internal/frontend/symbol.go - pkgsite - Git at Google

 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package frontend

 import (
 	"fmt"
 	"sort"
 	"strings"

 	"golang.org/x/pkgsite/internal"
 	"golang.org/x/pkgsite/internal/stdlib"
 )

 // Symbol is an element in the package API. A symbol can be a constant,
 // variable, function, type, field or method.
 type Symbol struct {
 	// Name is name of the symbol. At a given package version, name must be
 	// unique.
 	Name string

 	// Synopsis is the one line description of the symbol that is displayed.
 	Synopsis string

 	// Section is the section that a symbol appears in.
 	Section internal.SymbolSection

 	// Kind is the type of a symbol, which is either a constant, variable,
 	// function, type, field or method.
 	Kind internal.SymbolKind

 	// Link is the link to the symbol name on pkg.go.dev.
 	Link string

 	// Children contain the child symbols for this symbol. This will
 	// only be populated when the SymbolType is "Type". For example, the
 	// children of net/http.Handler are FileServer, NotFoundHandler,
 	// RedirectHandler, StripPrefix, and TimeoutHandler. Each child
 	// symbol will have ParentName set to the Name of this type.
 	Children []*Symbol

 	// Builds lists all of the build contexts supported by the symbol, it is
 	// only available for limited set of builds. If the symbol supports all
 	// build contexts, Builds will be nil.
 	Builds []string

 	// builds keeps track of build contexts used to generate Builds.
 	builds map[internal.BuildContext]bool

 	// New indicates that the symbol is new as of the version where it is
 	// present. For example, if type Client was introduced in v1.0.0 and
 	// Client.Timeout was introduced in v1.1.0, New will be false for Client
 	// and true for Client.Timeout if this Symbol corresponds to v1.1.0.
 	New bool
 }

 func (s *Symbol) addBuilds(builds ...internal.BuildContext) {
 	if s.builds == nil {
 		s.builds = map[internal.BuildContext]bool{}
 	}
 	for _, b := range builds {
 		s.builds[b] = true
 	}
 }

 // symbolsForVersions returns an array of symbols for use in the VersionSummary
 // of the specified version.
 func symbolsForVersion(pkgURLPath string, symbolsAtVersion map[string]map[internal.SymbolMeta]*internal.SymbolBuildContexts) [][]*Symbol {
 	nameToMetaToSymbol := map[string]map[internal.SymbolMeta]*Symbol{}
 	children := map[internal.SymbolMeta]*internal.SymbolBuildContexts{}
 	for _, smToUs := range symbolsAtVersion {
 		for sm, us := range smToUs {
 			if sm.ParentName != sm.Name {
 				// For the children, keep track of them for later.
 				children[sm] = us
 				continue
 			}

 			metaToSym, ok := nameToMetaToSymbol[sm.Name]
 			if !ok {
 				metaToSym = map[internal.SymbolMeta]*Symbol{}
 				nameToMetaToSymbol[sm.Name] = metaToSym
 			}
 			s, ok := metaToSym[sm]
 			if !ok {
 				s = &Symbol{
 					Name:     sm.Name,
 					Synopsis: sm.Synopsis,
 					Section:  sm.Section,
 					Kind:     sm.Kind,
 					Link:     symbolLink(pkgURLPath, sm.Name, us.BuildContexts()),
 					New:      true,
 				}
 				nameToMetaToSymbol[s.Name][sm] = s
 			}
 			s.addBuilds(us.BuildContexts()...)
 		}
 	}

 	for cm, cus := range children {
 		// For each child symbol, 1 of 3 things can occur:
 		//
 		// Option 1: If no parent exists for this child symbol, make one
 		// and add the parent to the map.
 		//
 		// Option 2: A parent exists and does not support the build context
 		// of the child. This occurs when the parent type is introduced for
 		// another build context, but was introduced at the previous version
 		// for the current child. Create a new parent for this child.
 		//
 		// Option 3: A parent exists and does support the build context of
 		// the child. Add the child to the parent.
 		cs := &Symbol{
 			Name:     cm.Name,
 			Synopsis: cm.Synopsis,
 			Section:  cm.Section,
 			Kind:     cm.Kind,
 			Link:     symbolLink(pkgURLPath, cm.Name, cus.BuildContexts()),
 			New:      true,
 		}

 		ps := findParent(cm.ParentName, cus, nameToMetaToSymbol)
 		if ps != nil {
 			// Option 3: found a relevant parent.
 			ps.Children = append(ps.Children, cs)
 			continue
 		}

