feat(hosts): Add resolver analyzation

doc-values/extra-values.go

@@ -3,6 +3,7 @@ package docvalues
 import (
 	"config-lsp/utils"
 	"os"
+	"regexp"
 	"strings"
 )
 
@@ -173,3 +174,9 @@ func SingleEnumValue(value string) EnumValue {
 		},
 	}
 }
+
+func DomainValue() Value {
+	return RegexValue{
+		Regex: *regexp.MustCompile(`^.+?\..+$`),
+	}
+}

handlers/hosts/fields/documentation-fields.go

@@ -0,0 +1,10 @@
+package fields
+
+import docvalues "config-lsp/doc-values"
+
+var IPAddressField = docvalues.IPAddressValue{
+	AllowIPv4: true,
+	AllowIPv6: true,
+}
+
+var HostnameField = docvalues.DomainValue()

handlers/hosts/handlers/analyzer.go

@@ -0,0 +1,93 @@
+package handlers
+
+import (
+	"config-lsp/common"
+	"config-lsp/handlers/hosts/tree"
+	"config-lsp/utils"
+	"net"
+)
+
+type ResolverEntry struct {
+	IPv4Address net.IP
+	IPv6Address net.IP
+	Line        uint32
+}
+
+type Resolver struct {
+	Entries map[string]ResolverEntry
+}
+
+func createEntry(
+	line uint32,
+	ip net.IP,
+) ResolverEntry {
+	entry := ResolverEntry{
+		Line: line,
+	}
+
+	if ipv4 := ip.To4(); ipv4 != nil {
+		entry.IPv4Address = ipv4
+	} else if ipv6 := ip.To16(); ipv6 != nil {
+		entry.IPv6Address = ipv6
+	}
+
+	return entry
+}
+
+type hostnameEntry struct {
+	Location common.LocationRange
+	HostName string
+}
+
+func CreateResolverFromParser(p tree.HostsParser) (Resolver, []common.LSPError) {
+	errors := make([]common.LSPError, 0)
+	resolver := Resolver{
+		Entries: make(map[string]ResolverEntry),
+	}
+
+	for lineNumber, entry := range p.Tree.Entries {
+		if entry.IPAddress != nil && entry.Hostname != nil {
+			hostNames := append(
+				[]hostnameEntry{
+					{
+						Location: entry.Hostname.Location,
+						HostName: entry.Hostname.Value,
+					},
+				},
+				utils.Map(
+					entry.Aliases,
+					func(alias *tree.HostsHostname) hostnameEntry {
+						return hostnameEntry{
+							Location: alias.Location,
+							HostName: alias.Value,
+						}
+					},
+				)...,
+			)
+
+			for _, hostName := range hostNames {
+				entry := createEntry(
+					lineNumber,
+					entry.IPAddress.Value.IP,
+				)
+
+				if resolv, found := resolver.Entries[hostName.HostName]; found {
+					errors = append(
+						errors,
+						common.LSPError{
+							Range: hostName.Location,
+							Err: DuplicateHostEntry{
+								AlreadyFoundAt: resolv.Line,
+								Hostname:       hostName.HostName,
+							},
+						},
+					)
+				} else {
+					resolver.Entries[hostName.HostName] = entry
+				}
+			}
+		}
+	}
+
+	return resolver, errors
+}

