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add locks for pdfium load

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We used to lock within documents, ie. we did not allow two threads to
work on the same file.

However pdfium is not threadsafe in any way, and this is not supported,
see:

	https://groups.google.com/forum/#!msg/pdfium/kyIdh_J4csg/K1LvfPiHDwAJ

This patch adds locks around pdfium calls.

see:

	https://github.com/libvips/libvips/issues/1380
	https://github.com/libvips/libvips/issues/1275
This commit is contained in:
John Cupitt 2019-08-08 15:54:16 +01:00
parent 675c150500
commit ff58c67e33
2 changed files with 30 additions and 0 deletions
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1
ChangeLog
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@ -5,6 +5,7 @@
- fix loop in malformed ppm [Kyle-Kyle]
- better support for PNGs with long comment names
- fix build with GM
- add locks for pdfium load
24/5/19 started 8.8.1
- improve realpath() use on older libc

29
libvips/foreign/pdfiumload.c
View File

@ -6,6 +6,8 @@
* - add background param
* 16/8/18
* - shut down the input file as soon as we can [kleisauke]
* 8/8/19
* - add locks, since pdfium is not threadsafe in any way
*/
/*
@ -139,8 +141,12 @@ vips_pdfium_error( void )
static void
vips_foreign_load_pdf_close( VipsForeignLoadPdf *pdf )
{
g_mutex_lock( vips__global_lock );
VIPS_FREEF( FPDF_ClosePage, pdf->page );
VIPS_FREEF( FPDF_CloseDocument, pdf->doc );
g_mutex_unlock( vips__global_lock );
}
static void
@ -209,6 +215,8 @@ vips_foreign_load_pdf_get_page( VipsForeignLoadPdf *pdf, int page_no )
if( pdf->current_page != page_no ) {
VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( pdf );
g_mutex_lock( vips__global_lock );
VIPS_FREEF( FPDF_ClosePage, pdf->page );
pdf->current_page = -1;
@ -217,12 +225,15 @@ vips_foreign_load_pdf_get_page( VipsForeignLoadPdf *pdf, int page_no )
#endif /*DEBUG*/
if( !(pdf->page = FPDF_LoadPage( pdf->doc, page_no )) ) {
g_mutex_unlock( vips__global_lock );
vips_pdfium_error();
vips_error( class->nickname,
_( "unable to load page %d" ), page_no );
return( -1 );
}
pdf->current_page = page_no;
g_mutex_unlock( vips__global_lock );
}
return( 0 );
@ -272,7 +283,9 @@ vips_foreign_load_pdf_set_image( VipsForeignLoadPdf *pdf, VipsImage *out )
char text[1024];
int len;
g_mutex_lock( vips__global_lock );
len = FPDF_GetMetaText( pdf->doc, metadata->tag, text, 1024 );
g_mutex_unlock( vips__global_lock );
if( len > 0 ) {
char *str;
@ -312,7 +325,9 @@ vips_foreign_load_pdf_header( VipsForeignLoad *load )
printf( "vips_foreign_load_pdf_header: %p\n", pdf );
#endif /*DEBUG*/
g_mutex_lock( vips__global_lock );
pdf->n_pages = FPDF_GetPageCount( pdf->doc );
g_mutex_unlock( vips__global_lock );
/* @n == -1 means until the end of the doc.
*/
@ -422,6 +437,8 @@ vips_foreign_load_pdf_generate( VipsRegion *or,
/* 4 means RGBA.
*/
g_mutex_lock( vips__global_lock );
bitmap = FPDFBitmap_CreateEx( rect.width, rect.height, 4,
VIPS_REGION_ADDR( or, rect.left, rect.top ),
VIPS_REGION_LSKIP( or ) );
@ -432,6 +449,8 @@ vips_foreign_load_pdf_generate( VipsRegion *or,
FPDFBitmap_Destroy( bitmap );
g_mutex_unlock( vips__global_lock );
top += rect.height;
i += 1;
}
@ -581,13 +600,18 @@ vips_foreign_load_pdf_file_header( VipsForeignLoad *load )
VipsForeignLoadPdf *pdf = (VipsForeignLoadPdf *) load;
VipsForeignLoadPdfFile *file = (VipsForeignLoadPdfFile *) load;
g_mutex_lock( vips__global_lock );
if( !(pdf->doc = FPDF_LoadDocument( file->filename, NULL )) ) {
g_mutex_unlock( vips__global_lock );
vips_pdfium_error();
vips_error( "pdfload",
_( "unable to load \"%s\"" ), file->filename );
return( -1 );
}
g_mutex_unlock( vips__global_lock );
VIPS_SETSTR( load->out->filename, file->filename );
return( vips_foreign_load_pdf_header( load ) );
@ -652,14 +676,19 @@ vips_foreign_load_pdf_buffer_header( VipsForeignLoad *load )
VipsForeignLoadPdfBuffer *buffer =
(VipsForeignLoadPdfBuffer *) load;
g_mutex_lock( vips__global_lock );
if( !(pdf->doc = FPDF_LoadMemDocument( buffer->buf->data,
buffer->buf->length, NULL )) ) {
g_mutex_unlock( vips__global_lock );
vips_pdfium_error();
vips_error( "pdfload",
"%s", _( "unable to load from buffer" ) );
return( -1 );
}
g_mutex_unlock( vips__global_lock );
return( vips_foreign_load_pdf_header( load ) );
}