kythe.io@v0.0.68-0.20240422202219-7225dbc01741/kythe/cxx/extractor/bazel_artifact_reader.h (about)

     1  /*
     2   * Copyright 2020 The Kythe Authors. All rights reserved.
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *   http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  #ifndef KYTHE_CXX_EXTRACTOR_BAZEL_ARTIFACT_READER_H_
    17  #define KYTHE_CXX_EXTRACTOR_BAZEL_ARTIFACT_READER_H_
    18  
    19  #include <functional>
    20  #include <string>
    21  #include <vector>
    22  
    23  #include "absl/container/flat_hash_map.h"
    24  #include "absl/container/flat_hash_set.h"
    25  #include "absl/log/die_if_null.h"
    26  #include "absl/status/status.h"
    27  #include "absl/types/variant.h"
    28  #include "kythe/cxx/extractor/bazel_artifact.h"
    29  #include "kythe/cxx/extractor/bazel_artifact_selector.h"
    30  #include "kythe/cxx/extractor/bazel_event_reader.h"
    31  #include "third_party/bazel/src/main/java/com/google/devtools/build/lib/buildeventstream/proto/build_event_stream.pb.h"
    32  
    33  namespace kythe {
    34  
    35  /// \brief A cursor which selects and filters extraction artifacts from an
    36  /// underlying Bazel BuildEvent stream.
    37  class BazelArtifactReader {
    38   public:
    39    using value_type = BazelArtifact;
    40    using reference = value_type&;
    41    using const_reference = const value_type&;
    42  
    43    /// \brief Returns a list of default BazelArtifactSelectors consisting of a
    44    /// default-constructed ExtraActionSelector.
    45    static std::vector<AnyArtifactSelector> DefaultSelectors();
    46  
    47    /// \brief Constructs a new BazelArtifactSelector over the provided event
    48    /// stream.
    49    explicit BazelArtifactReader(
    50        BazelEventReaderInterface* event_reader,
    51        std::vector<AnyArtifactSelector> selectors = DefaultSelectors())
    52        : event_reader_(ABSL_DIE_IF_NULL(event_reader)),
    53          selectors_(std::move(selectors)) {
    54      Select();
    55    }
    56  
    57    /// \brief Advances the event stream until the next artifact is found.
    58    /// Invokes all selectors on sequential events from the stream until at least
    59    /// one selector signals success.
    60    void Next();
    61  
    62    /// \brief Returns true if the underlying stream is exahusted and there are
    63    /// no more artifacts to find.
    64    bool Done() const { return value_.index() != 0; }
    65  
    66    /// \brief Returns a reference to the most recently selected artifact.
    67    /// Requires: Done() == false.
    68    reference Ref() { return absl::get<value_type>(value_); }
    69    const_reference Ref() const { return absl::get<value_type>(value_); }
    70  
    71    /// \brief Returns the overall status of the stream.
    72    /// Requires: Done() == true.
    73    absl::Status status() const { return absl::get<absl::Status>(value_); }
    74  
    75   private:
    76    void Select();
    77  
    78    absl::variant<value_type, absl::Status> value_;
    79    BazelEventReaderInterface* event_reader_;
    80    std::vector<AnyArtifactSelector> selectors_;
    81  };
    82  
    83  }  // namespace kythe
    84  
    85  #endif  // KYTHE_CXX_EXTRACTOR_BAZEL_ARTIFACT_READER_H_