1 /* Copyright 2015 The TensorFlow Authors. All Rights Reserved. 2 3 Licensed under the Apache License, Version 2.0 (the "License"); 4 you may not use this file except in compliance with the License. 5 You may obtain a copy of the License at 6 7 http://www.apache.org/licenses/LICENSE-2.0 8 9 Unless required by applicable law or agreed to in writing, software 10 distributed under the License is distributed on an "AS IS" BASIS, 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 See the License for the specific language governing permissions and 13 limitations under the License. 14 ==============================================================================*/ 15 16 #include "tensorflow/core/framework/reader_base.h" 17 #include "tensorflow/core/framework/reader_op_kernel.h" 18 #include "tensorflow/core/lib/core/errors.h" 19 20 #include <sys/stat.h> 21 #include "lmdb.h" 22 23 namespace tensorflow { 24 25 #define MDB_CHECK(val) CHECK_EQ(val, MDB_SUCCESS) << mdb_strerror(val) 26 27 class LMDBReader : public ReaderBase { 28 public: 29 LMDBReader(const string& node_name, Env* /*unused*/) 30 : ReaderBase(strings::StrCat("LMDBReader '", node_name, "'")), 31 mdb_env_(nullptr), 32 mdb_dbi_(0), 33 mdb_txn_(nullptr), 34 mdb_cursor_(nullptr) {} 35 36 Status OnWorkStartedLocked() override { 37 MDB_CHECK(mdb_env_create(&mdb_env_)); 38 int flags = MDB_RDONLY | MDB_NOTLS | MDB_NOLOCK; 39 40 // Check if the LMDB filename is actually a file instead of a directory. 41 // If so, set appropriate flags so we can open it. 42 struct stat source_stat; 43 if (stat(current_work().c_str(), &source_stat) == 0 && 44 (source_stat.st_mode & S_IFREG)) { 45 flags |= MDB_NOSUBDIR; 46 } 47 48 MDB_CHECK(mdb_env_open(mdb_env_, current_work().c_str(), flags, 0664)); 49 MDB_CHECK(mdb_txn_begin(mdb_env_, nullptr, MDB_RDONLY, &mdb_txn_)); 50 MDB_CHECK(mdb_dbi_open(mdb_txn_, nullptr, 0, &mdb_dbi_)); 51 52 return Status::OK(); 53 } 54 55 Status OnWorkFinishedLocked() override { 56 if (mdb_env_ != nullptr) { 57 if (mdb_cursor_) { 58 mdb_cursor_close(mdb_cursor_); 59 mdb_cursor_ = nullptr; 60 } 61 mdb_dbi_close(mdb_env_, mdb_dbi_); 62 mdb_txn_abort(mdb_txn_); 63 mdb_env_close(mdb_env_); 64 mdb_txn_ = nullptr; 65 mdb_dbi_ = 0; 66 mdb_env_ = nullptr; 67 } 68 return Status::OK(); 69 } 70 71 Status ReadLocked(string* key, string* value, bool* produced, 72 bool* at_end) override { 73 if (mdb_cursor_ == nullptr) { 74 MDB_CHECK(mdb_cursor_open(mdb_txn_, mdb_dbi_, &mdb_cursor_)); 75 if (Seek(MDB_FIRST) == false) { 76 *at_end = true; 77 return Status::OK(); 78 } 79 } else { 80 if (Seek(MDB_NEXT) == false) { 81 *at_end = true; 82 return Status::OK(); 83 } 84 } 85 *key = string(static_cast<const char*>(mdb_key_.mv_data), mdb_key_.mv_size); 86 *value = string(static_cast<const char*>(mdb_value_.mv_data), 87 mdb_value_.mv_size); 88 *produced = true; 89 return Status::OK(); 90 } 91 92 Status ResetLocked() override { 93 CHECK_EQ(Seek(MDB_FIRST), true); 94 return ReaderBase::ResetLocked(); 95 } 96 97 private: 98 bool Seek(MDB_cursor_op op) { 99 CHECK_NOTNULL(mdb_cursor_); 100 int mdb_status = mdb_cursor_get(mdb_cursor_, &mdb_key_, &mdb_value_, op); 101 if (mdb_status == MDB_NOTFOUND) { 102 return false; 103 } else { 104 MDB_CHECK(mdb_status); 105 return true; 106 } 107 } 108 109 MDB_env* mdb_env_; 110 MDB_dbi mdb_dbi_; 111 112 MDB_txn* mdb_txn_; 113 MDB_cursor* mdb_cursor_; 114 MDB_val mdb_key_, mdb_value_; 115 }; 116 117 class LMDBReaderOp : public ReaderOpKernel { 118 public: 119 explicit LMDBReaderOp(OpKernelConstruction* context) 120 : ReaderOpKernel(context) { 121 Env* env = context->env(); 122 SetReaderFactory([this, env]() { return new LMDBReader(name(), env); }); 123 } 124 }; 125 126 REGISTER_KERNEL_BUILDER(Name("LMDBReader").Device(DEVICE_CPU), LMDBReaderOp); 127 128 } // namespace tensorflow 129
