parent
c76bdb2f62
commit
7ee55adb85
@ -0,0 +1,375 @@
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# erAck: backport of expat CVE-2023-52425 DoS fix
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# https://github.com/libexpat/libexpat/commit/34b598c5f594b015c513c73f06e7ced3323edbf1
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#
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--- firefox-115.9.0/parser/expat/lib/expat.h.expat-CVE-2023-52425 2024-03-11 20:36:11.000000000 +0100
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+++ firefox-115.9.0/parser/expat/lib/expat.h 2024-03-13 20:46:45.648505015 +0100
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@@ -1045,6 +1045,10 @@ XMLPARSEAPI(const XML_Feature *)
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XML_GetFeatureList(void);
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+/* Added in Expat 2.6.0. */
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+XMLPARSEAPI(XML_Bool)
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+XML_SetReparseDeferralEnabled(XML_Parser parser, XML_Bool enabled);
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+
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/* Expat follows the semantic versioning convention.
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See http://semver.org.
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*/
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--- firefox-115.9.0/parser/expat/lib/internal.h.expat-CVE-2023-52425 2024-03-11 20:36:11.000000000 +0100
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+++ firefox-115.9.0/parser/expat/lib/internal.h 2024-03-14 00:14:39.334319725 +0100
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@@ -80,6 +80,7 @@
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# endif
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#endif
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+#include "expat.h" // so we can use type XML_Parser below
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#ifdef __cplusplus
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extern "C" {
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@@ -90,6 +91,9 @@ void
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align_limit_to_full_utf8_characters(const char * from, const char ** fromLimRef);
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+extern XML_Bool g_reparseDeferralEnabledDefault; // written ONLY in runtests.c
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+extern unsigned int g_parseAttempts; // used for testing only
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+
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#ifdef __cplusplus
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}
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#endif
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--- firefox-115.9.0/parser/expat/lib/xmlparse.c.expat-CVE-2023-52425 2024-03-11 20:36:11.000000000 +0100
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+++ firefox-115.9.0/parser/expat/lib/xmlparse.c 2024-03-13 22:55:14.844756009 +0100
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@@ -6,6 +6,7 @@
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#define _GNU_SOURCE /* syscall prototype */
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+#include <stdbool.h>
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#include <stddef.h>
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#include <string.h> /* memset(), memcpy() */
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#include <assert.h>
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@@ -89,6 +90,9 @@ typedef char ICHAR;
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/* Round up n to be a multiple of sz, where sz is a power of 2. */
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#define ROUND_UP(n, sz) (((n) + ((sz) - 1)) & ~((sz) - 1))
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+/* Do safe (NULL-aware) pointer arithmetic */
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+#define EXPAT_SAFE_PTR_DIFF(p, q) (((p) && (q)) ? ((p) - (q)) : 0)
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+
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/* Handle the case where memmove() doesn't exist. */
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#ifndef HAVE_MEMMOVE
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#ifdef HAVE_BCOPY
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@@ -98,6 +102,8 @@ typedef char ICHAR;
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#endif /* HAVE_BCOPY */
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#endif /* HAVE_MEMMOVE */
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+#define EXPAT_MIN(a, b) (((a) < (b)) ? (a) : (b))
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+
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#include "internal.h"
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#include "xmltok.h"
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#include "xmlrole.h"
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@@ -476,6 +482,9 @@ parserInit(XML_Parser parser, const XML_
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? 0 \
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: ((*((pool)->ptr)++ = c), 1))
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+XML_Bool g_reparseDeferralEnabledDefault = XML_TRUE; // write ONLY in runtests.c
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+unsigned int g_parseAttempts = 0; // used for testing only
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+
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struct XML_ParserStruct {
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/* The first member must be userData so that the XML_GetUserData
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macro works. */
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@@ -491,6 +500,9 @@ struct XML_ParserStruct {
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const char *m_bufferLim;
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XML_Index m_parseEndByteIndex;
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const char *m_parseEndPtr;
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+ size_t m_partialTokenBytesBefore; /* used in heuristic to avoid O(n^2) */
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+ XML_Bool m_reparseDeferralEnabled;
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+ int m_lastBufferRequestSize;
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XML_Char *m_dataBuf;
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XML_Char *m_dataBufEnd;
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XML_StartElementHandler m_startElementHandler;
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@@ -647,6 +659,9 @@ struct XML_ParserStruct {
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#define bufferEnd (parser->m_bufferEnd)
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#define parseEndByteIndex (parser->m_parseEndByteIndex)
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#define parseEndPtr (parser->m_parseEndPtr)
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+#define partialTokenBytesBefore (parser->m_partialTokenBytesBefore)
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+#define reparseDeferralEnabled (parser->m_reparseDeferralEnabled)
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+#define lastBufferRequestSize (parser->m_lastBufferRequestSize)
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#define bufferLim (parser->m_bufferLim)
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#define dataBuf (parser->m_dataBuf)
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#define dataBufEnd (parser->m_dataBufEnd)
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@@ -887,6 +902,47 @@ get_hash_secret_salt(XML_Parser parser)
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return parser->m_hash_secret_salt;
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}
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+static enum XML_Error
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+callProcessor(XML_Parser parser, const char *start, const char *end,
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+ const char **endPtr) {
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+ const size_t have_now = EXPAT_SAFE_PTR_DIFF(end, start);
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+
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+ if (parser->m_reparseDeferralEnabled
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+ && ! parser->m_parsingStatus.finalBuffer) {
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+ // Heuristic: don't try to parse a partial token again until the amount of
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+ // available data has increased significantly.
