test.go

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package sumdb
     6  
     7  import (
     8  	"context"
     9  	"fmt"
    10  	"sync"
    11  
    12  	"golang.org/x/mod/module"
    13  	"golang.org/x/mod/sumdb/note"
    14  	"golang.org/x/mod/sumdb/tlog"
    15  )
    16  
    17  // NewTestServer constructs a new [TestServer]
    18  // that will sign its tree with the given signer key
    19  // (see [golang.org/x/mod/sumdb/note])
    20  // and fetch new records as needed by calling gosum.
    21  func NewTestServer(signer string, gosum func(path, vers string) ([]byte, error)) *TestServer {
    22  	return &TestServer{signer: signer, gosum: gosum}
    23  }
    24  
    25  // A TestServer is an in-memory implementation of [ServerOps] for testing.
    26  type TestServer struct {
    27  	signer string
    28  	gosum  func(path, vers string) ([]byte, error)
    29  
    30  	mu      sync.Mutex
    31  	hashes  testHashes
    32  	records [][]byte
    33  	lookup  map[string]int64
    34  }
    35  
    36  // testHashes implements tlog.HashReader, reading from a slice.
    37  type testHashes []tlog.Hash
    38  
    39  func (h testHashes) ReadHashes(indexes []int64) ([]tlog.Hash, error) {
    40  	var list []tlog.Hash
    41  	for _, id := range indexes {
    42  		list = append(list, h[id])
    43  	}
    44  	return list, nil
    45  }
    46  
    47  func (s *TestServer) Signed(ctx context.Context) ([]byte, error) {
    48  	s.mu.Lock()
    49  	defer s.mu.Unlock()
    50  
    51  	size := int64(len(s.records))
    52  	h, err := tlog.TreeHash(size, s.hashes)
    53  	if err != nil {
    54  		return nil, err
    55  	}
    56  	text := tlog.FormatTree(tlog.Tree{N: size, Hash: h})
    57  	signer, err := note.NewSigner(s.signer)
    58  	if err != nil {
    59  		return nil, err
    60  	}
    61  	return note.Sign(&note.Note{Text: string(text)}, signer)
    62  }
    63  
    64  func (s *TestServer) ReadRecords(ctx context.Context, id, n int64) ([][]byte, error) {
    65  	s.mu.Lock()
    66  	defer s.mu.Unlock()
    67  
    68  	var list [][]byte
    69  	for i := int64(0); i < n; i++ {
    70  		if id+i >= int64(len(s.records)) {
    71  			return nil, fmt.Errorf("missing records")
    72  		}
    73  		list = append(list, s.records[id+i])
    74  	}
    75  	return list, nil
    76  }
    77  
    78  func (s *TestServer) Lookup(ctx context.Context, m module.Version) (int64, error) {
    79  	key := m.String()
    80  	s.mu.Lock()
    81  	id, ok := s.lookup[key]
    82  	s.mu.Unlock()
    83  	if ok {
    84  		return id, nil
    85  	}
    86  
    87  	// Look up module and compute go.sum lines.
    88  	data, err := s.gosum(m.Path, m.Version)
    89  	if err != nil {
    90  		return 0, err
    91  	}
    92  
    93  	s.mu.Lock()
    94  	defer s.mu.Unlock()
    95  
    96  	// We ran the fetch without the lock.
    97  	// If another fetch happened and committed, use it instead.
    98  	id, ok = s.lookup[key]
    99  	if ok {
   100  		return id, nil
   101  	}
   102  
   103  	// Add record.
   104  	id = int64(len(s.records))
   105  	s.records = append(s.records, data)
   106  	if s.lookup == nil {
   107  		s.lookup = make(map[string]int64)
   108  	}
   109  	s.lookup[key] = id
   110  	hashes, err := tlog.StoredHashesForRecordHash(id, tlog.RecordHash(data), s.hashes)
   111  	if err != nil {
   112  		panic(err)
   113  	}
   114  	s.hashes = append(s.hashes, hashes...)
   115  
   116  	return id, nil
   117  }
   118  
   119  func (s *TestServer) ReadTileData(ctx context.Context, t tlog.Tile) ([]byte, error) {
   120  	s.mu.Lock()
   121  	defer s.mu.Unlock()
   122  
   123  	return tlog.ReadTileData(t, s.hashes)
   124  }
   125
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