forked from ebhomengo/niki
130 lines
3.3 KiB
Go
130 lines
3.3 KiB
Go
// Package depth provides the ability to traverse and retrieve Go source code dependencies in the form of
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// internal and external packages.
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//
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// For example, the dependencies of the stdlib `strings` package can be resolved like so:
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//
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// import "github.com/KyleBanks/depth"
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//
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// var t depth.Tree
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// err := t.Resolve("strings")
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// if err != nil {
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// log.Fatal(err)
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// }
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//
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// // Output: "strings has 4 dependencies."
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// log.Printf("%v has %v dependencies.", t.Root.Name, len(t.Root.Deps))
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//
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// For additional customization, simply set the appropriate flags on the `Tree` before resolving:
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//
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// import "github.com/KyleBanks/depth"
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//
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// t := depth.Tree {
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// ResolveInternal: true,
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// ResolveTest: true,
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// MaxDepth: 10,
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// }
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// err := t.Resolve("strings")
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package depth
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import (
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"errors"
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"go/build"
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"os"
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)
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// ErrRootPkgNotResolved is returned when the root Pkg of the Tree cannot be resolved,
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// typically because it does not exist.
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var ErrRootPkgNotResolved = errors.New("unable to resolve root package")
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// Importer defines a type that can import a package and return its details.
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type Importer interface {
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Import(name, srcDir string, im build.ImportMode) (*build.Package, error)
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}
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// Tree represents the top level of a Pkg and the configuration used to
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// initialize and represent its contents.
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type Tree struct {
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Root *Pkg
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ResolveInternal bool
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ResolveTest bool
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MaxDepth int
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Importer Importer
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importCache map[string]struct{}
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}
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// Resolve recursively finds all dependencies for the root Pkg name provided,
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// and the packages it depends on.
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func (t *Tree) Resolve(name string) error {
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pwd, err := os.Getwd()
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if err != nil {
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return err
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}
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t.Root = &Pkg{
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Name: name,
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Tree: t,
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SrcDir: pwd,
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Test: false,
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}
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// Reset the import cache each time to ensure a reused Tree doesn't
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// reuse the same cache.
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t.importCache = nil
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// Allow custom importers, but use build.Default if none is provided.
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if t.Importer == nil {
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t.Importer = &build.Default
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}
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t.Root.Resolve(t.Importer)
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if !t.Root.Resolved {
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return ErrRootPkgNotResolved
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}
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return nil
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}
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// shouldResolveInternal determines if internal packages should be further resolved beyond the
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// current parent.
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//
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// For example, if the parent Pkg is `github.com/foo/bar` and true is returned, all the
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// internal dependencies it relies on will be resolved. If for example `strings` is one of those
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// dependencies, and it is passed as the parent here, false may be returned and its internal
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// dependencies will not be resolved.
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func (t *Tree) shouldResolveInternal(parent *Pkg) bool {
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if t.ResolveInternal {
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return true
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}
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return parent == t.Root
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}
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// isAtMaxDepth returns true when the depth of the Pkg provided is at or beyond the maximum
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// depth allowed by the tree.
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//
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// If the Tree has a MaxDepth of zero, true is never returned.
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func (t *Tree) isAtMaxDepth(p *Pkg) bool {
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if t.MaxDepth == 0 {
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return false
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}
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return p.depth() >= t.MaxDepth
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}
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// hasSeenImport returns true if the import name provided has already been seen within the tree.
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// This function only returns false for a name once.
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func (t *Tree) hasSeenImport(name string) bool {
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if t.importCache == nil {
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t.importCache = make(map[string]struct{})
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}
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if _, ok := t.importCache[name]; ok {
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return true
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}
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t.importCache[name] = struct{}{}
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return false
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}
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