ARROW-7439: [C++][Dataset] Remove pointer aliases

cpp/examples/arrow/dataset-parquet-scan-example.cc

@@ -65,7 +65,7 @@ struct Configuration {
   std::shared_ptr<ds::Expression> filter = ("total_amount"_ > 1000.0f).Copy();
 } conf;
 
-std::shared_ptr<ds::Dataset> GetDatasetFromPath(fs::FileSystemPtr fs,
+std::shared_ptr<ds::Dataset> GetDatasetFromPath(std::shared_ptr<fs::FileSystem> fs,
                                                 std::shared_ptr<ds::FileFormat> format,
                                                 std::string path) {
   // Find all files under `path`

cpp/src/arrow/dataset/dataset.cc

@@ -29,21 +29,22 @@
 namespace arrow {
 namespace dataset {
 
-DataFragment::DataFragment(ScanOptionsPtr scan_options)
+DataFragment::DataFragment(std::shared_ptr<ScanOptions> scan_options)
     : scan_options_(std::move(scan_options)), partition_expression_(scalar(true)) {}
 
 SimpleDataFragment::SimpleDataFragment(
-    std::vector<std::shared_ptr<RecordBatch>> record_batches, ScanOptionsPtr scan_options)
+    std::vector<std::shared_ptr<RecordBatch>> record_batches,
+    std::shared_ptr<ScanOptions> scan_options)
     : DataFragment(std::move(scan_options)), record_batches_(std::move(record_batches)) {}
 
-Result<ScanTaskIterator> SimpleDataFragment::Scan(ScanContextPtr context) {
+Result<ScanTaskIterator> SimpleDataFragment::Scan(std::shared_ptr<ScanContext> context) {
   // Make an explicit copy of record_batches_ to ensure Scan can be called
   // multiple times.
   auto batches_it = MakeVectorIterator(record_batches_);
 
   // RecordBatch -> ScanTask
   auto scan_options = scan_options_;
-  auto fn = [=](std::shared_ptr<RecordBatch> batch) -> ScanTaskPtr {
+  auto fn = [=](std::shared_ptr<RecordBatch> batch) -> std::shared_ptr<ScanTask> {
     std::vector<std::shared_ptr<RecordBatch>> batches{batch};
     return ::arrow::internal::make_unique<SimpleScanTask>(
         std::move(batches), std::move(scan_options), std::move(context));
@@ -52,21 +53,23 @@ Result<ScanTaskIterator> SimpleDataFragment::Scan(ScanContextPtr context) {
   return MakeMapIterator(fn, std::move(batches_it));
 }
 
-Result<DatasetPtr> Dataset::Make(DataSourceVector sources,
-                                 std::shared_ptr<Schema> schema) {
-  return DatasetPtr(new Dataset(std::move(sources), std::move(schema)));
+Result<std::shared_ptr<Dataset>> Dataset::Make(DataSourceVector sources,
+                                               std::shared_ptr<Schema> schema) {
+  return std::shared_ptr<Dataset>(new Dataset(std::move(sources), std::move(schema)));
 }
 
-Result<ScannerBuilderPtr> Dataset::NewScan(ScanContextPtr context) {
+Result<std::shared_ptr<ScannerBuilder>> Dataset::NewScan(
+    std::shared_ptr<ScanContext> context) {
   return std::make_shared<ScannerBuilder>(this->shared_from_this(), context);
 }
 
-Result<ScannerBuilderPtr> Dataset::NewScan() {
+Result<std::shared_ptr<ScannerBuilder>> Dataset::NewScan() {
   return NewScan(std::make_shared<ScanContext>());
 }
 
 bool DataSource::AssumePartitionExpression(
-    const ScanOptionsPtr& scan_options, ScanOptionsPtr* simplified_scan_options) const {
+    const std::shared_ptr<ScanOptions>& scan_options,
+    std::shared_ptr<ScanOptions>* simplified_scan_options) const {
   if (partition_expression_ == nullptr) {
     if (simplified_scan_options != nullptr) {
       *simplified_scan_options = scan_options;
@@ -88,19 +91,21 @@ bool DataSource::AssumePartitionExpression(
   return true;
 }
 
-DataFragmentIterator DataSource::GetFragments(ScanOptionsPtr scan_options) {
-  ScanOptionsPtr simplified_scan_options;
+DataFragmentIterator DataSource::GetFragments(std::shared_ptr<ScanOptions> scan_options) {
+  std::shared_ptr<ScanOptions> simplified_scan_options;
   if (!AssumePartitionExpression(scan_options, &simplified_scan_options)) {
-    return MakeEmptyIterator<DataFragmentPtr>();
+    return MakeEmptyIterator<std::shared_ptr<DataFragment>>();
   }
   return GetFragmentsImpl(std::move(simplified_scan_options));
 }
 