handlers/hosts/handlers/analyzer_test.go

@@ -0,0 +1,117 @@
+package handlers
+
+import (
+	"config-lsp/handlers/hosts/tree"
+	"config-lsp/utils"
+	"testing"
+)
+
+func TestResolverEntriesWorksWithNonOverlapping(
+	t *testing.T,
+) {
+	input := utils.Dedent(`
+1.2.3.4 hello.com
+5.5.5.5 world.com
+`)
+
+	parser := tree.CreateNewHostsParser()
+	errors := parser.Parse(input)
+
+	if len(errors) != 0 {
+		t.Fatalf("PARER FAILED! Expected no errors, but got %v", errors)
+	}
+
+	resolver, errors := CreateResolverFromParser(parser)
+
+	if len(errors) != 0 {
+		t.Errorf("Expected no errors, but got %v", errors)
+	}
+
+	if len(resolver.Entries) != 2 {
+		t.Errorf("Expected 2 entries, but got %v", len(resolver.Entries))
+	}
+
+	if !(resolver.Entries["hello.com"].IPv4Address.String() == "1.2.3.4") {
+		t.Errorf("Expected hello.com to be 1.2.3.4, but got %v", resolver.Entries["hello.com"].IPv4Address)
+	}
+
+	if !(resolver.Entries["world.com"].IPv4Address.String() == "5.5.5.5") {
+		t.Errorf("Expected world.com to be 5.5.5.5, but got %v", resolver.Entries["world.com"].IPv4Address)
+	}
+
+	if !(resolver.Entries["hello.com"].IPv6Address == nil) {
+		t.Errorf("Expected hello.com to have no IPv6 address, but got %v", resolver.Entries["hello.com"].IPv6Address)
+	}
+
+	if !(resolver.Entries["world.com"].IPv6Address == nil) {
+		t.Errorf("Expected world.com to have no IPv6 address, but got %v", resolver.Entries["world.com"].IPv6Address)
+	}
+}
+
+func TestResolverEntriesWithSimpleOverlapping(
+	t *testing.T,
+) {
+	input := utils.Dedent(`
+1.2.3.4 hello.com
+5.5.5.5 hello.com
+`)
+
+	parser := tree.CreateNewHostsParser()
+	errors := parser.Parse(input)
+
+	if len(errors) != 0 {
+		t.Fatalf("PARER FAILED! Expected no errors, but got %v", errors)
+	}
+
+	resolver, errors := CreateResolverFromParser(parser)
+
+	if !(len(errors) == 1) {
+		t.Errorf("Expected 1 error, but got %v", len(errors))
+	}
+
+	if len(resolver.Entries) != 1 {
+		t.Errorf("Expected 1 entry, but got %v", len(resolver.Entries))
+	}
+
+	if !(resolver.Entries["hello.com"].IPv4Address.String() == "1.2.3.4") {
+		t.Errorf("Expected hello.com to be 1.2.3.4, but got %v", resolver.Entries["hello.com"].IPv4Address)
+	}
+}
+
+func TestResolverEntriesWithComplexOverlapping(
+	t *testing.T,
+) {
+	input := utils.Dedent(`
+1.2.3.4 hello.com test.com
+5.5.5.5 check.com test.com
+`)
+
+	parser := tree.CreateNewHostsParser()
+	errors := parser.Parse(input)
+
+	if len(errors) != 0 {
+		t.Fatalf("PARER FAILED! Expected no errors, but got %v", errors)
+	}
+
+	resolver, errors := CreateResolverFromParser(parser)
+
+	if !(len(errors) == 1) {
+		t.Errorf("Expected 1 error, but got %v", len(errors))
+	}
+
+	if len(resolver.Entries) != 3 {
+		t.Errorf("Expected 3 entries, but got %v", len(resolver.Entries))
+	}
+
+	if !(resolver.Entries["hello.com"].IPv4Address.String() == "1.2.3.4") {
+		t.Errorf("Expected hello.com to be 1.2.3.4, but got %v", resolver.Entries["hello.com"].IPv4Address)
+	}
+
+	if !(resolver.Entries["check.com"].IPv4Address.String() == "5.5.5.5") {
+		t.Errorf("Expected check.com to be 5.5.5.5, but got %v", resolver.Entries["check.com"].IPv4Address)
+	}
+
+	if !(resolver.Entries["test.com"].IPv4Address.String() == "1.2.3.4") {
+		t.Errorf("Expected test.com to have no IPv4 address, but got %v", resolver.Entries["test.com"].IPv4Address)
+	}
+}

handlers/hosts/handlers/errors.go

@@ -0,0 +1,12 @@
+package handlers
+
+import "fmt"
+
+type DuplicateHostEntry struct {
+	AlreadyFoundAt uint32
+	Hostname       string
+}
+
+func (d DuplicateHostEntry) Error() string {
+	return fmt.Sprintf("'%s' already defined on line %d", d.Hostname, d.AlreadyFoundAt)
+}

handlers/hosts/tree/handler_test.go

@@ -2,6 +2,7 @@ package tree
 
 import (
 	"config-lsp/utils"
+	"net"
 	"testing"
 )
 
