1 files changed, 126 insertions, 0 deletions
diff --git a/src/arrow/r/R/dplyr-join.R b/src/arrow/r/R/dplyr-join.R
new file mode 100644
index 000000000..c14b1a8f3
--- /dev/null
+++ b/src/arrow/r/R/dplyr-join.R
@@ -0,0 +1,126 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+
+# The following S3 methods are registered on load if dplyr is present
+
+do_join <- function(x,
+                    y,
+                    by = NULL,
+                    copy = FALSE,
+                    suffix = c(".x", ".y"),
+                    ...,
+                    keep = FALSE,
+                    na_matches,
+                    join_type) {
+  # TODO: handle `copy` arg: ignore?
+  # TODO: handle `suffix` arg: Arrow does prefix
+  # TODO: handle `keep` arg: "Should the join keys from both ‘x’ and ‘y’ be preserved in the output?"
+  # TODO: handle `na_matches` arg
+  x <- as_adq(x)
+  y <- as_adq(y)
+  by <- handle_join_by(by, x, y)
+
+  x$join <- list(
+    type = JoinType[[join_type]],
+    right_data = y,
+    by = by
+  )
+  collapse.arrow_dplyr_query(x)
+}
+
+left_join.arrow_dplyr_query <- function(x,
+                                        y,
+                                        by = NULL,
+                                        copy = FALSE,
+                                        suffix = c(".x", ".y"),
+                                        ...,
+                                        keep = FALSE) {
+  do_join(x, y, by, copy, suffix, ..., keep = keep, join_type = "LEFT_OUTER")
+}
+left_join.Dataset <- left_join.ArrowTabular <- left_join.arrow_dplyr_query
+
+right_join.arrow_dplyr_query <- function(x,
+                                         y,
+                                         by = NULL,
+                                         copy = FALSE,
+                                         suffix = c(".x", ".y"),
+                                         ...,
+                                         keep = FALSE) {
+  do_join(x, y, by, copy, suffix, ..., keep = keep, join_type = "RIGHT_OUTER")
+}
+right_join.Dataset <- right_join.ArrowTabular <- right_join.arrow_dplyr_query
+
+inner_join.arrow_dplyr_query <- function(x,
+                                         y,
+                                         by = NULL,
+                                         copy = FALSE,
+                                         suffix = c(".x", ".y"),
+                                         ...,
+                                         keep = FALSE) {
+  do_join(x, y, by, copy, suffix, ..., keep = keep, join_type = "INNER")
+}
+inner_join.Dataset <- inner_join.ArrowTabular <- inner_join.arrow_dplyr_query
+
+full_join.arrow_dplyr_query <- function(x,
+                                        y,
+                                        by = NULL,
+                                        copy = FALSE,
+                                        suffix = c(".x", ".y"),
+                                        ...,
+                                        keep = FALSE) {
+  do_join(x, y, by, copy, suffix, ..., keep = keep, join_type = "FULL_OUTER")
+}
+full_join.Dataset <- full_join.ArrowTabular <- full_join.arrow_dplyr_query
+
+semi_join.arrow_dplyr_query <- function(x,
+                                        y,
+                                        by = NULL,
+                                        copy = FALSE,
+                                        suffix = c(".x", ".y"),
+                                        ...,
+                                        keep = FALSE) {
+  do_join(x, y, by, copy, suffix, ..., keep = keep, join_type = "LEFT_SEMI")
+}
+semi_join.Dataset <- semi_join.ArrowTabular <- semi_join.arrow_dplyr_query
+
+anti_join.arrow_dplyr_query <- function(x,
+                                        y,
+                                        by = NULL,
+                                        copy = FALSE,
+                                        suffix = c(".x", ".y"),
+                                        ...,
+                                        keep = FALSE) {
+  do_join(x, y, by, copy, suffix, ..., keep = keep, join_type = "LEFT_ANTI")
+}
+anti_join.Dataset <- anti_join.ArrowTabular <- anti_join.arrow_dplyr_query
+
+handle_join_by <- function(by, x, y) {
+  if (is.null(by)) {
+    return(set_names(intersect(names(x), names(y))))
+  }
+  stopifnot(is.character(by))
+  if (is.null(names(by))) {
+    by <- set_names(by)
+  }
+  # TODO: nicer messages?
+  stopifnot(
+    all(names(by) %in% names(x)),
+    all(by %in% names(y))
+  )
+  by
+}