From 9599051bc7dbf9a3483cb20891c76acebbcd8691 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <antoine@python.org>
Date: Thu, 1 Dec 2022 19:35:53 +0100
Subject: [PATCH] DRAFT: [C++] C Data Interface: check imported buffer for
 non-null

Followup to https://github.com/apache/arrow/issues/14805
---
 cpp/src/arrow/c/bridge.cc | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/cpp/src/arrow/c/bridge.cc b/cpp/src/arrow/c/bridge.cc
index 002096399d261..2cbef53226a69 100644
--- a/cpp/src/arrow/c/bridge.cc
+++ b/cpp/src/arrow/c/bridge.cc
@@ -1528,7 +1528,7 @@ struct ArrayImporter {
   }
 
   Status ImportNullBitmap(int32_t buffer_id = 0) {
-    RETURN_NOT_OK(ImportBitsBuffer(buffer_id));
+    RETURN_NOT_OK(ImportBitsBuffer(buffer_id, /*is_null_bitmap=*/true));
     if (data_->null_count > 0 && data_->buffers[buffer_id] == nullptr) {
       return Status::Invalid(
           "ArrowArray struct has null bitmap buffer but non-zero null_count ",
@@ -1537,10 +1537,10 @@ struct ArrayImporter {
     return Status::OK();
   }
 
-  Status ImportBitsBuffer(int32_t buffer_id) {
+  Status ImportBitsBuffer(int32_t buffer_id, bool is_null_bitmap = false) {
     // Compute visible size of buffer
     int64_t buffer_size = bit_util::BytesForBits(c_struct_->length + c_struct_->offset);
-    return ImportBuffer(buffer_id, buffer_size);
+    return ImportBuffer(buffer_id, buffer_size, is_null_bitmap);
   }
 
   Status ImportFixedSizeBuffer(int32_t buffer_id, int64_t byte_width) {
@@ -1566,13 +1566,19 @@ struct ArrayImporter {
     return ImportBuffer(buffer_id, buffer_size);
   }
 
-  Status ImportBuffer(int32_t buffer_id, int64_t buffer_size) {
+  Status ImportBuffer(int32_t buffer_id, int64_t buffer_size,
+                      bool is_null_bitmap = false) {
     std::shared_ptr<Buffer>* out = &data_->buffers[buffer_id];
     auto data = reinterpret_cast<const uint8_t*>(c_struct_->buffers[buffer_id]);
     if (data != nullptr) {
       *out = std::make_shared<ImportedBuffer>(data, buffer_size, import_);
     } else {
       out->reset();
+      if (!is_null_bitmap && buffer_size != 0) {
+        return Status::Invalid(
+            "ArrowArrayStruct contains null data pointer "
+            "for a buffer with non-zero computed size");
+      }
     }
     return Status::OK();
   }