generic: add MutexMap

ops/devcontainer/Dockerfile

@@ -1,13 +1,13 @@
 # A dev container.
 
-FROM alpine:3.22
+FROM alpine:3.24
 
 RUN apk add build-base git go sqlite vim shellcheck curl jq sudo bash docker
 
 # Busybox `less` doesn't appear to support colors (makes git diff lose color)
 RUN apk add less
 
-RUN curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b /usr/local/bin v2.0.2
+RUN curl -sSfL https://golangci-lint.run/install.sh | sh -s -- -b /usr/local/bin v2.14.0
 RUN GOBIN=/usr/local/bin go install git.offline-twitter.com/offline-labs/gocheckout@v0.0.2
 
 COPY etc/group /etc/group

pkg/codegen/modelgenerate/generate_model.go

@@ -296,9 +296,8 @@ func GenerateSaveItemFunc(tbl schema.Table) *ast.FuncDecl {
 	updatePairs := make([]string, 0, len(tbl.Columns))
 
 	hasCreatedAt, hasUpdatedAt := tbl.HasAutoTimestamps()
-	hasSoftDelete := tbl.HasSoftDelete()
 
-	// Assemble data for building SQL "insert" and "update" strings
+	// Assemble SQL "insert" string
 	for _, col := range tbl.Columns {
 		if col.Name == "rowid" {
 			continue
@@ -309,23 +308,20 @@ func GenerateSaveItemFunc(tbl schema.Table) *ast.FuncDecl {
 			val = fmt.Sprintf("nullif(%s, 0)", val)
 		}
 		insertVals = append(insertVals, val)
-		// created_at should not be updated after creation
-		if col.Name == "created_at" && hasCreatedAt {
-			continue
-		}
-		// Soft-delete state is managed by SoftDeleteXyz(), not by updates
-		if hasSoftDelete && (col.Name == "is_deleted" || col.Name == "deleted_at") {
-			continue
-		}
-		if !col.IsPrimaryKey { // Don't try to update primary key columns (mainly for w/o rowid tables)
-			updatePairs = append(updatePairs, col.Name+"="+val)
-		}
 	}
 	insertStmt := fmt.Sprintf("\n\t\t    insert into %s (%s)\n\t\t         values (%s)\n\t\t",
 		tbl.TableName,
 		strings.Join(insertCols, ", "),
 		strings.Join(insertVals, ", "),
 	)
+	// ...and "update" string
+	for _, col := range tbl.GetUpdateableColumns() {
+		val := ":" + col.Name
+		if col.IsNullableForeignKey() {
+			val = fmt.Sprintf("nullif(%s, 0)", val)
+		}
+		updatePairs = append(updatePairs, col.Name+"="+val)
+	}
 	updateStmt := fmt.Sprintf("\n\t\t    update %s\n\t\t       set %s\n\t\t     where rowid = :rowid\n\t\t",
 		tbl.TableName,
 		strings.Join(updatePairs, ",\n\t\t           "),

pkg/codegen/modelgenerate/generate_testfile.go

@@ -67,26 +67,18 @@ func SampleValue(c pkgschema.Column, offset int) ast.Expr {
 }
 
 // UpdateTestFields returns the columns for which the test generator should assign its own
-// sample values, in the MakeXyz() factory and in the create/update test: the same columns
+// sample values in MakeXyz() and the create/update test. It starts with Table.GetUpdateableColumns()
-// that GenerateSaveItemFunc's "update" branch writes to, minus foreign keys (which can't be
+// and removes fields the generated test should not assign directly: foreign keys and auto-managed
-// given plausible values here), the auto-managed "created_at"/"updated_at" columns, and the
+// updated_at.
-// soft-delete columns (which SoftDeleteXyz() manages).
 func UpdateTestFields(tbl pkgschema.Table) (ret []pkgschema.Column) {
-	hasCreatedAt, hasUpdatedAt := tbl.HasAutoTimestamps()
+	_, hasUpdatedAt := tbl.HasAutoTimestamps()
-	hasSoftDelete := tbl.HasSoftDelete()
+	for _, c := range tbl.GetUpdateableColumns() {
-	for _, c := range tbl.Columns {
+		if c.IsForeignKey {
-		if c.Name == "rowid" || c.IsPrimaryKey || c.IsForeignKey {
-			continue
-		}
-		if c.Name == "created_at" && hasCreatedAt {
 			continue
 		}
 		if c.Name == "updated_at" && hasUpdatedAt {
 			continue
 		}
-		if hasSoftDelete && (c.Name == "is_deleted" || c.Name == "deleted_at") {
-			continue
-		}
 		ret = append(ret, c)
 	}
 	return
@@ -486,6 +478,7 @@ func GenerateModelTestAST(tbl pkgschema.Table, schema pkgschema.Schema, gomodNam
 					makeDeepEqual(testObj, testObj2),
 				)
 
