add vips_image_set_blob_copy()

and use it where we can

ChangeLog

@@ -7,6 +7,7 @@
 - revise vips_cast() to improve behaviour with uint images [erdmann]
 - add bandand()/or()/eor() to cplusplus binding [clcaalu]
 - implement shrink-on-load for tiff pyramids [jcupitt]
+- added vips_image_set_blob_copy() [jcupitt]
 
 23/9/18 started 8.7.1
 - update function list in docs [janko-m] 

libvips/foreign/exif.c

@@ -447,22 +447,6 @@ vips_image_resolution_from_exif( VipsImage *image, ExifData *ed )
 	return( 0 );
 }
 
-static int
-vips_exif_get_thumbnail( VipsImage *im, ExifData *ed )
-{
-	if( ed->size > 0 ) {
-		char *thumb_copy;
-
-		thumb_copy = g_malloc( ed->size );      
-		memcpy( thumb_copy, ed->data, ed->size );
-
-		vips_image_set_blob( im, "jpeg-thumbnail-data", 
-			(VipsCallbackFn) g_free, thumb_copy, ed->size );
-	}
-
-	return( 0 );
-}
-
 /* Need to fwd ref this.
  */
 static int
@@ -516,7 +500,9 @@ vips__exif_parse( VipsImage *image )
 	exif_data_foreach_content( ed, 
 		(ExifDataForeachContentFunc) vips_exif_get_content, &params );
 
-	vips_exif_get_thumbnail( image, ed );
+	vips_image_set_blob_copy( image, 
+		"jpeg-thumbnail-data", ed->data, ed->size );
+
 	exif_data_free( ed );
 
 	/* Orientation handling. ifd0 has the Orientation tag for the main

libvips/foreign/jpeg2vips.c

@@ -309,8 +309,6 @@ find_chroma_subsample( struct jpeg_decompress_struct *cinfo )
 static int
 attach_blob( VipsImage *im, const char *field, void *data, int data_length )
 {
-	char *data_copy;
-
 	/* Only use the first one.
 	 */
 	if( vips_image_get_typeof( im, field ) ) {
@@ -325,11 +323,7 @@ attach_blob( VipsImage *im, const char *field, void *data, int data_length )
 	printf( "attach_blob: attaching %d bytes of %s\n", data_length, field );
 #endif /*DEBUG*/
 
-	if( !(data_copy = vips_malloc( NULL, data_length )) )
+	vips_image_set_blob_copy( im, field, data, data_length );
-		return( -1 );
-	memcpy( data_copy, data, data_length );
-	vips_image_set_blob( im, field, 
-		(VipsCallbackFn) vips_free, data_copy, data_length );
 
 	return( 0 );
 }

libvips/foreign/niftiload.c

@@ -500,14 +500,9 @@ vips_foreign_load_nifti_set_header( VipsForeignLoadNifti *nifti,
 
 	for( i = 0; i < nim->num_ext; i++ ) {
 		nifti1_extension *ext = &nim->ext_list[i];
-		char *data_copy;
 
 		vips_snprintf( txt, 256, "nifti-ext-%d-%d", i, ext->ecode );
-		if( !(data_copy = vips_malloc( NULL, ext->esize )) )
+		vips_image_set_blob_copy( out, txt, ext->edata, ext->esize );
-			return( -1 );
-		memcpy( data_copy, ext->edata, ext->esize );
-		vips_image_set_blob( out, txt, 
-			(VipsCallbackFn) vips_free, data_copy, ext->esize );
 	}
 
 	if( nim->ny > 1 )

libvips/foreign/tiff2vips.c

@@ -1353,43 +1353,37 @@ rtiff_set_header( Rtiff *rtiff, VipsImage *out )
 	 */
 	if( TIFFGetField( rtiff->tiff, 
 		TIFFTAG_ICCPROFILE, &data_length, &data ) ) {
-		if( vips_image_set_blob_copy( rtiff, out, 
+		vips_image_set_blob_copy( out, 
-			VIPS_META_ICC_NAME, data_length, data ) )
+			VIPS_META_ICC_NAME, data, data_length );
-			return( -1 );
 	}
 