 		// Option 1 and 2: We did not find a relevant parent, so create
 		// one.
 		//
 		// Since this parent is not introduced at this version, create
 		// a distinct type for each group of symbols.
 		// To do so, we make up a synopsis for the SymbolMeta below, since it
 		// is only used as a key in nameToMetaToSymbol.
 		//
 		// Example case:
 		// http://pkg.go.dev/internal/poll?tab=versions for go1.10 should show:
 		//
 		// type FD -- windows/amd64
 		//		FD.ReadMsg
 		//		FD.WriteMsg
 		// type FD -- darwin/amd64, linux/amd64
 		//		FD.SetBlocking
 		//		FD.WriteOnce
 		ps = createParent(cm.ParentName, pkgURLPath, cus.BuildContexts()...)
 		pm := internal.SymbolMeta{
 			Name:       ps.Name,
 			ParentName: ps.Name,
 			Synopsis:   fmt.Sprintf("type %s (%v)", ps.Name, cus.BuildContexts()),
 			Section:    ps.Section,
 			Kind:       ps.Kind,
 		}
 		ps.Children = append(ps.Children, cs)
 		if _, ok := nameToMetaToSymbol[pm.Name]; !ok {
 			nameToMetaToSymbol[pm.Name] = map[internal.SymbolMeta]*Symbol{}
 		}
 		nameToMetaToSymbol[pm.Name][pm] = ps
 	}

 	var symbols []*Symbol
 	for _, mts := range nameToMetaToSymbol {
 		for _, s := range mts {
 			if len(s.builds) != len(internal.BuildContexts) {
 				for b := range s.builds {
 					s.Builds = append(s.Builds, fmt.Sprintf("%s/%s", b.GOOS, b.GOARCH))
 				}
 				sort.Strings(s.Builds)
 			}
 			symbols = append(symbols, s)
 		}
 	}
 	return sortSymbols(symbols)
 }

 func findParent(parentName string, cus *internal.SymbolBuildContexts,
 	nameToMetaToSymbol map[string]map[internal.SymbolMeta]*Symbol) *Symbol {
 	parents, ok := nameToMetaToSymbol[parentName]
 	if !ok {
 		return nil
 	}
 	for _, ps := range parents {
 		for build := range ps.builds {
 			if cus.SupportsBuild(build) {
 				return ps
 			}
 		}
 	}
 	return nil
 }

 func symbolLink(pkgURLPath, name string, builds []internal.BuildContext) string {
 	if len(builds) == len(internal.BuildContexts) {
 		return fmt.Sprintf("%s#%s", pkgURLPath, name)
 	}

 	// When a symbol is introduced for a specific GOOS/GOARCH at a version,
 	// linking to an unspecified GOOS/GOARCH page might not take the user to
 	// the symbol. Instead, link to one of the supported build contexts.
 	return fmt.Sprintf("%s?GOOS=%s#%s", pkgURLPath, builds[0].GOOS, name)
 }

 // createParent creates a parent symbol for the provided unit symbol. This is
 // used when us is a child of a symbol that may have been introduced at a
 // different version. The symbol created will have New set to false, since this
 // function is only used when a parent symbol is not found for the unit symbol,
 // which means it was not introduced at the same version.
 func createParent(parentName, pkgURLPath string, builds ...internal.BuildContext) *Symbol {
 	s := &Symbol{
 		Name:     parentName,
 		Synopsis: fmt.Sprintf("type %s", parentName),
 		Section:  internal.SymbolSectionTypes,
 		Kind:     internal.SymbolKindType,
 		Link:     symbolLink(pkgURLPath, parentName, builds),
 	}
 	s.addBuilds(builds...)
 	return s
 }

