ARROW-2229: [C++][Python] Add WriteCsv functionality.

cpp/src/arrow/CMakeLists.txt

@@ -349,6 +349,9 @@ if(ARROW_CSV)
               csv/options.cc
               csv/parser.cc
               csv/reader.cc)
+  if(ARROW_COMPUTE)
+    list(APPEND ARROW_SRCS csv/writer.cc)
+  endif()
 
   list(APPEND ARROW_TESTING_SRCS csv/test_common.cc)
 endif()

cpp/src/arrow/csv/CMakeLists.txt

@@ -15,14 +15,20 @@
 # specific language governing permissions and limitations
 # under the License.
 
-add_arrow_test(csv-test
-               SOURCES
-               chunker_test.cc
-               column_builder_test.cc
-               column_decoder_test.cc
-               converter_test.cc
-               parser_test.cc
-               reader_test.cc)
+set(CSV_TEST_SRCS
+    chunker_test.cc
+    column_builder_test.cc
+    column_decoder_test.cc
+    converter_test.cc
+    parser_test.cc
+    reader_test.cc)
+
+# Writer depends on compute's cast functionality
+if(ARROW_COMPUTE)
+  list(APPEND CSV_TEST_SRCS writer_test.cc)
+endif()
+
+add_arrow_test(csv-test SOURCES ${CSV_TEST_SRCS})
 
 add_arrow_benchmark(converter_benchmark PREFIX "arrow-csv")
 add_arrow_benchmark(parser_benchmark PREFIX "arrow-csv")

cpp/src/arrow/csv/api.h

@@ -19,3 +19,8 @@
 
 #include "arrow/csv/options.h"
 #include "arrow/csv/reader.h"
+
+// The writer depends on compute module for casting.
+#ifdef ARROW_COMPUTE
+#include "arrow/csv/writer.h"
+#endif

cpp/src/arrow/csv/options.cc

@@ -34,6 +34,7 @@ ConvertOptions ConvertOptions::Defaults() {
 }
 
 ReadOptions ReadOptions::Defaults() { return ReadOptions(); }
+WriteOptions WriteOptions::Defaults() { return WriteOptions(); }
 
 }  // namespace csv
 }  // namespace arrow

cpp/src/arrow/csv/options.h

@@ -137,5 +137,20 @@ struct ARROW_EXPORT ReadOptions {
   static ReadOptions Defaults();
 };
 
+/// Experimental
+struct ARROW_EXPORT WriteOptions {
+  /// Whether to write an initial header line with column names
+  bool include_header = true;
+
+  /// \brief Maximum number of rows processed at a time
+  ///
+  /// The CSV writer converts and writes data in batches of N rows.
+  /// This number can impact performance.
+  int32_t batch_size = 1024;
+
+  /// Create write options with default values
+  static WriteOptions Defaults();
+};
+
 }  // namespace csv
 }  // namespace arrow