+				if len(tbl.GetUpdateableColumns()) > 0 { // Skip if no mutable fields
 					stmts = append(stmts,
 						BlankLine(),
 						Comment("Update"),
@@ -518,6 +511,7 @@ func GenerateModelTestAST(tbl pkgschema.Table, schema pkgschema.Schema, gomodNam
 						// if deep.Equal(...) {...}
 						makeDeepEqual(testObj, testObj2),
 					)
+				}
 
 				indexGets, hasIndexedGets := []ast.Stmt{
 					BlankLine(),

pkg/db/vsc.go

@@ -0,0 +1,51 @@
+package db
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"strings"
+)
+
+const separator = "\x1f"
+
+type VSC []string
+
+// MarshalJSON replaces `nil` with `[]` for hygiene.
+func (vs VSC) MarshalJSON() ([]byte, error) {
+	if vs == nil {
+		vs = VSC{}
+	}
+	return json.Marshal([]string(vs)) //nolint: wrapcheck // Passthrough
+}
+
+func (vs VSC) Value() (driver.Value, error) {
+	fields := make([]string, len(vs))
+	for i, v := range vs {
+		fields[i] = strings.ReplaceAll(v, separator, "")
+	}
+	return strings.Join(fields, separator), nil
+}
+
+var ErrWrongVSCType = errors.New("incompatible DB type for VSC")
+
+func (vs *VSC) Scan(src any) error {
+	var s string
+	switch v := src.(type) {
+	case string:
+		s = v
+	case []byte:
+		s = string(v)
+	case nil:
+		*vs = nil
+		return nil
+	default:
+		return ErrWrongVSCType
+	}
+	if s == "" {
+		*vs = VSC{}
+		return nil
+	}
+	*vs = strings.Split(s, separator)
+	return nil
+}

pkg/db/vsc_test.go

@@ -0,0 +1,48 @@
+package db_test
+
+import (
+	"testing"
+
+	"github.com/jmoiron/sqlx"
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/stretchr/testify/require"
+
+	"git.offline-twitter.com/offline-labs/gas-stack/pkg/db"
+)
+
+func TestVSCDBRoundTrip(t *testing.T) {
+	conn, err := sqlx.Open("sqlite3", ":memory:")
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, conn.Close()) })
+
+	_, err = conn.Exec(`create table vsc_items (id integer primary key, items text not null)`)
+	require.NoError(t, err)
+
+	type vscRow struct {
+		ID    int    `db:"id"`
+		Items db.VSC `db:"items"`
+	}
+
+	for _, want := range []vscRow{
+		{ID: 1, Items: db.VSC{"email"}},
+		{ID: 2, Items: db.VSC{"email", "profile"}},
+		{ID: 3, Items: db.VSC{}},
+	} {
+		_, err = conn.NamedExec(`insert into vsc_items (id, items) values (:id, :items)`, want)
+		require.NoError(t, err)
+
+		var got vscRow
+		require.NoError(t, conn.Get(&got, `select id, items from vsc_items where id = ?`, want.ID))
+		require.Equal(t, want, got)
+	}
+	t.Run("nil gets upgrade to empty list", func(t *testing.T) {
+		want := vscRow{ID: 4, Items: nil}
+		_, err = conn.NamedExec(`insert into vsc_items (id, items) values (:id, :items)`, want)
+		require.NoError(t, err)
+
+		var got vscRow
+		require.NoError(t, conn.Get(&got, `select id, items from vsc_items where id = ?`, want.ID))
+		require.NotNil(t, got.Items)
+		require.Equal(t, db.VSC{}, got.Items)
+	})
+}

