[libxml2] Fix a regression in xmlGetDocCompressMode()

[Daniel Veillard <veillard src gnome org>]

commit 63588f476f2dc89d4c6ef70a474d7230fbf4d45e
Author: Daniel Veillard <veillard redhat com>
Date:   Fri May 10 14:01:46 2013 +0800

    Fix a regression in xmlGetDocCompressMode()
    
    The switch to xzlib had for consequence that the compression
    level of the input was not gathered anymore in ctxt->input->buf,
    then the parser compression flags was left to -1 and propagated
    to the resulting document.
    Fix the I/O layer to get compression detection in xzlib,
    then carry it in the input buffer and the resulting document
    
      This should fix
        https://lsbbugs.linuxfoundation.org/show_bug.cgi?id=3456

 parser.c |    4 ++++
 xmlIO.c  |   17 +++++++++++++++++
 xzlib.c  |   25 +++++++++++++++++++++++++
 xzlib.h  |    1 +
 4 files changed, 47 insertions(+), 0 deletions(-)
---
diff --git a/parser.c b/parser.c
index 1d478c3..4a442bb 100644
--- a/parser.c
+++ b/parser.c
@@ -10681,6 +10681,10 @@ xmlParseDocument(xmlParserCtxtPtr ctxt) {
         ctxt->sax->startDocument(ctxt->userData);
     if (ctxt->instate == XML_PARSER_EOF)
        return(-1);
+    if ((ctxt->myDoc != NULL) && (ctxt->input != NULL) &&
+        (ctxt->input->buf != NULL) && (ctxt->input->buf->compressed >= 0)) {
+       ctxt->myDoc->compression = ctxt->input->buf->compressed;
+    }
 
     /*
      * The Misc part of the Prolog
diff --git a/xmlIO.c b/xmlIO.c
index 847cb7e..fc4e111 100644
--- a/xmlIO.c
+++ b/xmlIO.c
@@ -2669,6 +2669,12 @@ __xmlParserInputBufferCreateFilename(const char *URI, xmlCharEncoding enc) {
 #endif
        }
 #endif
+#ifdef HAVE_LZMA_H
+       if ((xmlInputCallbackTable[i].opencallback == xmlXzfileOpen) &&
+               (strcmp(URI, "-") != 0)) {
+            ret->compressed = __libxml2_xzcompressed(context);
+       }
+#endif
     }
     else
       xmlInputCallbackTable[i].closecallback (context);
@@ -3325,6 +3331,17 @@ xmlParserInputBufferGrow(xmlParserInputBufferPtr in, int len) {
     if (res < 0) {
        return(-1);
     }
+
+    /*
+     * try to establish compressed status of input if not done already
+     */
+    if (in->compressed == -1) {
+#ifdef HAVE_LZMA_H
+       if (in->readcallback == xmlXzfileRead)
+            in->compressed = __libxml2_xzcompressed(in->context);
+#endif
+    }
+
     len = res;
     if (in->encoder != NULL) {
         unsigned int use;
diff --git a/xzlib.c b/xzlib.c
index 928bd17..150e803 100644
--- a/xzlib.c
+++ b/xzlib.c
@@ -182,12 +182,37 @@ xz_open(const char *path, int fd, const char *mode ATTRIBUTE_UNUSED)
     return (xzFile) state;
 }
 
+static int
+xz_compressed(xzFile f) {
+    xz_statep state;
+
+    if (f == NULL)
+        return(-1);
+    state = (xz_statep) f;
+    if (state->init <= 0)
+        return(-1);
+
+    switch (state->how) {
+        case COPY:
+           return(0);
+       case GZIP:
+       case LZMA:
+           return(1);
+    }
+    return(-1);
+}
+
 xzFile
 __libxml2_xzopen(const char *path, const char *mode)
 {
     return xz_open(path, -1, mode);
 }
 
+int
+__libxml2_xzcompressed(xzFile f) {
+    return xz_compressed(f);
+}
+
 xzFile
 __libxml2_xzdopen(int fd, const char *mode)
 {
diff --git a/xzlib.h b/xzlib.h
index 43c75e1..29ba55e 100644
--- a/xzlib.h
+++ b/xzlib.h
@@ -15,4 +15,5 @@ xzFile __libxml2_xzopen(const char *path, const char *mode);
 xzFile __libxml2_xzdopen(int fd, const char *mode);
 int __libxml2_xzread(xzFile file, void *buf, unsigned len);
 int __libxml2_xzclose(xzFile file);
+int __libxml2_xzcompressed(xzFile f);
 #endif /* LIBXML2_XZLIB_H */