pkg/terminal: Allow fuzzy searching tab completions (#2633)

This patch implements fuzzy searching for tab completions in the
terminal client. Under the hood it is using a trie data structure
(https://en.wikipedia.org/wiki/Trie) to perform very fast prefix / fuzzy
searches.

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/aquasecurity/libbpfgo v0.1.2-0.20210708203834-4928d36fafac
 	github.com/cosiner/argv v0.1.0
 	github.com/creack/pty v1.1.9
+	github.com/derekparker/trie v0.0.0-20200317170641-1fdf38b7b0e9
 	github.com/google/go-dap v0.5.0
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/mattn/go-colorable v0.0.9

go.sum

@@ -44,6 +44,8 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/derekparker/trie v0.0.0-20200317170641-1fdf38b7b0e9 h1:G765iDCq7bP5opdrPkXk+4V3yfkgV9iGFuheWZ/X/zY=
+github.com/derekparker/trie v0.0.0-20200317170641-1fdf38b7b0e9/go.mod h1:D6ICZm05D9VN1n/8iOtBxLpXtoGp6HDFUJ1RNVieOSE=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=

pkg/terminal/command.go

@@ -590,10 +590,10 @@ func (c *Commands) Register(cmdstr string, cf cmdfunc, helpMsg string) {
 // Find will look up the command function for the given command input.
 // If it cannot find the command it will default to noCmdAvailable().
 // If the command is an empty string it will replay the last command.
-func (c *Commands) Find(cmdstr string, prefix cmdPrefix) cmdfunc {
+func (c *Commands) Find(cmdstr string, prefix cmdPrefix) command {
 	// If <enter> use last command, if there was one.
 	if cmdstr == "" {
-		return nullCommand
+		return command{aliases: []string{"nullcmd"}, cmdFn: nullCommand}
 	}
 
 	for _, v := range c.cmds {
@@ -601,11 +601,11 @@ func (c *Commands) Find(cmdstr string, prefix cmdPrefix) cmdfunc {
 			if prefix != noPrefix && v.allowedPrefixes&prefix == 0 {
 				continue
 			}
-			return v.cmdFn
+			return v
 		}
 	}
 
-	return noCmdAvailable
+	return command{aliases: []string{"nocmd"}, cmdFn: noCmdAvailable}
 }
 
 // CallWithContext takes a command and a context that command should be executed in.
@@ -616,7 +616,7 @@ func (c *Commands) CallWithContext(cmdstr string, t *Term, ctx callContext) erro
 	if len(vals) > 1 {
 		args = strings.TrimSpace(vals[1])
 	}
-	return c.Find(cmdname, ctx.Prefix)(t, ctx, args)
+	return c.Find(cmdname, ctx.Prefix).cmdFn(t, ctx, args)
 }
 
 // Call takes a command to execute.

pkg/terminal/command_test.go

@@ -178,7 +178,7 @@ func withTestTerminalBuildFlags(name string, t testing.TB, buildFlags test.Build
 func TestCommandDefault(t *testing.T) {
 	var (
 		cmds = Commands{}
-		cmd  = cmds.Find("non-existant-command", noPrefix)
+		cmd  = cmds.Find("non-existant-command", noPrefix).cmdFn
 	)
 
 	err := cmd(nil, callContext{}, "")
@@ -194,7 +194,7 @@ func TestCommandDefault(t *testing.T) {
 func TestCommandReplayWithoutPreviousCommand(t *testing.T) {
 	var (
 		cmds = DebugCommands(nil)
-		cmd  = cmds.Find("", noPrefix)
+		cmd  = cmds.Find("", noPrefix).cmdFn
 		err  = cmd(nil, callContext{}, "")
 	)
 
@@ -206,7 +206,7 @@ func TestCommandReplayWithoutPreviousCommand(t *testing.T) {
 func TestCommandThread(t *testing.T) {
 	var (
 		cmds = DebugCommands(nil)
-		cmd  = cmds.Find("thread", noPrefix)
+		cmd  = cmds.Find("thread", noPrefix).cmdFn
 	)
 
 	err := cmd(nil, callContext{}, "")

pkg/terminal/terminal.go

@@ -10,6 +10,7 @@ import (
 	"sync"
 	"syscall"
 