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+ const size_t had_before = parser->m_partialTokenBytesBefore;
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+ // ...but *do* try anyway if we're close to causing a reallocation.
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+ size_t available_buffer
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+ = EXPAT_SAFE_PTR_DIFF(parser->m_bufferPtr, parser->m_buffer);
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+#if XML_CONTEXT_BYTES > 0
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+ available_buffer -= EXPAT_MIN(available_buffer, XML_CONTEXT_BYTES);
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+#endif
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+ available_buffer
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+ += EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_bufferEnd);
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+ // m_lastBufferRequestSize is never assigned a value < 0, so the cast is ok
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+ const bool enough
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+ = (have_now >= 2 * had_before)
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+ || ((size_t)parser->m_lastBufferRequestSize > available_buffer);
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+
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+ if (! enough) {
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+ *endPtr = start; // callers may expect this to be set
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+ return XML_ERROR_NONE;
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+ }
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+ }
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+ g_parseAttempts += 1;
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+ const enum XML_Error ret = parser->m_processor(parser, start, end, endPtr);
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+ if (ret == XML_ERROR_NONE) {
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+ // if we consumed nothing, remember what we had on this parse attempt.
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+ if (*endPtr == start) {
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+ parser->m_partialTokenBytesBefore = have_now;
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+ } else {
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+ parser->m_partialTokenBytesBefore = 0;
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+ }
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+ }
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+ return ret;
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+}
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+
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static XML_Bool /* only valid for root parser */
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startParsing(XML_Parser parser)
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{
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@@ -1075,6 +1131,9 @@ parserInit(XML_Parser parser, const XML_
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bufferEnd = buffer;
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parseEndByteIndex = 0;
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parseEndPtr = NULL;
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+ partialTokenBytesBefore = 0;
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+ reparseDeferralEnabled = g_reparseDeferralEnabledDefault;
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+ lastBufferRequestSize = 0;
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declElementType = NULL;
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declAttributeId = NULL;
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declEntity = NULL;
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@@ -1232,6 +1291,7 @@ XML_ExternalEntityParserCreate(XML_Parse
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to worry which hash secrets each table has.
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*/
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unsigned long oldhash_secret_salt;
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+ XML_Bool oldReparseDeferralEnabled;
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/* Validate the oldParser parameter before we pull everything out of it */
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if (oldParser == NULL)
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@@ -1276,6 +1336,7 @@ XML_ExternalEntityParserCreate(XML_Parse
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to worry which hash secrets each table has.
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*/
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oldhash_secret_salt = hash_secret_salt;
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+ oldReparseDeferralEnabled = reparseDeferralEnabled;
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#ifdef XML_DTD
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if (!context)
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@@ -1330,6 +1391,7 @@ XML_ExternalEntityParserCreate(XML_Parse
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defaultExpandInternalEntities = oldDefaultExpandInternalEntities;
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ns_triplets = oldns_triplets;
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hash_secret_salt = oldhash_secret_salt;
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+ reparseDeferralEnabled = oldReparseDeferralEnabled;
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parentParser = oldParser;
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#ifdef XML_DTD
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paramEntityParsing = oldParamEntityParsing;
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@@ -1850,39 +1912,8 @@ XML_Parse(XML_Parser parser, const char
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ps_parsing = XML_PARSING;
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}
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- if (len == 0) {
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- ps_finalBuffer = (XML_Bool)isFinal;
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- if (!isFinal)
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- return XML_STATUS_OK;
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- positionPtr = bufferPtr;
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- parseEndPtr = bufferEnd;
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-
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- /* If data are left over from last buffer, and we now know that these
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- data are the final chunk of input, then we have to check them again
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- to detect errors based on that fact.