@@ -27,7 +28,7 @@ func TestValidSimpleExampleWorks(
 		t.Errorf("Expected IP address to be present, but got nil")
 	}
 
-	if !(parser.Tree.Entries[1].IPAddress.Value == "1.2.3.4") {
+	if !(parser.Tree.Entries[1].IPAddress.Value.String() == net.ParseIP("1.2.3.4").String()) {
 		t.Errorf("Expected IP address to be 1.2.3.4, but got %v", parser.Tree.Entries[1].IPAddress.Value)
 	}
 
@@ -94,7 +95,7 @@ func TestValidComplexExampleWorks(
 		t.Errorf("Expected IP address to be present, but got nil")
 	}
 
-	if !(parser.Tree.Entries[3].IPAddress.Value == "1.2.3.4") {
+	if !(parser.Tree.Entries[3].IPAddress.Value.String() == net.ParseIP("1.2.3.4").String()) {
 		t.Errorf("Expected IP address to be 1.2.3.4, but got %v", parser.Tree.Entries[2].IPAddress.Value)
 	}
 
@@ -129,7 +130,7 @@ func TestInvalidExampleWorks(
 		t.Errorf("Expected no comment lines, but got %v", len(parser.CommentLines))
 	}
 
-	if !(parser.Tree.Entries[1].IPAddress.Value == "1.2.3.4") {
+	if !(parser.Tree.Entries[1].IPAddress.Value.String() == net.ParseIP("1.2.3.4").String()) {
 		t.Errorf("Expected IP address to be nil, but got %v", parser.Tree.Entries[1].IPAddress)
 	}
 

handlers/hosts/tree/hosts.go

@@ -3,6 +3,7 @@ package tree
 import (
 	"config-lsp/common"
 	"fmt"
+	"net"
 
 	"github.com/antlr4-go/antlr/v4"
 )
@@ -48,7 +49,7 @@ func (p HostsEntry) String() string {
 	str := fmt.Sprintf("HostsEntry(%v)", p.Location)
 
 	if p.IPAddress != nil {
-		str += " " + p.IPAddress.Value
+		str += " " + p.IPAddress.Value.String()
 	}
 
 	if p.Hostname != nil {
@@ -64,7 +65,7 @@ func (p HostsEntry) String() string {
 
 type HostsIPAddress struct {
 	Location common.LocationRange
-	Value    string
+	Value    net.IPAddr
 }
 
 type HostsHostname struct {

handlers/hosts/tree/listener.go

@@ -2,7 +2,9 @@ package tree
 
 import (
 	"config-lsp/common"
+	docvalues "config-lsp/doc-values"
 	"config-lsp/handlers/hosts/parser"
+	"net"
 
 	"github.com/antlr4-go/antlr/v4"
 )
@@ -14,6 +16,7 @@ type hostsListenerContext struct {
 type hostsParserListener struct {
 	*parser.BaseHostsListener
 	Parser       *HostsParser
+	Errors       []common.LSPError
 	hostsContext hostsListenerContext
 }
 
@@ -35,11 +38,30 @@ func (s *hostsParserListener) EnterIpAddress(ctx *parser.IpAddressContext) {
 	location := characterRangeFromCtx(ctx.BaseParserRuleContext)
 	location.ChangeBothLines(s.hostsContext.line)
 
+	ip := net.ParseIP(ctx.GetText())
+
+	if ip == nil {
+		s.Errors = append(s.Errors, common.LSPError{
+			Range: location,
+			Err:   docvalues.InvalidIPAddress{},
+		})
+		return
+	}
+
+	ipAddr, err := net.ResolveIPAddr("ip", ip.String())
+
+	if err != nil {
+		s.Errors = append(s.Errors, common.LSPError{
+			Range: location,
+			Err:   docvalues.InvalidIPAddress{},
+		})
+	}
+
 	entry := s.Parser.Tree.Entries[location.Start.Line]
 
 	entry.IPAddress = &HostsIPAddress{
 		Location: location,
-		Value:    ctx.GetText(),
+		Value:    *ipAddr,
 	}
 }
 
@@ -91,6 +113,7 @@ func createHostsFileListener(
 		hostsContext: hostsListenerContext{
 			line: line,
 		},
+		Errors: make([]common.LSPError, 0),
 	}
 }