tree 8468101742083dcc040e4df893c6268210485cad
parent 16d6eb8b6204a91bc40b9431ba31a9503169b00b
author Lei Zhang <thestig@chromium.org> 1693245245 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> 1693245245 +0000

Prevent crashes in win32 GDI code due to null bitmap pointers

This CL adds CFX_DIBBase::RealizeIfNeeded() as the spiritial successor
to CFX_DIBExtractor, which https://pdfium-review.googlesource.com/108371
removed. This is necessary for interactions with some GDI APIs that do
not operate on scanlines and require a pointer to a contiguous bitmap
buffer.

Call RealizeIfNeeded() closer to where the GDI API calls happen, instead
of exactly where the prior CFX_DIBExtractor uses were. With the
RealizeIfNeeded() calls in place, the GDI APIs will no longer receive
null buffer pointers and crash.

Unlike CFX_DIBExtractor, RealizeIfNeeded() won't create a new
CFX_DIBitmap when an existing CFX_DIBBase already has a contiguous
buffer.

Bug: chromium:1466498
Change-Id: I33b46a79c2f0a2ad467e40171db328c4f74b8153
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/111433
Commit-Queue: Nigi <nigi@chromium.org>
Reviewed-by: Nigi <nigi@chromium.org>