-DataFragmentIterator SimpleDataSource::GetFragmentsImpl(ScanOptionsPtr scan_options) {
+DataFragmentIterator SimpleDataSource::GetFragmentsImpl(
+    std::shared_ptr<ScanOptions> scan_options) {
   return MakeVectorIterator(fragments_);
 }
 
-DataFragmentIterator TreeDataSource::GetFragmentsImpl(ScanOptionsPtr options) {
+DataFragmentIterator TreeDataSource::GetFragmentsImpl(
+    std::shared_ptr<ScanOptions> options) {
   return GetFragmentsFromSources(children_, options);
 }
 

cpp/src/arrow/dataset/dataset.h

@@ -38,7 +38,7 @@ class ARROW_DS_EXPORT DataFragment {
  public:
   /// \brief Scan returns an iterator of ScanTasks, each of which yields
   /// RecordBatches from this DataFragment.
-  virtual Result<ScanTaskIterator> Scan(ScanContextPtr context) = 0;
+  virtual Result<ScanTaskIterator> Scan(std::shared_ptr<ScanContext> context) = 0;
 
   /// \brief Return true if the fragment can benefit from parallel
   /// scanning
@@ -48,7 +48,7 @@ class ARROW_DS_EXPORT DataFragment {
   /// scanning this fragment. May be nullptr, which indicates that no filtering
   /// or schema reconciliation will be performed and all partitions will be
   /// scanned.
-  ScanOptionsPtr scan_options() const { return scan_options_; }
+  std::shared_ptr<ScanOptions> scan_options() const { return scan_options_; }
 
   virtual ~DataFragment() = default;
 
@@ -59,24 +59,25 @@ class ARROW_DS_EXPORT DataFragment {
   }
 
  protected:
-  explicit DataFragment(ScanOptionsPtr scan_options);
+  explicit DataFragment(std::shared_ptr<ScanOptions> scan_options);
 
-  DataFragment(ScanOptionsPtr scan_options, ExpressionPtr partition_expression)
+  DataFragment(std::shared_ptr<ScanOptions> scan_options,
+               std::shared_ptr<Expression> partition_expression)
       : scan_options_(std::move(scan_options)),
         partition_expression_(std::move(partition_expression)) {}
 
-  ScanOptionsPtr scan_options_;
-  ExpressionPtr partition_expression_;
+  std::shared_ptr<ScanOptions> scan_options_;
+  std::shared_ptr<Expression> partition_expression_;
 };
 
 /// \brief A trivial DataFragment that yields ScanTask out of a fixed set of
 /// RecordBatch.
 class ARROW_DS_EXPORT SimpleDataFragment : public DataFragment {
  public:
   SimpleDataFragment(std::vector<std::shared_ptr<RecordBatch>> record_batches,
-                     ScanOptionsPtr scan_options);
+                     std::shared_ptr<ScanOptions> scan_options);
 
-  Result<ScanTaskIterator> Scan(ScanContextPtr context) override;
+  Result<ScanTaskIterator> Scan(std::shared_ptr<ScanContext> context) override;
 
   bool splittable() const override { return false; }
 
@@ -91,11 +92,13 @@ class ARROW_DS_EXPORT DataSource {
  public:
   /// \brief GetFragments returns an iterator of DataFragments. The ScanOptions
   /// controls filtering and schema inference.
-  DataFragmentIterator GetFragments(ScanOptionsPtr options);
+  DataFragmentIterator GetFragments(std::shared_ptr<ScanOptions> options);
 
   /// \brief An expression which evaluates to true for all data viewed by this DataSource.
   /// May be null, which indicates no information is available.
-  const ExpressionPtr& partition_expression() const { return partition_expression_; }
+  const std::shared_ptr<Expression>& partition_expression() const {
+    return partition_expression_;
+  }
 
   /// \brief The name identifying the kind of data source
   virtual std::string type_name() const = 0;
@@ -104,16 +107,18 @@ class ARROW_DS_EXPORT DataSource {
 
  protected:
   DataSource() = default;
-  explicit DataSource(ExpressionPtr c) : partition_expression_(std::move(c)) {}
+  explicit DataSource(std::shared_ptr<Expression> c)
+      : partition_expression_(std::move(c)) {}
 
