feat(hosts): Add double ip analyzer

handlers/hosts/handlers/analyzer/analyzer.go

@@ -0,0 +1 @@
+package analyzer

handlers/hosts/handlers/analyzer/double_ips.go

@@ -0,0 +1,36 @@
+package analyzer
+
+import (
+	"config-lsp/common"
+	"config-lsp/handlers/hosts/tree"
+	"net"
+)
+
+func ipToString(ip net.IPAddr) string {
+	return ip.IP.String()
+}
+
+func analyzeDoubleIPs(p tree.HostsParser) []common.LSPError {
+	errors := make([]common.LSPError, 0)
+
+	ips := make(map[string]uint32)
+
+	for lineNumber, entry := range p.Tree.Entries {
+		if entry.IPAddress != nil {
+			key := ipToString(entry.IPAddress.Value)
+
+			if foundLine, found := ips[key]; found {
+				errors = append(errors, common.LSPError{
+					Range: entry.IPAddress.Location,
+					Err: DuplicateIPDeclaration{
+						AlreadyFoundAt: foundLine,
+					},
+				})
+			} else {
+				ips[key] = lineNumber
+			}
+		}
+	}
+
+	return errors
+}

handlers/hosts/handlers/analyzer/double_ips_test.go

@@ -0,0 +1,62 @@
+package analyzer
+
+import (
+	"config-lsp/handlers/hosts/tree"
+	"config-lsp/utils"
+	"testing"
+)
+
+func TestWorksWithNonDoubleIPs(
+	t *testing.T,
+) {
+	input := utils.Dedent(`
+1.2.3.4 hello.com
+5.5.5.5 world.com
+1.2.3.5 foo.com
+1.2.3.6 bar.com
+`)
+
+	parser := tree.CreateNewHostsParser()
+	errors := parser.Parse(input)
+
+	if len(errors) != 0 {
+		t.Fatalf("PARER FAILED! Expected no errors, but got %v", errors)
+	}
+
+	errors = analyzeDoubleIPs(parser)
+
+	if len(errors) != 0 {
+		t.Errorf("Expected no errors, but got %v", errors)
+	}
+}
+
+func TestWorksWithDoubleIPs(
+	t *testing.T,
+) {
+	input := utils.Dedent(`
+1.2.3.4 hello.com
+5.5.5.5 world.com
+1.2.3.4 foo.com
+`)
+
+	parser := tree.CreateNewHostsParser()
+	errors := parser.Parse(input)
+
+	if len(errors) != 0 {
+		t.Fatalf("PARER FAILED! Expected no errors, but got %v", errors)
+	}
+
+	errors = analyzeDoubleIPs(parser)
+
+	if !(len(errors) == 1) {
+		t.Errorf("Expected 1 error, but got %v", len(errors))
+	}
+
+	if !(errors[0].Range.Start.Line == 3) {
+		t.Errorf("Expected error on line 3, but got %v", errors[0].Range.Start.Line)
+	}
+
+	if !(errors[0].Err.(DuplicateIPDeclaration).AlreadyFoundAt == 1) {
+		t.Errorf("Expected error on line 1, but got %v", errors[0].Err.(DuplicateIPDeclaration).AlreadyFoundAt)
+	}
+}

handlers/hosts/handlers/analyzer/errors.go

@@ -1,4 +1,4 @@
-package handlers
+package analyzer
 
 import "fmt"
 
@@ -10,3 +10,11 @@ type DuplicateHostEntry struct {
 func (d DuplicateHostEntry) Error() string {
 	return fmt.Sprintf("'%s' already defined on line %d", d.Hostname, d.AlreadyFoundAt)
 }
+
+type DuplicateIPDeclaration struct {
+	AlreadyFoundAt uint32
+}
+
+func (d DuplicateIPDeclaration) Error() string {
+	return fmt.Sprintf("This IP address is already defined on line %d", d.AlreadyFoundAt)
+}

handlers/hosts/handlers/analyzer/resolver.go

@@ -1,4 +1,4 @@
-package handlers
+package analyzer
 
 import (
 	"config-lsp/common"

handlers/hosts/handlers/analyzer/resolver_test.go

@@ -1,4 +1,4 @@
-package handlers
+package analyzer
 
 import (
 	"config-lsp/handlers/hosts/tree"