internal/app/state: improve store internals

This fully exposes the store internals for #19 and are final preparations for removing the legacy store interface.

This change also fixes a potential deadlock in the handle initialisation mkdir failure path. This however is never reachable in hakurei as the store is never accessed concurrently.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 246 insertions, 6 deletions

diff --git a/internal/app/state/store_test.go b/internal/app/state/store_test.go
index 8aa348a8..f58be18f 100644
--- a/internal/app/state/store_test.go
+++ b/internal/app/state/store_test.go
@@ -1,14 +1,254 @@
-package state_test
+package state
 
 import (
-	"log"
+	"cmp"
+	"iter"
+	"os"
+	"reflect"
+	"slices"
+	"strconv"
+	"strings"
+	"syscall"
 	"testing"
 
 	"hakurei.app/container/check"
-	"hakurei.app/internal/app/state"
-	"hakurei.app/message"
+	"hakurei.app/hst"
 )
 
-func TestMulti(t *testing.T) {
-	testStore(t, state.NewMulti(message.NewMsg(log.New(log.Writer(), "multi: ", 0)), check.MustAbs(t.TempDir())))
+func TestStateStoreBigLock(t *testing.T) {
+	t.Parallel()
+
+	{
+		s := newStore(check.MustAbs(t.TempDir()).Append("state"))
+		for i := 0; i < 2; i++ { // check once behaviour
+			if unlock, err := s.bigLock(); err != nil {
+				t.Fatalf("bigLock: error = %v", err)
+			} else {
+				unlock()
+			}
+		}
+	}
+
+	t.Run("mkdir", func(t *testing.T) {
+		t.Parallel()
+
+		wantErr := &hst.AppError{Step: "create state store directory",
+			Err: &os.PathError{Op: "mkdir", Path: "/proc/nonexistent", Err: syscall.ENOENT}}
+		for i := 0; i < 2; i++ { // check once behaviour
+			if _, err := newStore(check.MustAbs("/proc/nonexistent")).bigLock(); !reflect.DeepEqual(err, wantErr) {
+				t.Errorf("bigLock: error = %#v, want %#v", err, wantErr)
+			}
+		}
+	})
+
+	t.Run("access", func(t *testing.T) {
+		t.Parallel()
+
+		base := check.MustAbs(t.TempDir()).Append("inaccessible")
+		if err := os.MkdirAll(base.String(), 0); err != nil {
+			t.Fatal(err.Error())
+		}
+
+		wantErr := &hst.AppError{Step: "acquire lock on the state store",
+			Err: &os.PathError{Op: "open", Path: base.Append(storeMutexName).String(), Err: syscall.EACCES}}
+		if _, err := newStore(base).bigLock(); !reflect.DeepEqual(err, wantErr) {
+			t.Errorf("bigLock: error = %#v, want %#v", err, wantErr)
+		}
+	})
+}
+
+func TestStateStoreIdentityHandle(t *testing.T) {
+	t.Parallel()
+
+	t.Run("loadstore", func(t *testing.T) {
+		t.Parallel()
+
+		s := newStore(check.MustAbs(t.TempDir()).Append("store"))
+
+		var handleAddr [8]*storeHandle
+		checkHandle := func(identity int, load bool) {
+			if h, err := s.identityHandle(identity); err != nil {
+				t.Fatalf("identityHandle: error = %v", err)
+			} else if load != (handleAddr[identity] != nil) {
+				t.Fatalf("identityHandle: load = %v, want %v", load, handleAddr[identity] != nil)
+			} else if !load {
+				handleAddr[identity] = h
+
+				if h.identity != identity {
+					t.Errorf("identityHandle: identity = %d, want %d", h.identity, identity)
+				}
+			} else if h != handleAddr[identity] {
+				t.Fatalf("identityHandle: %p, want %p", h, handleAddr[identity])
+			}
+		}
+
+		checkHandle(0, false)
+		checkHandle(1, false)
+		checkHandle(2, false)
+		checkHandle(3, false)
+		checkHandle(7, false)
+		checkHandle(7, true)
+		checkHandle(2, true)
+		checkHandle(1, true)
+		checkHandle(2, true)
+		checkHandle(0, true)
+	})
+
+	t.Run("access", func(t *testing.T) {
+		t.Parallel()
+
+		base := check.MustAbs(t.TempDir()).Append("inaccessible")
+		if err := os.MkdirAll(base.String(), 0); err != nil {
+			t.Fatal(err.Error())
+		}
+
+		wantErr := &hst.AppError{Step: "acquire lock on the state store",
+			Err: &os.PathError{Op: "open", Path: base.Append(storeMutexName).String(), Err: syscall.EACCES}}
+		if _, err := newStore(base).identityHandle(0); !reflect.DeepEqual(err, wantErr) {