pkg/generic/mutexmap.go

@@ -0,0 +1,76 @@
+package generic
+
+import (
+	"maps"
+	"sync"
+)
+
+type MutexMap[K comparable, V any] struct {
+	mu       sync.RWMutex
+	contents map[K]V
+}
+
+func NewMutexMap[K comparable, V any]() *MutexMap[K, V] {
+	return &MutexMap[K, V]{contents: make(map[K]V)}
+}
+
+func (m *MutexMap[K, V]) Set(key K, value V) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.contents[key] = value
+}
+
+func (m *MutexMap[K, V]) Get(key K) (V, bool) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	v, ok := m.contents[key]
+	return v, ok
+}
+
+func (m *MutexMap[K, V]) Len() int {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	return len(m.contents)
+}
+
+// Upd atomically updates the value for key.  `fn` is used to determine how to update an existing
+// value, if there is one.  It will be passed the existing value, and should return `(newValue V, shouldReplace bool)`.
+//
+// Returns the value that ends up associated with key after the call and whether an update occurred.
+func (m *MutexMap[K, V]) Upd(key K, fn func(prev V) (next V, shouldReplace bool)) (V, bool) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	prev := m.contents[key]
+	if next, shouldReplace := fn(prev); shouldReplace {
+		m.contents[key] = next
+		return next, true
+	}
+	return prev, false
+}
+
+// Del removes key from the map. Returns true if the key was present.
+func (m *MutexMap[K, V]) Del(key K) bool { //nolint: boolnames // Return value is incidental, not the main purpose of the function
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if _, ok := m.contents[key]; !ok {
+		return false
+	}
+	delete(m.contents, key)
+	return true
+}
+
+func (m *MutexMap[K, V]) Cpy() map[K]V {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	cp := make(map[K]V, len(m.contents))
+	maps.Copy(cp, m.contents)
+	return cp
+}
+
+func (m *MutexMap[K, V]) Pop(key K) (ret V, isOk bool) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	ret, isOk = m.contents[key]
+	delete(m.contents, key)
+	return
+}

pkg/schema/table.go

@@ -76,3 +76,21 @@ func (t Table) HasSoftDelete() bool {
 	}
 	return hasIsDeleted && hasDeletedAt
 }
+
+// GetUpdateableColumns returns the columns that should be written to by an "update" operation.
+func (t Table) GetUpdateableColumns() (ret []Column) {
+	hasCreatedAt, _ := t.HasAutoTimestamps()
+	for _, col := range t.Columns {
+		if col.Name == "rowid" || col.IsPrimaryKey {
+			continue // Rowid / primary key is never updateable
+		}
+		if col.Name == "created_at" && hasCreatedAt {
+			continue // Update shouldn't write `created_at`
+		}
+		if t.HasSoftDelete() && (col.Name == "is_deleted" || col.Name == "deleted_at") {
+			continue // Soft-delete state is managed by SoftDeleteXyz(), not by updates
+		}
+		ret = append(ret, col)
+	}
+	return
+}

pkg/schema/table_test.go

@@ -0,0 +1,34 @@
+package schema
+
+import "testing"
+
+func TestTableGetUpdateableColumns(t *testing.T) {
+	tbl := Table{
+		Columns: []Column{
+			{Name: "rowid"},
+			{Name: "version", Type: "integer", IsPrimaryKey: true},
+			{Name: "created_at", Type: "integer"},
+			{Name: "updated_at", Type: "integer"},
+			{Name: "is_deleted", Type: "integer"},
+			{Name: "deleted_at", Type: "integer"},
+			{Name: "owner_id", Type: "integer", IsForeignKey: true},
+			{Name: "name", Type: "text"},
+		},
+	}
+
+	gotColumns := tbl.GetUpdateableColumns()
+	got := make([]string, 0, len(gotColumns))
+	for _, col := range gotColumns {
+		got = append(got, col.Name)
+	}
+
+	want := []string{"updated_at", "owner_id", "name"}
+	if len(got) != len(want) {
+		t.Fatalf("GetUpdateableColumns() = %v, want %v", got, want)
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("GetUpdateableColumns() = %v, want %v", got, want)
+		}
+	}
+}