chore(all): memory and thread safe storage

- settings: get filter choices from storage for settings validation
- updater: update servers to the storage
- storage: minimal deep copying and data duplication
- storage: add merged servers mutex for thread safety
- connection: filter servers in storage
- formatter: format servers to Markdown in storage
- PIA: get server by name from storage directly
- Updater: get servers count from storage directly
- Updater: equality check done in storage, fix #882

internal/models/server_test.go

@@ -0,0 +1,120 @@
+package models
+
+import (
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Server_Equal(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		a     *Server
+		b     Server
+		equal bool
+	}{
+		"same IPs": {
+			a: &Server{
+				IPs: []net.IP{net.IPv4(1, 2, 3, 4)},
+			},
+			b: Server{
+				IPs: []net.IP{net.IPv4(1, 2, 3, 4)},
+			},
+			equal: true,
+		},
+		"same IP strings": {
+			a: &Server{
+				IPs: []net.IP{net.IPv4(1, 2, 3, 4)},
+			},
+			b: Server{
+				IPs: []net.IP{{1, 2, 3, 4}},
+			},
+			equal: true,
+		},
+		"different IPs": {
+			a: &Server{
+				IPs: []net.IP{{1, 2, 3, 4}, {2, 3, 4, 5}},
+			},
+			b: Server{
+				IPs: []net.IP{{1, 2, 3, 4}, {1, 2, 3, 4}},
+			},
+		},
+		"all fields equal": {
+			a: &Server{
+				VPN:         "vpn",
+				Country:     "country",
+				Region:      "region",
+				City:        "city",
+				ISP:         "isp",
+				Owned:       true,
+				Number:      1,
+				ServerName:  "server_name",
+				Hostname:    "hostname",
+				TCP:         true,
+				UDP:         true,
+				OvpnX509:    "x509",
+				RetroLoc:    "retroloc",
+				MultiHop:    true,
+				WgPubKey:    "wgpubkey",
+				Free:        true,
+				Stream:      true,
+				PortForward: true,
+				IPs:         []net.IP{net.IPv4(1, 2, 3, 4)},
+			},
+			b: Server{
+				VPN:         "vpn",
+				Country:     "country",
+				Region:      "region",
+				City:        "city",
+				ISP:         "isp",
+				Owned:       true,
+				Number:      1,
+				ServerName:  "server_name",
+				Hostname:    "hostname",
+				TCP:         true,
+				UDP:         true,
+				OvpnX509:    "x509",
+				RetroLoc:    "retroloc",
+				MultiHop:    true,
+				WgPubKey:    "wgpubkey",
+				Free:        true,
+				Stream:      true,
+				PortForward: true,
+				IPs:         []net.IP{net.IPv4(1, 2, 3, 4)},
+			},
+			equal: true,
+		},
+		"different field": {
+			a: &Server{
+				VPN: "vpn",
+			},
+			b: Server{
+				VPN: "other vpn",
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			ipsOfANotNil := testCase.a.IPs != nil
+			ipsOfBNotNil := testCase.b.IPs != nil
+
+			equal := testCase.a.Equal(testCase.b)
+
+			assert.Equal(t, testCase.equal, equal)
+
+			// Ensure IPs field is not modified
+			if ipsOfANotNil {
+				assert.NotNil(t, testCase.a)
+			}
+			if ipsOfBNotNil {
+				assert.NotNil(t, testCase.b)
+			}
+		})
+	}
+}