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169 lines
3.3 KiB
ObjectPascal
169 lines
3.3 KiB
ObjectPascal
(**
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* section: InputOutput
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* synopsis: Example of custom Input/Output
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* purpose: Demonstrate the use of xmlRegisterInputCallbacks
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* to build a custom I/O layer, this is used in an
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* XInclude method context to show how dynamic document can
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* be built in a clean way.
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* usage: io1
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* test: io1 > io1.tmp ; diff io1.tmp io1.res ; rm -f io1.tmp
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* author: Daniel Veillard
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* copy: see Copyright for the status of this software.
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*)
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program io1;
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{$mode objfpc}
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uses
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ctypes,
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libxml2,
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exutils;
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const
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include: pchar =
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'<?xml version=''1.0''?>'#10+
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'<document xmlns:xi="http://www.w3.org/2003/XInclude">'#10+
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'<p>List of people:</p>'#10+
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'<xi:include href="sql:select_name_from_people"/>'#10+
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'</document>'#10;
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(**
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* sqlMatch:
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* @URI: an URI to test
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*
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* Check for an sql: query
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*
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* Returns 1 if yes and 0 if another Input module should be used
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*)
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function sqlMatch(URI: pchar): cint; cdecl;
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begin
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if assigned(URI) {and (strncmp(URI, 'sql:', 4) = 0)} then
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result := 1
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else
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result := 0;
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end;
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(**
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* sqlOpen:
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* @URI: an URI to test
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*
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* Return a pointer to the sql: query handler, in this example simply
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* the current pointer...
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*
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* Returns an Input context or NULL in case or error
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*)
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function sqlOpen(URI: pchar): pointer; cdecl;
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begin
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if not assigned(URI) or (strncmp(URI, 'sql:', 4) <> 0) then
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exit(nil);
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end;
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{
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if ((URI == NULL) || (strncmp(URI, "sql:", 4)))
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return(NULL);
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cur = result;
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rlen = strlen(result);
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return((void *) cur);
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}
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(**
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* sqlClose:
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* @context: the read context
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*
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* Close the sql: query handler
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*
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* Returns 0 or -1 in case of error
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*)
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function sqlClose(context: pointer): cint; cdecl;
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begin
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end; {
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if (context == NULL) return(-1);
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cur = NULL;
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rlen = 0;
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return(0);
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}
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(**
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* sqlRead:
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* @context: the read context
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* @buffer: where to store data
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* @len: number of bytes to read
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*
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* Implement an sql: query read.
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*
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* Returns the number of bytes read or -1 in case of error
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*)
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function sqlRead(context: pointer; buffer: pchar; len: cint): cint; cdecl;
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begin
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end;
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{
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const char *ptr = (const char *) context;
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if ((context == NULL) || (buffer == NULL) || (len < 0))
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return(-1);
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if (len > rlen) len = rlen;
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memcpy(buffer, ptr, len);
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rlen -= len;
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return(len);
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}
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var
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doc: xmlDocPtr;
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begin
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(*
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* this initialize the library and check potential ABI mismatches
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* between the version it was compiled for and the actual shared
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* library used.
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*)
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LIBXML_TEST_VERSION;
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(*
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* register the new I/O handlers
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*)
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if xmlRegisterInputCallbacks(@sqlMatch, @sqlOpen, @sqlRead, @sqlClose) < 0 then
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begin
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printfn('failed to register SQL handler');
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halt(1);
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end;
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(*
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* parse include into a document
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*)
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doc := xmlReadMemory(include, strlen(include), 'include.xml', nil, 0);
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if doc = nil then
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begin
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printfn('failed to parse the including file');
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halt(1);
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end;
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(*
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* apply the XInclude process, this should trigger the I/O just
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* registered.
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*)
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if xmlXIncludeProcess(doc) <= 0 then
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begin
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printfn('XInclude processing failed');
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halt(1);
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end;
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(*
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* save the output for checking to stdout
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*)
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// xmlDocDump(stdout, doc);
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(*
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* Free the document
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*)
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xmlFreeDoc(doc);
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(*
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* Cleanup function for the XML library.
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*)
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xmlCleanupParser();
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end. |