 	/* Read any XMP metadata.
 	 */
 	if( TIFFGetField( rtiff->tiff, 
 		TIFFTAG_XMLPACKET, &data_length, &data ) ) {
-		if( vips_image_set_blob_copy( rtiff, out, 
+		vips_image_set_blob_copy( out, 
-			VIPS_META_XMP_NAME, data_length, data ) )
+			VIPS_META_XMP_NAME, data, data_length );
-			return( -1 );
 	}
 
 	/* Read any IPTC metadata.
 	 */
 	if( TIFFGetField( rtiff->tiff, 
 		TIFFTAG_RICHTIFFIPTC, &data_length, &data ) ) {
-		if( vips_image_set_blob_copy( rtiff, out, 
+		vips_image_set_blob_copy( out, 
-			VIPS_META_IPTC_NAME, data_length, data ) )
+			VIPS_META_IPTC_NAME, data, data_length );
-			return( -1 );
 
 		/* Older versions of libvips used this misspelt name :-( attach 
 		 * under this name too for compatibility.
 		 */
-		if( vips_image_set_blob_copy( rtiff, out, 
+		vips_image_set_blob_copy( out, "ipct-data", data, data_length );
-			"ipct-data", data_length, data ) )
-			return( -1 );
 	}
 
 	/* Read any photoshop metadata.
 	 */
 	if( TIFFGetField( rtiff->tiff, 
 		TIFFTAG_PHOTOSHOP, &data_length, &data ) ) {
-		if( vips_image_set_blob_copy( rtiff, out, 
+		vips_image_set_blob_copy( out, 
-			VIPS_META_PHOTOSHOP_NAME, data_length, data ) )
+			VIPS_META_PHOTOSHOP_NAME, data, data_length );
-			return( -1 );
 	}
 
 	/* IMAGEDESCRIPTION often has useful metadata.

libvips/foreign/vipspng.c

@@ -448,19 +448,14 @@ png2vips_header( Read *read, VipsImage *out )
 	 */
 	if( png_get_iCCP( read->pPng, read->pInfo, 
 		&name, &compression_type, &profile, &proflen ) ) {
-		void *profile_copy;
-
 #ifdef DEBUG
 		printf( "png2vips_header: attaching %d bytes of ICC profile\n",
 			proflen );
 		printf( "png2vips_header: name = \"%s\"\n", name );
 #endif /*DEBUG*/
 
-		if( !(profile_copy = vips_malloc( NULL, proflen )) ) 
+		vips_image_set_blob_copy( out, 
-			return( -1 );
+			VIPS_META_ICC_NAME, profile, proflen );
-		memcpy( profile_copy, profile, proflen );
-		vips_image_set_blob( out, VIPS_META_ICC_NAME, 
-			(VipsCallbackFn) vips_free, profile_copy, proflen );
 	}
 
 	/* Sanity-check line size.

libvips/foreign/webp2vips.c

@@ -254,18 +254,9 @@ read_header( Read *read, VipsImage *out )
 
 		WebPData data;
 
-		if( WebPMuxGetChunk( mux, webp, &data ) == WEBP_MUX_OK ) { 
+		if( WebPMuxGetChunk( mux, webp, &data ) == WEBP_MUX_OK )  
-			void *blob;
+			vips_image_set_blob_copy( out, 
-
+				vips, data.bytes, data.size );
-			if( !(blob = vips_malloc( NULL, data.size )) ) {
-				WebPMuxDelete( mux ); 
-				return( -1 ); 
-			}
-
-			memcpy( blob, data.bytes, data.size );
-			vips_image_set_blob( out, vips, 
-				(VipsCallbackFn) vips_free, blob, data.size );
-		}
 	}
 
 	WebPMuxDelete( mux ); 

libvips/include/vips/header.h

@@ -196,7 +196,7 @@ int vips_image_get_area( const VipsImage *image,
 void vips_image_set_blob( VipsImage *image, 
 	const char *name, VipsCallbackFn free_fn, void *data, size_t length );
 void vips_image_set_blob_copy( VipsImage *image, 
-	const char *name, void *data, size_t length );
+	const char *name, const void *data, size_t length );
 int vips_image_get_blob( const VipsImage *image, const char *name, 
 	void **data, size_t *length );
 

libvips/iofuncs/header.c

@@ -27,7 +27,7 @@
  * 	- vips_image_get_*() all convert everything to target type if they can
  * 	- rename "field" as "name" in docs
  * 21/11/18
- * 	- get_string will allow BLOB, G_STRING and REF_STRING
+ * 	- get_string will allow G_STRING and REF_STRING
  */
 
