49 lines
2.1 KiB
Diff
49 lines
2.1 KiB
Diff
From 7d1394bd639e3bcf68082ac3fc33eeed6a00d2e6 Mon Sep 17 00:00:00 2001
|
|
From: Elly Fong-Jones <ellyjones@chromium.org>
|
|
Date: Thu, 2 Mar 2023 00:15:11 +0000
|
|
Subject: [PATCH] sql: relax constraints on VirtualCursor layout
|
|
|
|
VirtualCursor::FromSqliteCursor required that VirtualCursor had a
|
|
standard layout, but in fact VirtualCursor shouldn't have a standard
|
|
layout, and the fact that it does with libc++ is a deviation from the
|
|
C++ standard. This change:
|
|
|
|
1. Relaxes the requirement that VirtualCursor has a standard layout, and
|
|
2. Relaxes the requirement that the sqlite_cursor_ field has to be at
|
|
offset 0
|
|
|
|
by use of offsetof() and pointer subtraction. This change both improves
|
|
standards compliance and makes this code build with libstdc++.
|
|
|
|
Bug: 1380656
|
|
Change-Id: I9c47abd9197b187da0360ca5619ccf7dadab4f33
|
|
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4292313
|
|
Reviewed-by: Austin Sullivan <asully@chromium.org>
|
|
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
|
|
Cr-Commit-Position: refs/heads/main@{#1111925}
|
|
---
|
|
sql/recover_module/cursor.h | 10 ++++------
|
|
1 file changed, 4 insertions(+), 6 deletions(-)
|
|
|
|
diff --git a/sql/recover_module/cursor.h b/sql/recover_module/cursor.h
|
|
index 1970bdca8c6..4cb06557009 100644
|
|
--- a/sql/recover_module/cursor.h
|
|
+++ b/sql/recover_module/cursor.h
|
|
@@ -63,12 +63,10 @@ class VirtualCursor {
|
|
// |sqlite_cursor| must have been returned by VirtualTable::SqliteCursor().
|
|
static inline VirtualCursor* FromSqliteCursor(
|
|
sqlite3_vtab_cursor* sqlite_cursor) {
|
|
- static_assert(std::is_standard_layout<VirtualCursor>::value,
|
|
- "needed for the reinterpret_cast below");
|
|
- static_assert(offsetof(VirtualCursor, sqlite_cursor_) == 0,
|
|
- "sqlite_cursor_ must be the first member of the class");
|
|
- VirtualCursor* result = reinterpret_cast<VirtualCursor*>(sqlite_cursor);
|
|
- DCHECK_EQ(sqlite_cursor, &result->sqlite_cursor_);
|
|
+ VirtualCursor* result = reinterpret_cast<VirtualCursor*>(
|
|
+ (reinterpret_cast<char*>(sqlite_cursor) -
|
|
+ offsetof(VirtualCursor, sqlite_cursor_)));
|
|
+ CHECK_EQ(sqlite_cursor, &result->sqlite_cursor_);
|
|
return result;
|
|
}
|
|
|