dummy method to avoid type errors