-  virtual DataFragmentIterator GetFragmentsImpl(ScanOptionsPtr options) = 0;
+  virtual DataFragmentIterator GetFragmentsImpl(std::shared_ptr<ScanOptions> options) = 0;
 
   /// Mutates a ScanOptions by assuming partition_expression_ holds for all yielded
   /// fragments. Returns false if the selector is not satisfiable in this DataSource.
-  virtual bool AssumePartitionExpression(const ScanOptionsPtr& scan_options,
-                                         ScanOptionsPtr* simplified_scan_options) const;
+  virtual bool AssumePartitionExpression(
+      const std::shared_ptr<ScanOptions>& scan_options,
+      std::shared_ptr<ScanOptions>* simplified_scan_options) const;
 
-  ExpressionPtr partition_expression_;
+  std::shared_ptr<Expression> partition_expression_;
 };
 
 /// \brief A DataSource consisting of a flat sequence of DataFragments
@@ -122,7 +127,7 @@ class ARROW_DS_EXPORT SimpleDataSource : public DataSource {
   explicit SimpleDataSource(DataFragmentVector fragments)
       : fragments_(std::move(fragments)) {}
 
-  DataFragmentIterator GetFragmentsImpl(ScanOptionsPtr options) override;
+  DataFragmentIterator GetFragmentsImpl(std::shared_ptr<ScanOptions> options) override;
 
   std::string type_name() const override { return "simple"; }
 
@@ -135,7 +140,7 @@ class ARROW_DS_EXPORT TreeDataSource : public DataSource {
  public:
   explicit TreeDataSource(DataSourceVector children) : children_(std::move(children)) {}
 
-  DataFragmentIterator GetFragmentsImpl(ScanOptionsPtr options) override;
+  DataFragmentIterator GetFragmentsImpl(std::shared_ptr<ScanOptions> options) override;
 
   std::string type_name() const override { return "tree"; }
 
@@ -151,12 +156,12 @@ class ARROW_DS_EXPORT Dataset : public std::enable_shared_from_this<Dataset> {
   //
   /// \param[in] sources one or more input data sources
   /// \param[in] schema a known schema to conform to
-  static Result<DatasetPtr> Make(DataSourceVector sources,
-                                 std::shared_ptr<Schema> schema);
+  static Result<std::shared_ptr<Dataset>> Make(DataSourceVector sources,
+                                               std::shared_ptr<Schema> schema);
 
   /// \brief Begin to build a new Scan operation against this Dataset
-  Result<ScannerBuilderPtr> NewScan(ScanContextPtr context);
-  Result<ScannerBuilderPtr> NewScan();
+  Result<std::shared_ptr<ScannerBuilder>> NewScan(std::shared_ptr<ScanContext> context);
+  Result<std::shared_ptr<ScannerBuilder>> NewScan();
 
   const DataSourceVector& sources() const { return sources_; }
 

cpp/src/arrow/dataset/dataset_internal.h

@@ -35,12 +35,12 @@ namespace dataset {
 /// \brief GetFragmentsFromSources transforms a vector<DataSource> into a
 /// flattened DataFragmentIterator.
 static inline DataFragmentIterator GetFragmentsFromSources(
-    const DataSourceVector& sources, ScanOptionsPtr options) {
+    const DataSourceVector& sources, std::shared_ptr<ScanOptions> options) {
   // Iterator<DataSource>
   auto sources_it = MakeVectorIterator(sources);
 
   // DataSource -> Iterator<DataFragment>
-  auto fn = [options](DataSourcePtr source) -> DataFragmentIterator {
+  auto fn = [options](std::shared_ptr<DataSource> source) -> DataFragmentIterator {
     return source->GetFragments(options);
   };
 

cpp/src/arrow/dataset/dataset_test.cc

@@ -298,7 +298,7 @@ TEST_F(TestEndToEnd, EndToEndSingleSource) {
   // A DataSource is composed of DataFragments. Each DataFragment can yield
   // multiple RecordBatches. DataSources can be created manually or "discovered"
   // via the DataSourceDiscovery interface.
-  DataSourceDiscoveryPtr discovery;
+  std::shared_ptr<DataSourceDiscovery> discovery;
 
   // The user must specify which FileFormat is used to create FileFragments.
   // This option is specific to FileSystemDataSource (and the builder).

cpp/src/arrow/dataset/discovery.cc

@@ -55,8 +55,8 @@ Result<std::shared_ptr<Schema>> DataSourceDiscovery::Inspect() {
 }
 
