1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252

package gitrepo

import (
	"os"
	"path/filepath"
	"sync"
	"testing"
	"time"

	"gitweb/internal/store"
)

// dirCount returns the number of children under the cache root.
func dirCount(t *testing.T, root string) int {
	t.Helper()
	children, err := os.ReadDir(root)
	if err != nil {
		t.Fatal(err)
	}
	return len(children)
}

// twoRepos builds two distinct bare repos in one LocalStore and returns the
// store and their repo paths.
func twoRepos(t *testing.T) (st store.Store, pathA, pathB string) {
	t.Helper()
	root := t.TempDir()
	pathA = makeBareRepo(t, root, "u@d.com", "a.git")
	pathB = makeBareRepo(t, root, "u@d.com", "b.git")
	return store.NewLocalStore(root), pathA, pathB
}

// repoBytes returns the materialized size of repoPath (sum of manifest sizes).
func repoBytes(t *testing.T, st store.Store, repoPath string) int64 {
	t.Helper()
	c := newTestCache(t, st, CacheOptions{})
	_, release, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	defer release()
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.total
}

func TestCacheByteEviction(t *testing.T) {
	st, pathA, pathB := twoRepos(t)
	sizeA := repoBytes(t, st, pathA)

	// Budget fits one repo but not two: getting B must evict A.
	dir := t.TempDir()
	c := newTestCache(t, st, CacheOptions{Dir: dir, BudgetBytes: sizeA + sizeA/2})

	rA, releaseA, err := c.Get(pathA)
	if err != nil {
		t.Fatal(err)
	}
	releaseA()
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("after Get A: %d dirs, want 1", got)
	}

	_, releaseB, err := c.Get(pathB)
	if err != nil {
		t.Fatal(err)
	}
	releaseB()
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("after Get B evicted A: %d dirs, want 1", got)
	}

	// A re-materializes on demand as a fresh entry.
	rA2, releaseA2, err := c.Get(pathA)
	if err != nil {
		t.Fatal(err)
	}
	defer releaseA2()
	if rA2 == rA {
		t.Fatal("expected evicted repo to re-materialize (different pointer)")
	}
}

func TestCacheHoldAcrossEviction(t *testing.T) {
	st, pathA, pathB := twoRepos(t)
	sizeA := repoBytes(t, st, pathA)

	dir := t.TempDir()
	c := newTestCache(t, st, CacheOptions{Dir: dir, BudgetBytes: sizeA + sizeA/2})

	rA, releaseA, err := c.Get(pathA)
	if err != nil {
		t.Fatal(err)
	}
	// A is still held when B evicts it: its dir must survive.
	_, releaseB, err := c.Get(pathB)
	if err != nil {
		t.Fatal(err)
	}
	defer releaseB()
	if got := dirCount(t, dir); got != 2 {
		t.Fatalf("evicted-but-held entry deleted early: %d dirs, want 2", got)
	}
	// The held repo still reads from its (retired) backing dir.
	if _, err := rA.Head(); err != nil {
		t.Fatalf("held repo unreadable after eviction: %v", err)
	}
	releaseA()
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("after release: %d dirs, want 1", got)
	}
}

func TestCacheInvalidateDuringHold(t *testing.T) {
	root := t.TempDir()
	repoPath := makeBareRepo(t, root, "u@d.com", "demo.git")
	st := store.NewLocalStore(root)

	dir := t.TempDir()
	c := newTestCache(t, st, CacheOptions{Dir: dir})

	r1, release1, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	c.Invalidate(repoPath)
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("invalidated-but-held entry deleted early: %d dirs, want 1", got)
	}
	if _, err := r1.Head(); err != nil {
		t.Fatalf("held repo unreadable after Invalidate: %v", err)
	}

	// A new Get re-materializes into a fresh dir.
	r2, release2, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	defer release2()
	if r2 == r1 {
		t.Fatal("expected fresh repo after Invalidate")
	}
	if got := dirCount(t, dir); got != 2 {
		t.Fatalf("old + new dirs: %d, want 2", got)
	}

	release1()
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("old dir survives its last release: %d dirs, want 1", got)
	}
}

func TestCacheConcurrentGet(t *testing.T) {
	root := t.TempDir()
	repoPath := makeBareRepo(t, root, "u@d.com", "demo.git")
	st := store.NewLocalStore(root)

	dir := t.TempDir()
	c := newTestCache(t, st, CacheOptions{Dir: dir})

	const n = 8
	var wg sync.WaitGroup
	errs := make(chan error, n)
	for range n {
		wg.Add(1)
		go func() {
			defer wg.Done()
			repo, release, err := c.Get(repoPath)
			if err != nil {
				errs <- err
				return
			}
			defer release()
			if _, err := repo.Head(); err != nil {
				errs <- err
			}
		}()
	}
	wg.Wait()
	close(errs)
	for err := range errs {
		t.Fatal(err)
	}

	// Race losers cleaned up after themselves: one dir remains.
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("%d dirs after concurrent Gets, want 1", got)
	}
	// And it is a usable cache hit.
	_, release, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	release()
}

func TestCacheStaleReleaseDeletesOldDir(t *testing.T) {
	root := t.TempDir()
	repoPath := makeBareRepo(t, root, "u@d.com", "demo.git")
	st := store.NewLocalStore(root)

	dir := t.TempDir()
	c := newTestCache(t, st, CacheOptions{Dir: dir})

	_, release1, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	release1()

	// Bump the repo's mtime so LocalStore.Seq changes; the stale entry (now
	// unreferenced) is retired and deleted during the next Get.
	later := time.Now().Add(2 * time.Second)
	if err := os.Chtimes(filepath.Join(root, repoPath, "HEAD"), later, later); err != nil {
		t.Fatal(err)
	}
	_, release2, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	defer release2()
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("stale dir not deleted: %d dirs, want 1", got)
	}
}

func TestCacheSingleRepoOverBudget(t *testing.T) {
	root := t.TempDir()
	repoPath := makeBareRepo(t, root, "u@d.com", "demo.git")
	st := store.NewLocalStore(root)

	// Budget of 1 byte: the sole entry must still be kept and servable.
	dir := t.TempDir()
	c := newTestCache(t, st, CacheOptions{Dir: dir, BudgetBytes: 1})

	r1, release1, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	release1()
	if got := dirCount(t, dir); got != 1 {
		t.Fatalf("sole over-budget entry evicted: %d dirs, want 1", got)
	}
	r2, release2, err := c.Get(repoPath)
	if err != nil {
		t.Fatal(err)
	}
	defer release2()
	if r1 != r2 {
		t.Fatal("expected the over-budget entry to be reused")
	}
}