 // sortSymbols returns an array of symbols in order of
 // (1) Constants (2) Variables (3) Functions and (4) Types.
 // Within each section, symbols are sorted alphabetically by name.
 // In the types sections, aside from interfaces, child symbols are sorted in
 // order of (1) Fields (2) Constants (3) Variables (4) Functions and (5)
 // Methods. For interfaces, child symbols are sorted in order of
 // (1) Methods (2) Constants (3) Variables and (4) Functions.
 func sortSymbols(symbols []*Symbol) [][]*Symbol {
 	sm := map[internal.SymbolSection][]*Symbol{}
 	for _, parent := range symbols {
 		sm[parent.Section] = append(sm[parent.Section], parent)
 		cm := map[internal.SymbolKind][]*Symbol{}
 		parent.Synopsis = strings.TrimSuffix(strings.TrimSuffix(parent.Synopsis, "{ ... }"), "{}")
 		for _, c := range parent.Children {
 			cm[c.Kind] = append(cm[c.Kind], c)
 		}
 		for _, syms := range cm {
 			sortSymbolsGroup(syms)
 		}
 		symbols := append(append(append(
 			cm[internal.SymbolKindField],
 			cm[internal.SymbolKindConstant]...),
 			cm[internal.SymbolKindVariable]...),
 			cm[internal.SymbolKindFunction]...)
 		if strings.Contains(parent.Synopsis, "interface") {
 			parent.Children = append(cm[internal.SymbolKindMethod], symbols...)
 		} else {
 			parent.Children = append(symbols, cm[internal.SymbolKindMethod]...)
 		}
 	}
 	for _, syms := range sm {
 		sortSymbolsGroup(syms)
 	}

 	var out [][]*Symbol
 	for _, section := range []internal.SymbolSection{
 		internal.SymbolSectionConstants,
 		internal.SymbolSectionVariables,
 		internal.SymbolSectionFunctions,
 		internal.SymbolSectionTypes} {
 		if sm[section] != nil {
 			out = append(out, sm[section])
 		}
 	}
 	return out
 }

 func sortSymbolsGroup(syms []*Symbol) {
 	sort.Slice(syms, func(i, j int) bool {
 		s1 := syms[i]
 		s2 := syms[j]
 		if s1.Synopsis != s2.Synopsis {
 			return s1.Synopsis < s2.Synopsis
 		}
 		return compareStringSlices(s1.Builds, s2.Builds) < 0
 	})
 }

 func compareStringSlices(ss1, ss2 []string) int {
 	for i, s1 := range ss1 {
 		if i >= len(ss2) { // first slice is longer, so greater
 			return 1
 		}
 		if c := strings.Compare(s1, ss2[i]); c != 0 {
 			return c
 		}
 	}
 	if len(ss1) == len(ss2) {
 		return 0
 	}
 	// first slice is shorter
 	return -1
 }

 // ParseVersionsDetails returns a map of versionToNameToUnitSymbol based on
 // data from the proovided VersionDetails.
 func ParseVersionsDetails(vd *VersionsDetails) (_ *internal.SymbolHistory, err error) {
 	sh := internal.NewSymbolHistory()
 	for _, vl := range vd.ThisModule {
 		for _, vs := range vl.Versions {
 			v := vs.Version
 			if vd.ThisModule[0].ModulePath == stdlib.ModulePath {
 				v = stdlib.VersionForTag(v)
 			}
 			for _, syms := range vs.Symbols {
 				for _, s := range syms {
 					if s.New {
 						addSymbol(s, v, sh, s.Builds)
 					}
 					for _, c := range s.Children {
 						addSymbol(c, v, sh, s.Builds)
 					}
 				}
 			}
 		}
 	}
 	return sh, nil
 }

 func addSymbol(s *Symbol, v string, sh *internal.SymbolHistory, builds []string) {
 	sm := internal.SymbolMeta{
 		Name: s.Name,
 	}
 	if len(builds) == 0 {
 		sh.AddSymbol(sm, v, internal.BuildContextAll)
 		return
 	}
 	for _, b := range builds {
 		parts := strings.SplitN(b, "/", 2)
 		var build internal.BuildContext
 		switch parts[0] {
 		case "linux":
 			build = internal.BuildContextLinux
 		case "darwin":
 			build = internal.BuildContextDarwin
 		case "windows":
 			build = internal.BuildContextWindows
 		case "js":
 			build = internal.BuildContextJS
 		}
 		sh.AddSymbol(sm, v, build)
 	}
 }
	// Copyright 2021 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package frontend

	import (
	"fmt"
	"sort"
	"strings"

