Internal PDF import spends forever on ICC color space parsing

Summary:

I have a CorelDraw generated PDF file which takes about 10 seconds to load with "Poppler/Cairo import" method, but takes forever with "Internal import" method. Random interruptions of the process indicate that most of the time is spend for ICC color space parsing. For example:

#0  0x00007ffff54db495 in FlateStream::readSome() () at /usr/lib/libpoppler.so.102
#1  0x00007ffff54db703 in FlateStream::getChars(int, unsigned char*) () at /usr/lib/libpoppler.so.102
#2  0x00007ffff54843b3 in GfxICCBasedColorSpace::parse(Array*, OutputDev*, GfxState*, int) () at /usr/lib/libpoppler.so.102
#3  0x00007ffff5485db8 in GfxColorSpace::parse(GfxResources*, Object*, OutputDev*, GfxState*, int) () at /usr/lib/libpoppler.so.102
#4  0x00007ffff6f2ea8a in PdfParser::opSetFillColorSpace(Object*, int) (this=0x555556bacf40, args=0x7fffffffda90) at ../src/extension/internal/pdfinput/pdf-parser.cpp:1094

There are only 5 color spaces defined in the file, caching the result of GfxColorSpace::parse would fix the problem.

Steps to reproduce:

• open Inkscape
• File > Open... > select PDF with many ICC color space references
• Keep default PDF import settings, in particular "Internal import"
• Click OK

What happened?

Inkscape freezes

What should have happened?

Import time should be comparable to Poppler/Cairo method.

Inkscape Version and Operating System:

• Inkscape Version: 1.1-dev (97c5de14bd, 2020-09-20, custom)
• Operating System: Arch Linux