 /*
@@ -1368,60 +1368,32 @@ vips_image_set_blob( VipsImage *image,
  * @length: length of memory area
  *
  * Attaches @blob as a metadata item on @image under the name @name, taking
- * a copy of the memory area. A convenience function over vips_image_set_blob().
+ * a copy of the memory area. A convenience function over 
- *
+ * vips_image_set_blob().
- * One more byte is allocated and a secret null added to the end, although
- * this extra length is not recorded. This makes reading the value out later
- * as a C string safer and more convenient.
  *
  * See also: vips_image_get_blob(), vips_image_set().
  */
 void
 vips_image_set_blob_copy( VipsImage *image, 
-	const char *name, void *data, size_t length )
+	const char *name, const void *data, size_t length )
 {
 	void *data_copy;
 
 	if( !data ||
 		length == 0 )
-		return( 0 );
+		return;
 
+	/* We add an extra, secret null byte at the end, just in case this blob 
+	 * is read as a C string. The libtiff reader (for example) attaches
+	 * XMP XML as a blob, for example.
+	 */
 	if( !(data_copy = vips_malloc( NULL, length + 1 )) ) 
-		return( -1 );
+		return;
 	memcpy( data_copy, data, length );
 	((unsigned char *) data_copy)[length] = '\0';
 
-	vips_image_set_blob( out, field, 
+	vips_image_set_blob( image, 
-		(VipsCallbackFn) vips_free, data_copy, length );
+		name, (VipsCallbackFn) vips_free, data_copy, length );
-
-	return( 0 );
-}
-
-/* Set a blob on an image from a libtiff pointer/length. We don't null
- * terminate, even though most of these things are strings, because we want to
- * be able to write them back unaltered.
- *
- * Null-termination, checking for utf-8, checking for embedded null characters
- * etc. must all be done on readout from the blob.
- */
-static int
-rtiff_set_blob( Rtiff *rtiff, VipsImage *out, const char *field,
-	uint32 data_length, unsigned char *data )
-{
-	unsigned char *data_copy;
-
-	if( !data ||
-		data_length == 0 )
-		return( 0 );
-
-	if( !(data_copy = vips_malloc( NULL, data_length )) ) 
-		return( -1 );
-	memcpy( data_copy, data, data_length );
-
-	vips_image_set_blob( out, field, 
-		(VipsCallbackFn) vips_free, data_copy, data_length );
-
-	return( 0 );
 }
 
 /** 
@@ -1564,8 +1536,7 @@ vips_image_set_double( VipsImage *image, const char *name, double d )
  *
  * Gets @out from @im under the name @name. 
  * The field must be of type
- * G_STRING, VIPS_TYPE_REFSTRING or VIPS_TYPE_BLOB. If it's a BLOB, it must be
+ * G_STRING, VIPS_TYPE_REFSTRING.
- * null-terminated. 
  *
  * Do not free @out.
  *
@@ -1583,24 +1554,8 @@ vips_image_get_string( const VipsImage *image, const char *name,
 
 	if( vips_image_get( image, name, &value ) )
 		return( -1 );
-	if( G_VALUE_TYPE( &value ) == VIPS_TYPE_BLOB ) {
-		char *str;
-		size_t length;
 
-		str = vips_value_get_blob( &value, &length );
+	if( G_VALUE_TYPE( &value ) == VIPS_TYPE_REF_STRING ) {
-		if( length <= 0 ||
-			str[length] != '\0' ) {
-			g_value_unset( &value );
-			vips_error( "VipsImage",
-				_( "field \"%s\" is not null-terminated" ),
-				name );
-
-			return( -1 );
-		}
-
-		*out = str;
-	}
-	else if( G_VALUE_TYPE( &value ) == VIPS_TYPE_REF_STRING ) {
 		VipsArea *area;
 
 		area = g_value_get_boxed( &value );