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

1 files changed, 25 insertions, 0 deletions

diff --git a/xzlib.c b/xzlib.c
index 928bd17c..150e8033 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)
 {