+	"github.com/derekparker/trie"
 	"github.com/peterh/liner"
 
 	"github.com/go-delve/delve/pkg/config"
@@ -210,21 +211,32 @@ func (t *Term) Run() (int, error) {
 	signal.Notify(ch, syscall.SIGINT)
 	go t.sigintGuard(ch, multiClient)
 
-	t.line.SetCompleter(func(line string) (c []string) {
-		if strings.HasPrefix(line, "break ") || strings.HasPrefix(line, "b ") {
-			filter := line[strings.Index(line, " ")+1:]
-			funcs, _ := t.client.ListFunctions(filter)
-			for _, f := range funcs {
-				c = append(c, "break "+f)
-			}
-			return
+	fns := trie.New()
+	cmds := trie.New()
+	funcs, _ := t.client.ListFunctions("")
+	for _, fn := range funcs {
+		fns.Add(fn, nil)
+	}
+	for _, cmd := range t.cmds.cmds {
+		for _, alias := range cmd.aliases {
+			cmds.Add(alias, nil)
 		}
-		for _, cmd := range t.cmds.cmds {
-			for _, alias := range cmd.aliases {
-				if strings.HasPrefix(alias, strings.ToLower(line)) {
-					c = append(c, alias)
+	}
+
+	t.line.SetCompleter(func(line string) (c []string) {
+		cmd := t.cmds.Find(strings.Split(line, " ")[0], noPrefix)
+		switch cmd.aliases[0] {
+		case "break", "trace", "continue":
+			if spc := strings.LastIndex(line, " "); spc > 0 {
+				prefix := line[:spc] + " "
+				funcs := fns.FuzzySearch(line[spc+1:])
+				for _, f := range funcs {
+					c = append(c, prefix+f)
 				}
 			}
+		case "nullcmd", "nocmd":
+			commands := cmds.FuzzySearch(strings.ToLower(line))
+			c = append(c, commands...)
 		}
 		return
 	})

vendor/github.com/derekparker/trie/.deepsource.toml

@@ -0,0 +1,13 @@
+version = 1
+
+test_patterns = ["*_test.go"]
+
+exclude_patterns = ["vendor/*"]
+
+[[analyzers]]
+name = "go"
+enabled = true
+
+  [analyzers.meta]
+  import_path = "github.com/derekparker/trie"
+  dependencies_vendored = true

vendor/github.com/derekparker/trie/.gitignore

@@ -0,0 +1 @@
+*.test

vendor/github.com/derekparker/trie/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Derek Parker
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/derekparker/trie/README.md

@@ -0,0 +1,62 @@
+[![GoDoc](https://godoc.org/github.com/derekparker/trie?status.svg)](https://godoc.org/github.com/derekparker/trie)
+
+# Trie
+Data structure and relevant algorithms for extremely fast prefix/fuzzy string searching.
+
+## Usage
+
+Create a Trie with:
+
+```Go
+t := trie.New()
+```
+
+Add Keys with:
+
+```Go
+// Add can take in meta information which can be stored with the key.
+// i.e. you could store any information you would like to associate with
+// this particular key.
+t.Add("foobar", 1)
+```
+
+Find a key with:
+
+```Go
+node, ok := t.Find("foobar")
+meta := node.Meta()
+// use meta with meta.(type)
+```
+
+Remove Keys with:
+
+```Go
+t.Remove("foobar")
+```
+
+Prefix search with:
+
+```Go
+t.PrefixSearch("foo")
+```
+
+Fast test for valid prefix:
+```Go
+t.HasKeysWithPrefix("foo")
+```
+
+Fuzzy search with:
+
+```Go
+t.FuzzySearch("fb")
+```
+
+## Contributing
+Fork this repo and run tests with:
+
+	go test
+
+Create a feature branch, write your tests and code and submit a pull request.
+
+## License
+MIT