	"golang.org/x/pkgsite/internal"
	"golang.org/x/pkgsite/internal/stdlib"
	)

	// Symbol is an element in the package API. A symbol can be a constant,
	// variable, function, type, field or method.
	type Symbol struct {
	// Name is name of the symbol. At a given package version, name must be
	// unique.
	Name string

	// Synopsis is the one line description of the symbol that is displayed.
	Synopsis string

	// Section is the section that a symbol appears in.
	Section internal.SymbolSection

	// Kind is the type of a symbol, which is either a constant, variable,
	// function, type, field or method.
	Kind internal.SymbolKind

	// Link is the link to the symbol name on pkg.go.dev.
	Link string

	// Children contain the child symbols for this symbol. This will
	// only be populated when the SymbolType is "Type". For example, the
	// children of net/http.Handler are FileServer, NotFoundHandler,
	// RedirectHandler, StripPrefix, and TimeoutHandler. Each child
	// symbol will have ParentName set to the Name of this type.
	Children []*Symbol

	// Builds lists all of the build contexts supported by the symbol, it is
	// only available for limited set of builds. If the symbol supports all
	// build contexts, Builds will be nil.
	Builds []string

	// builds keeps track of build contexts used to generate Builds.
	builds map[internal.BuildContext]bool

	// New indicates that the symbol is new as of the version where it is
	// present. For example, if type Client was introduced in v1.0.0 and
	// Client.Timeout was introduced in v1.1.0, New will be false for Client
	// and true for Client.Timeout if this Symbol corresponds to v1.1.0.
	New bool
	}

	func (s *Symbol) addBuilds(builds ...internal.BuildContext) {
	if s.builds == nil {
	s.builds = map[internal.BuildContext]bool{}
	}
	for _, b := range builds {
	s.builds[b] = true
	}
	}

	// symbolsForVersions returns an array of symbols for use in the VersionSummary
	// of the specified version.
	func symbolsForVersion(pkgURLPath string, symbolsAtVersion map[string]map[internal.SymbolMeta]internal.SymbolBuildContexts) [][]Symbol {
	nameToMetaToSymbol := map[string]map[internal.SymbolMeta]*Symbol{}
	children := map[internal.SymbolMeta]*internal.SymbolBuildContexts{}
	for _, smToUs := range symbolsAtVersion {
	for sm, us := range smToUs {
	if sm.ParentName != sm.Name {
	// For the children, keep track of them for later.
	children[sm] = us
	continue
	}

	metaToSym, ok := nameToMetaToSymbol[sm.Name]
	if !ok {
	metaToSym = map[internal.SymbolMeta]*Symbol{}
	nameToMetaToSymbol[sm.Name] = metaToSym
	}
	s, ok := metaToSym[sm]
	if !ok {
	s = &Symbol{
	Name: sm.Name,
	Synopsis: sm.Synopsis,
	Section: sm.Section,
	Kind: sm.Kind,
	Link: symbolLink(pkgURLPath, sm.Name, us.BuildContexts()),
	New: true,
	}
	nameToMetaToSymbol[s.Name][sm] = s
	}
	s.addBuilds(us.BuildContexts()...)
	}
	}

	for cm, cus := range children {
	// For each child symbol, 1 of 3 things can occur:
	//
	// Option 1: If no parent exists for this child symbol, make one
	// and add the parent to the map.
	//
	// Option 2: A parent exists and does not support the build context
	// of the child. This occurs when the parent type is introduced for
	// another build context, but was introduced at the previous version
	// for the current child. Create a new parent for this child.
	//
	// Option 3: A parent exists and does support the build context of
	// the child. Add the child to the parent.
	cs := &Symbol{
	Name: cm.Name,
	Synopsis: cm.Synopsis,
	Section: cm.Section,
	Kind: cm.Kind,
	Link: symbolLink(pkgURLPath, cm.Name, cus.BuildContexts()),
	New: true,
	}

	ps := findParent(cm.ParentName, cus, nameToMetaToSymbol)
	if ps != nil {
	// Option 3: found a relevant parent.
	ps.Children = append(ps.Children, cs)
	continue
	}