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- */
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- errorCode = processor(parser, bufferPtr, parseEndPtr, &bufferPtr);
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-
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- if (errorCode == XML_ERROR_NONE) {
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- switch (ps_parsing) {
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- case XML_SUSPENDED:
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- XmlUpdatePosition(encoding, positionPtr, bufferPtr, &position);
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- positionPtr = bufferPtr;
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- return XML_STATUS_SUSPENDED;
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- case XML_INITIALIZED:
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- case XML_PARSING:
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- ps_parsing = XML_FINISHED;
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- /* fall through */
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- default:
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- return XML_STATUS_OK;
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- }
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- }
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- eventEndPtr = eventPtr;
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- processor = errorProcessor;
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- return XML_STATUS_ERROR;
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- }
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#ifndef XML_CONTEXT_BYTES
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- else if (bufferPtr == bufferEnd) {
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+ if (bufferPtr == bufferEnd) {
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const char *end;
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int nLeftOver;
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enum XML_Status result;
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@@ -1899,11 +1930,14 @@ XML_Parse(XML_Parser parser, const char
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processor = errorProcessor;
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return XML_STATUS_ERROR;
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}
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+ // though this isn't a buffer request, we assume that `len` is the app's
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+ // preferred buffer fill size, and therefore save it here.
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+ lastBufferRequestSize = len;
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parseEndByteIndex += len;
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positionPtr = s;
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ps_finalBuffer = (XML_Bool)isFinal;
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- errorCode = processor(parser, s, parseEndPtr = s + len, &end);
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+ errorCode = callProcessor(parser, s, parseEndPtr = s + len, &end);
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if (errorCode != XML_ERROR_NONE) {
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eventEndPtr = eventPtr;
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@@ -1930,6 +1964,8 @@ XML_Parse(XML_Parser parser, const char
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XmlUpdatePosition(encoding, positionPtr, end, &position);
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nLeftOver = s + len - end;
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if (nLeftOver) {
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+#if 0
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+// erAck: replace with XML_GetBuffer() below.
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if (buffer == NULL || nLeftOver > bufferLim - buffer) {
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/* avoid _signed_ integer overflow */
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char *temp = NULL;
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@@ -1939,6 +1975,28 @@ XML_Parse(XML_Parser parser, const char
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? (char *)MALLOC(bytesToAllocate)
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: (char *)REALLOC(buffer, bytesToAllocate));
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}
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+#endif
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+#if 1
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+// erAck: the original patch context had a call to XML_GetBuffer() instead:
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+ // Back up and restore the parsing status to avoid XML_ERROR_SUSPENDED
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+ // (and XML_ERROR_FINISHED) from XML_GetBuffer.
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+ const enum XML_Parsing originalStatus = ps_parsing;
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+ ps_parsing = XML_PARSING;
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+ void *const temp = XML_GetBuffer(parser, nLeftOver);
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+ ps_parsing = originalStatus;
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+#endif
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+ // GetBuffer may have overwritten this, but we want to remember what the
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+ // app requested, not how many bytes were left over after parsing.
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+ lastBufferRequestSize = len;
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+#if 1
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+ if (temp == NULL) {
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+ // NOTE: parser->m_errorCode has already been set by XML_GetBuffer().