vendor/github.com/derekparker/trie/trie.go

@@ -0,0 +1,306 @@
+// Implementation of an R-Way Trie data structure.
+//
+// A Trie has a root Node which is the base of the tree.
+// Each subsequent Node has a letter and children, which are
+// nodes that have letter values associated with them.
+package trie
+
+import (
+	"sort"
+	"sync"
+)
+
+type Node struct {
+	val       rune
+	path      string
+	term      bool
+	depth     int
+	meta      interface{}
+	mask      uint64
+	parent    *Node
+	children  map[rune]*Node
+	termCount int
+}
+
+type Trie struct {
+	mu   sync.Mutex
+	root *Node
+	size int
+}
+
+type ByKeys []string
+
+func (a ByKeys) Len() int           { return len(a) }
+func (a ByKeys) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a ByKeys) Less(i, j int) bool { return len(a[i]) < len(a[j]) }
+
+const nul = 0x0
+
+// Creates a new Trie with an initialized root Node.
+func New() *Trie {
+	return &Trie{
+		root: &Node{children: make(map[rune]*Node), depth: 0},
+		size: 0,
+	}
+}
+
+// Returns the root node for the Trie.
+func (t *Trie) Root() *Node {
+	return t.root
+}
+
+// Adds the key to the Trie, including meta data. Meta data
+// is stored as `interface{}` and must be type cast by
+// the caller.
+func (t *Trie) Add(key string, meta interface{}) *Node {
+	t.mu.Lock()
+
+	t.size++
+	runes := []rune(key)
+	bitmask := maskruneslice(runes)
+	node := t.root
+	node.mask |= bitmask
+	node.termCount++
+	for i := range runes {
+		r := runes[i]
+		bitmask = maskruneslice(runes[i:])
+		if n, ok := node.children[r]; ok {
+			node = n
+			node.mask |= bitmask
+		} else {
+			node = node.NewChild(r, "", bitmask, nil, false)
+		}
+		node.termCount++
+	}
+	node = node.NewChild(nul, key, 0, meta, true)
+	t.mu.Unlock()
+
+	return node
+}
+
+// Finds and returns meta data associated
+// with `key`.
+func (t *Trie) Find(key string) (*Node, bool) {
+	node := findNode(t.Root(), []rune(key))
+	if node == nil {
+		return nil, false
+	}
+
+	node, ok := node.Children()[nul]
+	if !ok || !node.term {
+		return nil, false
+	}
+
+	return node, true
+}
+
+func (t *Trie) HasKeysWithPrefix(key string) bool {
+	node := findNode(t.Root(), []rune(key))
+	return node != nil
+}
+
+// Removes a key from the trie, ensuring that
+// all bitmasks up to root are appropriately recalculated.
+func (t *Trie) Remove(key string) {
+	var (
+		i    int
+		rs   = []rune(key)
+		node = findNode(t.Root(), []rune(key))
+	)
+	t.mu.Lock()
+
+	t.size--
+	for n := node.Parent(); n != nil; n = n.Parent() {
+		i++
+		if len(n.Children()) > 1 {
+			r := rs[len(rs)-i]
+			n.RemoveChild(r)
+			break
+		}
+	}
+	t.mu.Unlock()
+}
+
+// Returns all the keys currently stored in the trie.
+func (t *Trie) Keys() []string {
+	if t.size == 0 {
+		return []string{}
+	}
+
+	return t.PrefixSearch("")
+}
+
+// Performs a fuzzy search against the keys in the trie.
+func (t Trie) FuzzySearch(pre string) []string {
+	keys := fuzzycollect(t.Root(), []rune(pre))
+	sort.Sort(ByKeys(keys))
+	return keys
+}
+
+// Performs a prefix search against the keys in the trie.
+func (t Trie) PrefixSearch(pre string) []string {
+	node := findNode(t.Root(), []rune(pre))
+	if node == nil {
+		return nil
+	}
+
+	return collect(node)
+}
+
+// Creates and returns a pointer to a new child for the node.