 FileSystemDataSourceDiscovery::FileSystemDataSourceDiscovery(
-    fs::FileSystemPtr filesystem, fs::PathForest forest, FileFormatPtr format,
-    FileSystemDiscoveryOptions options)
+    std::shared_ptr<fs::FileSystem> filesystem, fs::PathForest forest,
+    std::shared_ptr<FileFormat> format, FileSystemDiscoveryOptions options)
     : fs_(std::move(filesystem)),
       forest_(std::move(forest)),
       format_(std::move(format)),
@@ -78,8 +78,9 @@ bool StartsWithAnyOf(const std::vector<std::string>& prefixes, const std::string
 }
 
 Result<fs::PathForest> FileSystemDataSourceDiscovery::Filter(
-    const fs::FileSystemPtr& filesystem, const FileFormatPtr& format,
-    const FileSystemDiscoveryOptions& options, fs::PathForest forest) {
+    const std::shared_ptr<fs::FileSystem>& filesystem,
+    const std::shared_ptr<FileFormat>& format, const FileSystemDiscoveryOptions& options,
+    fs::PathForest forest) {
   fs::FileStatsVector out;
 
   auto& stats = forest.stats();
@@ -105,9 +106,9 @@ Result<fs::PathForest> FileSystemDataSourceDiscovery::Filter(
   return fs::PathForest::MakeFromPreSorted(std::move(out));
 }
 
-Result<DataSourceDiscoveryPtr> FileSystemDataSourceDiscovery::Make(
-    fs::FileSystemPtr filesystem, const std::vector<std::string>& paths,
-    FileFormatPtr format, FileSystemDiscoveryOptions options) {
+Result<std::shared_ptr<DataSourceDiscovery>> FileSystemDataSourceDiscovery::Make(
+    std::shared_ptr<fs::FileSystem> filesystem, const std::vector<std::string>& paths,
+    std::shared_ptr<FileFormat> format, FileSystemDiscoveryOptions options) {
   ARROW_ASSIGN_OR_RAISE(auto files, filesystem->GetTargetStats(paths));
   ARROW_ASSIGN_OR_RAISE(auto forest, fs::PathForest::Make(std::move(files)));
 
@@ -133,13 +134,13 @@ Result<DataSourceDiscoveryPtr> FileSystemDataSourceDiscovery::Make(
 
   ARROW_ASSIGN_OR_RAISE(forest, Filter(filesystem, format, options, std::move(forest)));
 
-  return DataSourceDiscoveryPtr(new FileSystemDataSourceDiscovery(
+  return std::shared_ptr<DataSourceDiscovery>(new FileSystemDataSourceDiscovery(
       filesystem, std::move(forest), std::move(format), std::move(options)));
 }
 
-Result<DataSourceDiscoveryPtr> FileSystemDataSourceDiscovery::Make(
-    fs::FileSystemPtr filesystem, fs::FileSelector selector, FileFormatPtr format,
-    FileSystemDiscoveryOptions options) {
+Result<std::shared_ptr<DataSourceDiscovery>> FileSystemDataSourceDiscovery::Make(
+    std::shared_ptr<fs::FileSystem> filesystem, fs::FileSelector selector,
+    std::shared_ptr<FileFormat> format, FileSystemDiscoveryOptions options) {
   ARROW_ASSIGN_OR_RAISE(auto files, filesystem->GetTargetStats(selector));
 
   ARROW_ASSIGN_OR_RAISE(auto forest, fs::PathForest::Make(std::move(files)));
@@ -153,7 +154,7 @@ Result<DataSourceDiscoveryPtr> FileSystemDataSourceDiscovery::Make(
     options.partition_base_dir = selector.base_dir;
   }
 
-  return DataSourceDiscoveryPtr(new FileSystemDataSourceDiscovery(
+  return std::shared_ptr<DataSourceDiscovery>(new FileSystemDataSourceDiscovery(
       filesystem, std::move(forest), std::move(format), std::move(options)));
 }
 
@@ -171,7 +172,7 @@ FileSystemDataSourceDiscovery::InspectSchemas() {
   return schemas;
 }
 
-Result<DataSourcePtr> FileSystemDataSourceDiscovery::Finish() {
+Result<std::shared_ptr<DataSource>> FileSystemDataSourceDiscovery::Finish() {
   ExpressionVector partitions(forest_.size(), scalar(true));
 
   // apply partition_scheme to forest to derive partitions