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+ eventPtr = eventEndPtr = NULL;
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+ processor = errorProcessor;
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+ return XML_STATUS_ERROR;
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+ }
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+#endif
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+#if 0
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if (temp == NULL) {
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errorCode = XML_ERROR_NO_MEMORY;
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eventPtr = eventEndPtr = NULL;
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@@ -1948,6 +2006,7 @@ XML_Parse(XML_Parser parser, const char
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buffer = temp;
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bufferLim = buffer + bytesToAllocate;
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}
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+#endif
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memcpy(buffer, end, nLeftOver);
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}
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bufferPtr = buffer;
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@@ -1959,15 +2018,14 @@ XML_Parse(XML_Parser parser, const char
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return result;
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}
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#endif /* not defined XML_CONTEXT_BYTES */
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- else {
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- void *buff = XML_GetBuffer(parser, len);
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- if (buff == NULL)
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- return XML_STATUS_ERROR;
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- else {
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- memcpy(buff, s, len);
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- return XML_ParseBuffer(parser, len, isFinal);
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- }
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+ void *buff = XML_GetBuffer(parser, len);
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+ if (buff == NULL)
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+ return XML_STATUS_ERROR;
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+ if (len > 0) {
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+ assert(s != NULL); // make sure s==NULL && len!=0 was rejected above
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+ memcpy(buff, s, len);
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}
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+ return XML_ParseBuffer(parser, len, isFinal);
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}
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enum XML_Status XMLCALL
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@@ -2001,7 +2059,7 @@ XML_ParseBuffer(XML_Parser parser, int l
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parseEndByteIndex += len;
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ps_finalBuffer = (XML_Bool)isFinal;
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- errorCode = processor(parser, start, parseEndPtr, &bufferPtr);
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+ errorCode = callProcessor(parser, start, parseEndPtr, &bufferPtr);
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if (errorCode != XML_ERROR_NONE) {
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eventEndPtr = eventPtr;
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@@ -2047,7 +2105,11 @@ XML_GetBuffer(XML_Parser parser, int len
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default: ;
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}
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- if (len > bufferLim - bufferEnd) {
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+ // whether or not the request succeeds, `len` seems to be the app's preferred
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+ // buffer fill size; remember it.
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+ lastBufferRequestSize = len;
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+ if (len > EXPAT_SAFE_PTR_DIFF(bufferLim, bufferEnd)
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+ || buffer == NULL) {
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#ifdef XML_CONTEXT_BYTES
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int keep;
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#endif /* defined XML_CONTEXT_BYTES */
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@@ -2063,7 +2125,9 @@ XML_GetBuffer(XML_Parser parser, int len
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keep = XML_CONTEXT_BYTES;
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neededSize += keep;
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#endif /* defined XML_CONTEXT_BYTES */
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- if (neededSize <= bufferLim - buffer) {
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+ if (buffer && bufferPtr
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+ && neededSize
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+ <= EXPAT_SAFE_PTR_DIFF(bufferLim, buffer)) {
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#ifdef XML_CONTEXT_BYTES
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if (keep < bufferPtr - buffer) {
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int offset = (int)(bufferPtr - buffer) - keep;
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@@ -2072,8 +2136,11 @@ XML_GetBuffer(XML_Parser parser, int len
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bufferPtr -= offset;
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}
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#else
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- memmove(buffer, bufferPtr, bufferEnd - bufferPtr);
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- bufferEnd = buffer + (bufferEnd - bufferPtr);
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+ memmove(buffer, bufferPtr,
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+ EXPAT_SAFE_PTR_DIFF(bufferEnd, bufferPtr));
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+ bufferEnd
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+ = buffer
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+ + EXPAT_SAFE_PTR_DIFF(bufferEnd, bufferPtr);
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bufferPtr = buffer;
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#endif /* not defined XML_CONTEXT_BYTES */
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}
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@@ -2171,7 +2238,7 @@ XML_ResumeParser(XML_Parser parser)
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}
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ps_parsing = XML_PARSING;
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- errorCode = processor(parser, bufferPtr, parseEndPtr, &bufferPtr);
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+ errorCode = callProcessor(parser, bufferPtr, parseEndPtr, &bufferPtr);
|
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|
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if (errorCode != XML_ERROR_NONE) {
|
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eventEndPtr = eventPtr;
|
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@@ -2481,6 +2548,15 @@ MOZ_XML_ProcessingEntityValue(XML_Parser
|
||||
}
|
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/* END MOZILLA CHANGE */
|
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+XML_Bool XMLCALL
|
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+XML_SetReparseDeferralEnabled(XML_Parser parser, XML_Bool enabled) {
|
||||
+ if (parser != NULL && (enabled == XML_TRUE || enabled == XML_FALSE)) {
|
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+ parser->m_reparseDeferralEnabled = enabled;
|
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+ return XML_TRUE;
|
||||
+ }
|
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+ return XML_FALSE;
|
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+}
|
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+
|
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/* Initially tag->rawName always points into the parse buffer;
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for those TAG instances opened while the current parse buffer was
|
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processed, and not yet closed, we need to store tag->rawName in a more
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Loading…
Reference in new issue