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21
22 #ifndef INCLUDED_SVGIO_LINKEDIMAGEPOLICY_HXX
23 #define INCLUDED_SVGIO_LINKEDIMAGEPOLICY_HXX
24
25 #include "sal/config.h"
26
27 #include "rtl/uri.hxx"
28 #include "rtl/ustring.hxx"
29 #include "svtools/linkpolicy.hxx"
30
31 namespace svgio { namespace svgreader {
32
33 /** Resolves an <image> reference against the SVG's own location and decides
34 whether it may be opened.
35
36 An <image> href is document content, read while the SVG is decomposed. The
37 reference is only followed when it stays with the SVG: the feature it
38 exists for is an image delivered alongside the file (a relative href), so
39 a target that resolves to some other place on the machine, to another
40 host, or into a different scheme is not part of that feature and is
41 refused.
42
43 Nothing here needs a document or a service: the decision is made from the
44 two strings, so it holds the same way on every route that reaches the
45 decompose step, and for a base URL that is itself remote (a remote base
46 contains no local files, so every local target falls outside it).
47
48 @param rBase
49 the SVG's own absolute location, as the document reports it.
50
51 @param rHref
52 the reference as it was written in the file, relative or absolute.
53
54 @param rAbsoluteUrl
55 on success, the resolved URL to open; untouched otherwise.
56
57 @return true when the reference may be opened.
58 */
resolveLinkedImageUrl(::rtl::OUString const & rBase,::rtl::OUString const & rHref,::rtl::OUString & rAbsoluteUrl)59 inline bool resolveLinkedImageUrl(
60 ::rtl::OUString const & rBase,
61 ::rtl::OUString const & rHref,
62 ::rtl::OUString & rAbsoluteUrl )
63 {
64 if ( rBase.getLength() == 0 || rHref.getLength() == 0 )
65 return false;
66
67 // A malformed base makes the reference unresolvable. convertRelToAbs
68 // signals that by throwing, and the throw must not leave the decompose
69 // call -- it would cross a UNO interface that does not declare it.
70 ::rtl::OUString aAbsUrl;
71 try
72 {
73 aAbsUrl = ::rtl::Uri::convertRelToAbs( rBase, rHref );
74 }
75 catch ( const ::rtl::MalformedUriException & )
76 {
77 return false;
78 }
79 if ( aAbsUrl.getLength() == 0 )
80 return false;
81
82 // This is opened as a plain file, so a file: reference on this machine is
83 // the only thing that can be read here; the test also refuses the schemes
84 // that address process state and a UNC reference to another host.
85 if ( !::svt::linkpolicy::isLocalFileUrl( aAbsUrl ) )
86 return false;
87
88 // ... and only where the SVG itself sits.
89 if ( !::svt::linkpolicy::isContainedUnder( rBase, aAbsUrl ) )
90 return false;
91
92 rAbsoluteUrl = aAbsUrl;
93 return true;
94 }
95
96 } }
97
98 #endif
99