	// Option 1 and 2: We did not find a relevant parent, so create
	// one.
	//
	// Since this parent is not introduced at this version, create
	// a distinct type for each group of symbols.
	// To do so, we make up a synopsis for the SymbolMeta below, since it
	// is only used as a key in nameToMetaToSymbol.
	//
	// Example case:
	// http://pkg.go.dev/internal/poll?tab=versions for go1.10 should show:
	//
	// type FD -- windows/amd64
	// FD.ReadMsg
	// FD.WriteMsg
	// type FD -- darwin/amd64, linux/amd64
	// FD.SetBlocking
	// FD.WriteOnce
	ps = createParent(cm.ParentName, pkgURLPath, cus.BuildContexts()...)
	pm := internal.SymbolMeta{
	Name: ps.Name,
	ParentName: ps.Name,
	Synopsis: fmt.Sprintf("type %s (%v)", ps.Name, cus.BuildContexts()),
	Section: ps.Section,
	Kind: ps.Kind,
	}
	ps.Children = append(ps.Children, cs)
	if _, ok := nameToMetaToSymbol[pm.Name]; !ok {
	nameToMetaToSymbol[pm.Name] = map[internal.SymbolMeta]*Symbol{}
	}
	nameToMetaToSymbol[pm.Name][pm] = ps
	}

	var symbols []*Symbol
	for _, mts := range nameToMetaToSymbol {
	for _, s := range mts {
	if len(s.builds) != len(internal.BuildContexts) {
	for b := range s.builds {
	s.Builds = append(s.Builds, fmt.Sprintf("%s/%s", b.GOOS, b.GOARCH))
	}
	sort.Strings(s.Builds)
	}
	symbols = append(symbols, s)
	}
	}
	return sortSymbols(symbols)
	}

	func findParent(parentName string, cus *internal.SymbolBuildContexts,
	nameToMetaToSymbol map[string]map[internal.SymbolMeta]Symbol) Symbol {
	parents, ok := nameToMetaToSymbol[parentName]
	if !ok {
	return nil
	}
	for _, ps := range parents {
	for build := range ps.builds {
	if cus.SupportsBuild(build) {
	return ps
	}
	}
	}
	return nil
	}

	func symbolLink(pkgURLPath, name string, builds []internal.BuildContext) string {
	if len(builds) == len(internal.BuildContexts) {
	return fmt.Sprintf("%s#%s", pkgURLPath, name)
	}

	// When a symbol is introduced for a specific GOOS/GOARCH at a version,
	// linking to an unspecified GOOS/GOARCH page might not take the user to
	// the symbol. Instead, link to one of the supported build contexts.
	return fmt.Sprintf("%s?GOOS=%s#%s", pkgURLPath, builds[0].GOOS, name)
	}

	// createParent creates a parent symbol for the provided unit symbol. This is
	// used when us is a child of a symbol that may have been introduced at a
	// different version. The symbol created will have New set to false, since this
	// function is only used when a parent symbol is not found for the unit symbol,
	// which means it was not introduced at the same version.
	func createParent(parentName, pkgURLPath string, builds ...internal.BuildContext) *Symbol {
	s := &Symbol{
	Name: parentName,
	Synopsis: fmt.Sprintf("type %s", parentName),
	Section: internal.SymbolSectionTypes,
	Kind: internal.SymbolKindType,
	Link: symbolLink(pkgURLPath, parentName, builds),
	}
	s.addBuilds(builds...)
	return s
	}