+func (parent *Node) NewChild(val rune, path string, bitmask uint64, meta interface{}, term bool) *Node {
+	node := &Node{
+		val:      val,
+		path:     path,
+		mask:     bitmask,
+		term:     term,
+		meta:     meta,
+		parent:   parent,
+		children: make(map[rune]*Node),
+		depth:    parent.depth + 1,
+	}
+	parent.children[node.val] = node
+	parent.mask |= bitmask
+	return node
+}
+
+func (n *Node) RemoveChild(r rune) {
+	delete(n.children, r)
+	for nd := n.parent; nd != nil; nd = nd.parent {
+		nd.mask ^= nd.mask
+		nd.mask |= uint64(1) << uint64(nd.val-'a')
+		for _, c := range nd.children {
+			nd.mask |= c.mask
+		}
+	}
+}
+
+// Returns the parent of this node.
+func (n Node) Parent() *Node {
+	return n.parent
+}
+
+// Returns the meta information of this node.
+func (n Node) Meta() interface{} {
+	return n.meta
+}
+
+// Returns the children of this node.
+func (n Node) Children() map[rune]*Node {
+	return n.children
+}
+
+func (n Node) Terminating() bool {
+	return n.term
+}
+
+func (n Node) Val() rune {
+	return n.val
+}
+
+func (n Node) Depth() int {
+	return n.depth
+}
+
+// Returns a uint64 representing the current
+// mask of this node.
+func (n Node) Mask() uint64 {
+	return n.mask
+}
+
+func findNode(node *Node, runes []rune) *Node {
+	if node == nil {
+		return nil
+	}
+
+	if len(runes) == 0 {
+		return node
+	}
+
+	n, ok := node.Children()[runes[0]]
+	if !ok {
+		return nil
+	}
+
+	var nrunes []rune
+	if len(runes) > 1 {
+		nrunes = runes[1:]
+	} else {
+		nrunes = runes[0:0]
+	}
+
+	return findNode(n, nrunes)
+}
+
+func maskruneslice(rs []rune) uint64 {
+	var m uint64
+	for _, r := range rs {
+		m |= uint64(1) << uint64(r-'a')
+	}
+	return m
+}
+
+func collect(node *Node) []string {
+	var (
+		n *Node
+		i int
+	)
+	keys := make([]string, 0, node.termCount)
+	nodes := make([]*Node, 1, len(node.children))
+	nodes[0] = node
+	for l := len(nodes); l != 0; l = len(nodes) {
+		i = l - 1
+		n = nodes[i]
+		nodes = nodes[:i]
+		for _, c := range n.children {
+			nodes = append(nodes, c)
+		}
+		if n.term {
+			word := n.path
+			keys = append(keys, word)
+		}
+	}
+	return keys
+}
+
+type potentialSubtree struct {
+	idx  int
+	node *Node
+}
+
+func fuzzycollect(node *Node, partial []rune) []string {
+	if len(partial) == 0 {
+		return collect(node)
+	}
+
+	var (
+		m    uint64
+		i    int
+		p    potentialSubtree
+		keys []string
+	)
+
+	potential := []potentialSubtree{potentialSubtree{node: node, idx: 0}}
+	for l := len(potential); l > 0; l = len(potential) {
+		i = l - 1
+		p = potential[i]
+		potential = potential[:i]
+		m = maskruneslice(partial[p.idx:])
+		if (p.node.mask & m) != m {
+			continue
+		}
+
+		if p.node.val == partial[p.idx] {
+			p.idx++
+			if p.idx == len(partial) {
+				keys = append(keys, collect(p.node)...)
+				continue
+			}
+		}
+
+		for _, c := range p.node.children {
+			potential = append(potential, potentialSubtree{node: c, idx: p.idx})
+		}
+	}
+	return keys
+}

vendor/modules.txt

@@ -10,6 +10,8 @@ github.com/cpuguy83/go-md2man/v2/md2man
 # github.com/creack/pty v1.1.9
 ## explicit
 github.com/creack/pty
+# github.com/derekparker/trie v0.0.0-20200317170641-1fdf38b7b0e9
+github.com/derekparker/trie
 # github.com/google/go-dap v0.5.0
 ## explicit
 github.com/google/go-dap