1  // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
 2  // Use of this source code is governed by a BSD-style license that can be
 3  // found in the LICENSE file. See the AUTHORS file for names of contributors.
 4  
 5  #ifndef STORAGE_LEVELDB_UTIL_TESTUTIL_H_
 6  #define STORAGE_LEVELDB_UTIL_TESTUTIL_H_
 7  
 8  #include "helpers/memenv/memenv.h"
 9  #include "leveldb/env.h"
10  #include "leveldb/slice.h"
11  #include "util/random.h"
12  
13  namespace leveldb {
14  namespace test {
15  
16  // Store in *dst a random string of length "len" and return a Slice that
17  // references the generated data.
18  Slice RandomString(Random* rnd, int len, std::string* dst);
19  
20  // Return a random key with the specified length that may contain interesting
21  // characters (e.g. \x00, \xff, etc.).
22  std::string RandomKey(Random* rnd, int len);
23  
24  // Store in *dst a string of length "len" that will compress to
25  // "N*compressed_fraction" bytes and return a Slice that references
26  // the generated data.
27  Slice CompressibleString(Random* rnd, double compressed_fraction, size_t len,
28                           std::string* dst);
29  
30  // A wrapper that allows injection of errors.
31  class ErrorEnv : public EnvWrapper {
32   public:
33    bool writable_file_error_;
34    int num_writable_file_errors_;
35  
36    ErrorEnv()
37        : EnvWrapper(NewMemEnv(Env::Default())),
38          writable_file_error_(false),
39          num_writable_file_errors_(0) {}
40    ~ErrorEnv() override { delete target(); }
41  
42    Status NewWritableFile(const std::string& fname,
43                           WritableFile** result) override {
44      if (writable_file_error_) {
45        ++num_writable_file_errors_;
46        *result = nullptr;
47        return Status::IOError(fname, "fake error");
48      }
49      return target()->NewWritableFile(fname, result);
50    }
51  
52    Status NewAppendableFile(const std::string& fname,
53                             WritableFile** result) override {
54      if (writable_file_error_) {
55        ++num_writable_file_errors_;
56        *result = nullptr;
57        return Status::IOError(fname, "fake error");
58      }
59      return target()->NewAppendableFile(fname, result);
60    }
61  };
62  
63  }  // namespace test
64  }  // namespace leveldb
65  
66  #endif  // STORAGE_LEVELDB_UTIL_TESTUTIL_H_