1 | // |
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2 | // EntityResolver.h |
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3 | // |
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4 | // $Id: //poco/1.3/XML/include/Poco/SAX/EntityResolver.h#1 $ |
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5 | // |
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6 | // Library: XML |
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7 | // Package: SAX |
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8 | // Module: SAX |
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9 | // |
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10 | // SAX EntityResolver Interface. |
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11 | // |
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12 | // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH. |
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13 | // and Contributors. |
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14 | // |
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15 | // Permission is hereby granted, free of charge, to any person or organization |
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16 | // obtaining a copy of the software and accompanying documentation covered by |
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17 | // this license (the "Software") to use, reproduce, display, distribute, |
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18 | // execute, and transmit the Software, and to prepare derivative works of the |
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19 | // Software, and to permit third-parties to whom the Software is furnished to |
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20 | // do so, all subject to the following: |
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21 | // |
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22 | // The copyright notices in the Software and this entire statement, including |
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23 | // the above license grant, this restriction and the following disclaimer, |
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24 | // must be included in all copies of the Software, in whole or in part, and |
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25 | // all derivative works of the Software, unless such copies or derivative |
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26 | // works are solely in the form of machine-executable object code generated by |
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27 | // a source language processor. |
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28 | // |
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29 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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30 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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31 | // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT |
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32 | // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE |
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33 | // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, |
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34 | // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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35 | // DEALINGS IN THE SOFTWARE. |
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36 | // |
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37 | |
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38 | |
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39 | #ifndef SAX_EntityResolver_INCLUDED |
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40 | #define SAX_EntityResolver_INCLUDED |
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41 | |
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42 | |
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43 | #include "Poco/XML/XML.h" |
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44 | #include "Poco/XML/XMLString.h" |
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45 | |
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46 | |
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47 | namespace Poco { |
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48 | namespace XML { |
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49 | |
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50 | |
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51 | class InputSource; |
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52 | |
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53 | |
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54 | class XML_API EntityResolver |
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55 | /// If a SAX application needs to implement customized handling for external entities, |
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56 | /// it must implement this interface and register an instance with the SAX driver using |
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57 | /// the setEntityResolver method. |
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58 | /// |
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59 | /// The XML reader will then allow the application to intercept any external entities |
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60 | /// (including the external DTD subset and external parameter entities, if any) before |
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61 | /// including them. |
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62 | /// |
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63 | /// Many SAX applications will not need to implement this interface, but it will be |
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64 | /// especially useful for applications that build XML documents from databases or other |
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65 | /// specialised input sources, or for applications that use URI types other than URLs. |
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66 | /// |
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67 | /// The application can also use this interface to redirect system identifiers to local |
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68 | /// URIs or to look up replacements in a catalog (possibly by using the public identifier). |
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69 | { |
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70 | public: |
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71 | virtual InputSource* resolveEntity(const XMLString* publicId, const XMLString& systemId) = 0; |
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72 | /// Allow the application to resolve external entities. |
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73 | /// |
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74 | /// The parser will call this method before opening any external entity except the |
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75 | /// top-level document entity. Such entities include the external DTD subset and |
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76 | /// external parameter entities referenced within the DTD (in either case, only |
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77 | /// if the parser reads external parameter entities), and external general entities |
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78 | /// referenced within the document element (if the parser reads external general entities). |
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79 | /// The application may request that the parser locate the entity itself, that it use an |
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80 | /// alternative URI, or that it use data provided by the application (as a character or |
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81 | /// byte input stream). |
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82 | /// |
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83 | /// Application writers can use this method to redirect external system identifiers to |
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84 | /// secure and/or local URIs, to look up public identifiers in a catalogue, or to read an |
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85 | /// entity from a database or other input source (including, for example, a dialog box). |
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86 | /// Neither XML nor SAX specifies a preferred policy for using public or system IDs to resolve |
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87 | /// resources. However, SAX specifies how to interpret any InputSource returned by this method, |
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88 | /// and that if none is returned, then the system ID will be dereferenced as a URL. |
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89 | /// |
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90 | /// If the system identifier is a URL, the SAX parser must resolve it fully before reporting it to |
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91 | /// the application. |
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92 | /// |
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93 | /// Note that publicId maybe null, therefore we pass a pointer rather than a reference. |
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94 | |
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95 | virtual void releaseInputSource(InputSource* pSource) = 0; |
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96 | /// This is a non-standard extension to SAX! |
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97 | /// Called by the parser when the input source returned by ResolveEntity is |
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98 | /// no longer needed. Should free any resources used by the input source. |
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99 | |
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100 | protected: |
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101 | virtual ~EntityResolver(); |
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102 | }; |
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103 | |
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104 | |
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105 | } } // namespace Poco::XML |
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106 | |
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107 | |
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108 | #endif // SAX_EntityResolver_INCLUDED |
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