	// sortSymbols returns an array of symbols in order of
	// (1) Constants (2) Variables (3) Functions and (4) Types.
	// Within each section, symbols are sorted alphabetically by name.
	// In the types sections, aside from interfaces, child symbols are sorted in
	// order of (1) Fields (2) Constants (3) Variables (4) Functions and (5)
	// Methods. For interfaces, child symbols are sorted in order of
	// (1) Methods (2) Constants (3) Variables and (4) Functions.
	func sortSymbols(symbols []Symbol) [][]Symbol {
	sm := map[internal.SymbolSection][]*Symbol{}
	for _, parent := range symbols {
	sm[parent.Section] = append(sm[parent.Section], parent)
	cm := map[internal.SymbolKind][]*Symbol{}
	parent.Synopsis = strings.TrimSuffix(strings.TrimSuffix(parent.Synopsis, "{ ... }"), "{}")
	for _, c := range parent.Children {
	cm[c.Kind] = append(cm[c.Kind], c)
	}
	for _, syms := range cm {
	sortSymbolsGroup(syms)
	}
	symbols := append(append(append(
	cm[internal.SymbolKindField],
	cm[internal.SymbolKindConstant]...),
	cm[internal.SymbolKindVariable]...),
	cm[internal.SymbolKindFunction]...)
	if strings.Contains(parent.Synopsis, "interface") {
	parent.Children = append(cm[internal.SymbolKindMethod], symbols...)
	} else {
	parent.Children = append(symbols, cm[internal.SymbolKindMethod]...)
	}
	}
	for _, syms := range sm {
	sortSymbolsGroup(syms)
	}

	var out [][]*Symbol
	for _, section := range []internal.SymbolSection{
	internal.SymbolSectionConstants,
	internal.SymbolSectionVariables,
	internal.SymbolSectionFunctions,
	internal.SymbolSectionTypes} {
	if sm[section] != nil {
	out = append(out, sm[section])
	}
	}
	return out
	}

	func sortSymbolsGroup(syms []*Symbol) {
	sort.Slice(syms, func(i, j int) bool {
	s1 := syms[i]
	s2 := syms[j]
	if s1.Synopsis != s2.Synopsis {
	return s1.Synopsis < s2.Synopsis
	}
	return compareStringSlices(s1.Builds, s2.Builds) < 0
	})
	}

	func compareStringSlices(ss1, ss2 []string) int {
	for i, s1 := range ss1 {
	if i >= len(ss2) { // first slice is longer, so greater
	return 1
	}
	if c := strings.Compare(s1, ss2[i]); c != 0 {
	return c
	}
	}
	if len(ss1) == len(ss2) {
	return 0
	}
	// first slice is shorter
	return -1
	}

	// ParseVersionsDetails returns a map of versionToNameToUnitSymbol based on
	// data from the proovided VersionDetails.
	func ParseVersionsDetails(vd VersionsDetails) (_ internal.SymbolHistory, err error) {
	sh := internal.NewSymbolHistory()
	for _, vl := range vd.ThisModule {
	for _, vs := range vl.Versions {
	v := vs.Version
	if vd.ThisModule[0].ModulePath == stdlib.ModulePath {
	v = stdlib.VersionForTag(v)
	}
	for _, syms := range vs.Symbols {
	for _, s := range syms {
	if s.New {
	addSymbol(s, v, sh, s.Builds)
	}
	for _, c := range s.Children {
	addSymbol(c, v, sh, s.Builds)
	}
	}
	}
	}
	}
	return sh, nil
	}

	func addSymbol(s Symbol, v string, sh internal.SymbolHistory, builds []string) {
	sm := internal.SymbolMeta{
	Name: s.Name,
	}
	if len(builds) == 0 {
	sh.AddSymbol(sm, v, internal.BuildContextAll)
	return
	}
	for _, b := range builds {
	parts := strings.SplitN(b, "/", 2)
	var build internal.BuildContext
	switch parts[0] {
	case "linux":
	build = internal.BuildContextLinux
	case "darwin":
	build = internal.BuildContextDarwin
	case "windows":
	build = internal.BuildContextWindows
	case "js":
	build = internal.BuildContextJS
	}
	sh.AddSymbol(sm, v, build)
	}
	}