1 files changed, 195 insertions, 0 deletions
diff --git a/src/arrow/r/R/util.R b/src/arrow/r/R/util.R
new file mode 100644
index 000000000..9e3ade6a9
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+++ b/src/arrow/r/R/util.R
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+# 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.
+
+# for compatibility with R versions earlier than 4.0.0
+if (!exists("deparse1")) {
+  deparse1 <- function(expr, collapse = " ", width.cutoff = 500L, ...) {
+    paste(deparse(expr, width.cutoff, ...), collapse = collapse)
+  }
+}
+
+# for compatibility with R versions earlier than 3.6.0
+if (!exists("str2lang")) {
+  str2lang <- function(s) {
+    parse(text = s, keep.source = FALSE)[[1]]
+  }
+}
+
+oxford_paste <- function(x, conjunction = "and", quote = TRUE) {
+  if (quote && is.character(x)) {
+    x <- paste0('"', x, '"')
+  }
+  if (length(x) < 2) {
+    return(x)
+  }
+  x[length(x)] <- paste(conjunction, x[length(x)])
+  if (length(x) > 2) {
+    return(paste(x, collapse = ", "))
+  } else {
+    return(paste(x, collapse = " "))
+  }
+}
+
+assert_is <- function(object, class) {
+  msg <- paste(substitute(object), "must be a", oxford_paste(class, "or"))
+  assert_that(inherits(object, class), msg = msg)
+}
+
+assert_is_list_of <- function(object, class) {
+  msg <- paste(substitute(object), "must be a list of", oxford_paste(class, "or"))
+  assert_that(is_list_of(object, class), msg = msg)
+}
+
+is_list_of <- function(object, class) {
+  is.list(object) && all(map_lgl(object, ~ inherits(., class)))
+}
+
+empty_named_list <- function() structure(list(), .Names = character(0))
+
+r_symbolic_constants <- c(
+  "pi", "TRUE", "FALSE", "NULL", "Inf", "NA", "NaN",
+  "NA_integer_", "NA_real_", "NA_complex_", "NA_character_"
+)
+
+is_function <- function(expr, name) {
+  # We could have a quosure here if we have an expression like `sum({{ var }})`
+  if (is_quosure(expr)) {
+    expr <- quo_get_expr(expr)
+  }
+  if (!is.call(expr)) {
+    return(FALSE)
+  } else {
+    if (deparse(expr[[1]]) == name) {
+      return(TRUE)
+    }
+    out <- lapply(expr, is_function, name)
+  }
+  any(map_lgl(out, isTRUE))
+}
+
+all_funs <- function(expr) {
+  # It is not sufficient to simply do: setdiff(all.names, all.vars)
+  # here because that would fail to return the names of functions that
+  # share names with variables.
+  # To preserve duplicates, call `all.names()` not `all_names()` here.
+  if (is_quosure(expr)) {
+    expr <- quo_get_expr(expr)
+  }
+  names <- all.names(expr)
+  names[map_lgl(names, ~ is_function(expr, .))]
+}
+
+all_vars <- function(expr) {
+  setdiff(all.vars(expr), r_symbolic_constants)
+}
+
+all_names <- function(expr) {
+  setdiff(all.names(expr), r_symbolic_constants)
+}
+
+is_constant <- function(expr) {
+  length(all_vars(expr)) == 0
+}
+
+read_compressed_error <- function(e) {
+  msg <- conditionMessage(e)
+  if (grepl(" codec ", msg)) {
+    compression <- sub(".*Support for codec '(.*)'.*", "\\1", msg)
+    e$message <- paste0(
+      msg,
+      "\nIn order to read this file, you will need to reinstall arrow with additional features enabled.",
+      "\nSet one of these environment variables before installing:",
+      sprintf("\n\n * LIBARROW_MINIMAL=false (for all optional features, including '%s')", compression),
+      sprintf("\n * ARROW_WITH_%s=ON (for just '%s')", toupper(compression), compression),
+      "\n\nSee https://arrow.apache.org/docs/r/articles/install.html for details"
+    )
+  }
+  stop(e)
+}
+
+handle_parquet_io_error <- function(e, format) {
+  msg <- conditionMessage(e)
+  if (grepl("Parquet magic bytes not found in footer", msg) && length(format) > 1 && is_character(format)) {
+    # If length(format) > 1, that means it is (almost certainly) the default/not specified value
+    # so let the user know that they should specify the actual (not parquet) format
+    abort(c(
+      msg,
+      i = "Did you mean to specify a 'format' other than the default (parquet)?"
+    ))
+  }
+  stop(e)
+}
+
+is_writable_table <- function(x) {
+  inherits(x, c("data.frame", "ArrowTabular"))
+}
+
+# This attribute is used when is_writable is passed into assert_that, and allows
+# the call to form part of the error message when is_writable is FALSE
+attr(is_writable_table, "fail") <- function(call, env) {
+  paste0(
+    deparse(call$x),
+    " must be an object of class 'data.frame', 'RecordBatch', or 'Table', not '",
+    class(env[[deparse(call$x)]])[[1]],
+    "'."
+  )
+}
+
+#' Recycle scalar values in a list of arrays
+#'
+#' @param arrays List of arrays
+#' @return List of arrays with any vector/Scalar/Array/ChunkedArray values of length 1 recycled
+#' @keywords internal
+recycle_scalars <- function(arrays) {
+  # Get lengths of items in arrays
+  arr_lens <- map_int(arrays, NROW)
+
+  is_scalar <- arr_lens == 1
+
+  if (length(arrays) > 1 && any(is_scalar) && !all(is_scalar)) {
+
+    # Recycling not supported for tibbles and data.frames
+    if (all(map_lgl(arrays, ~ inherits(.x, "data.frame")))) {
+      abort(c(
+        "All input tibbles or data.frames must have the same number of rows",
+        x = paste(
+          "Number of rows in longest and shortest inputs:",
+          oxford_paste(c(max(arr_lens), min(arr_lens)))
+        )
+      ))
+    }
+
+    max_array_len <- max(arr_lens)
+    arrays[is_scalar] <- lapply(arrays[is_scalar], repeat_value_as_array, max_array_len)
+  }
+  arrays
+}
+
+#' Take an object of length 1 and repeat it.
+#'
+#' @param object Object of length 1 to be repeated - vector, `Scalar`, `Array`, or `ChunkedArray`
+#' @param n Number of repetitions
+#'
+#' @return `Array` of length `n`
+#'
+#' @keywords internal
+repeat_value_as_array <- function(object, n) {
+  if (inherits(object, "ChunkedArray")) {
+    return(Scalar$create(object$chunks[[1]])$as_array(n))
+  }
+  return(Scalar$create(object)$as_array(n))
+}