+			t.Errorf("identityHandle: error = %#v, want %#v", err, wantErr)
+		}
+	})
+
+	t.Run("access segment", func(t *testing.T) {
+		t.Parallel()
+
+		base := check.MustAbs(t.TempDir()).Append("inaccessible")
+		if err := os.MkdirAll(base.String(), 0700); err != nil {
+			t.Fatal(err.Error())
+		}
+		if f, err := os.Create(base.Append(storeMutexName).String()); err != nil {
+			t.Fatal(err.Error())
+		} else if err = f.Close(); err != nil {
+			t.Fatal(err.Error())
+		}
+		if err := os.Chmod(base.String(), 0100); err != nil {
+			t.Fatal(err.Error())
+		}
+		t.Cleanup(func() {
+			if err := os.Chmod(base.String(), 0700); err != nil {
+				t.Fatal(err.Error())
+			}
+		})
+
+		wantErr := &hst.AppError{Step: "create store segment directory",
+			Err: &os.PathError{Op: "mkdir", Path: base.Append("0").String(), Err: syscall.EACCES}}
+		if _, err := newStore(base).identityHandle(0); !reflect.DeepEqual(err, wantErr) {
+			t.Errorf("identityHandle: error = %#v, want %#v", err, wantErr)
+		}
+	})
+}
+
+func TestStateStoreSegments(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		ents [2][]string
+		want []segmentIdentity
+		ext  func(t *testing.T, segments iter.Seq[segmentIdentity], n int)
+	}{
+		{"errors", [2][]string{{
+			"f0-invalid-file",
+		}, {
+			"f1-invalid-syntax",
+			"9999",
+			"16384",
+		}}, []segmentIdentity{
+			{-1, &hst.AppError{Step: "process store segment", Err: syscall.EISDIR,
+				Msg: `skipped non-directory entry "f0-invalid-file"`}},
+			{-1, &hst.AppError{Step: "process store segment", Err: syscall.ERANGE,
+				Msg: `skipped out of bounds entry 16384`}},
+			{-1, &hst.AppError{Step: "process store segment",
+				Err: &strconv.NumError{Func: "Atoi", Num: "f1-invalid-syntax", Err: strconv.ErrSyntax},
+				Msg: `skipped non-identity entry "f1-invalid-syntax"`}},
+			{9999, nil},
+		}, nil},
+
+		{"success", [2][]string{{
+			"lock",
+		}, {
+			"0",
+			"1",
+			"2",
+			"3",
+			"4",
+			"5",
+			"6",
+			"7",
+			"9",
+			"13",
+			"20",
+			"31",
+			"197",
+		}}, []segmentIdentity{
+			{0, nil},
+			{1, nil},
+			{2, nil},
+			{3, nil},
+			{4, nil},
+			{5, nil},
+			{6, nil},
+			{7, nil},
+			{9, nil},
+			{13, nil},
+			{20, nil},
+			{31, nil},
+			{197, nil},
+		}, func(t *testing.T, segments iter.Seq[segmentIdentity], n int) {
+			if n != 13 {
+				t.Fatalf("segments: n = %d", n)
+			}
+
+			// check partial drain
+			for range segments {
+				break
+			}
+		}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			base := check.MustAbs(t.TempDir()).Append("store")
+			if err := os.Mkdir(base.String(), 0700); err != nil {
+				t.Fatal(err.Error())
+			}
+			createEntries(t, base, tc.ents)
+
+			var got []segmentIdentity
+			if segments, n, err := newStore(base).segments(); err != nil {
+				t.Fatalf("segments: error = %v", err)
+			} else {
+				got = slices.AppendSeq(make([]segmentIdentity, 0, n), segments)
+				if tc.ext != nil {
+					tc.ext(t, segments, n)
+				}
+			}
+
+			slices.SortFunc(got, func(a, b segmentIdentity) int {
+				if a.identity == b.identity {
+					return strings.Compare(a.err.Error(), b.err.Error())
+				}
+				return cmp.Compare(a.identity, b.identity)
+			})
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("segments: %#v, want %#v", got, tc.want)
+			}
+		})
+	}
+
+	t.Run("access", func(t *testing.T) {
+		t.Parallel()
+
+		base := check.MustAbs(t.TempDir()).Append("inaccessible")
+		if err := os.MkdirAll(base.String(), 0); err != nil {
+			t.Fatal(err.Error())
+		}
+
+		wantErr := &hst.AppError{Step: "acquire lock on the state store",
+			Err: &os.PathError{Op: "open", Path: base.Append(storeMutexName).String(), Err: syscall.EACCES}}
+		if _, _, err := newStore(base).segments(); !reflect.DeepEqual(err, wantErr) {
+			t.Errorf("segments: error = %#v, want %#v", err, wantErr)
+		}
+	})
 }