Add an opaque datatype for managing a set of XML namespace declarations.

Part of an upcoming propdb API improvement.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91004 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/modules/dav/main/mod_dav.h b/modules/dav/main/mod_dav.h
index de779730ca0b15a887d425901ab92754b3f745cd..fd707d0e1028f01ad1c51d6fb8818f33ca86d6b7 100644 (file)
--- a/modules/dav/main/mod_dav.h
+++ b/modules/dav/main/mod_dav.h
@@ -529,6 +529,49 @@ ap_xml_elem *dav_find_child(const ap_xml_elem *elem, const char *tagname);
 const char *dav_xml_get_cdata(const ap_xml_elem *elem, apr_pool_t *pool,
                               int strip_white);
 
+/*
+** XML namespace handling
+**
+** This structure tracks namespace declarations (xmlns:prefix="URI").
+** It maintains a many-to-one relationship of URIs-to-prefixes. In other
+** words, a URI may be defined by multiple prefixes, but any specific
+** prefix will specify only one URI.
+**
+** Prefixes using the "g###" pattern can be generated automatically if
+** the caller does not have specific prefix requirements.
+*/
+typedef struct {
+    apr_pool_t *pool;
+    apr_hash_t *uri_prefix;     /* map URIs to an available prefix */
+    apr_hash_t *prefix_uri;     /* map all prefixes to their URIs */
+    int count;                  /* counter for "g###" prefixes */
+} dav_xmlns_info;
+
+/* create an empty dav_xmlns_info structure */
+DAV_DECLARE(dav_xmlns_info *) dav_xmlns_create(apr_pool_t *pool);
+
+/* add a specific prefix/URI pair. the prefix/uri should have a lifetime
+   at least that of xmlns->pool */
+DAV_DECLARE(void) dav_xmlns_add(dav_xmlns_info *xi,
+                                const char *prefix, const char *uri);
+
+/* add a URI (if not present); any prefix is acceptable and is returned.
+   the uri should have a lifetime at least that xmlns->pool */
+DAV_DECLARE(const char *) dav_xmlns_add_uri(dav_xmlns_info *xi,
+                                            const char *uri);
+
+/* return the URI for a specified prefix (or NULL if the prefix is unknown) */
+DAV_DECLARE(const char *) dav_xmlns_get_uri(dav_xmlns_info *xi,
+                                            const char *prefix);
+
+/* return an available prefix for a specified URI (or NULL if the URI
+   is unknown) */
+DAV_DECLARE(const char *) dav_xmlns_get_prefix(dav_xmlns_info *xi,
+                                               const char *uri);
+
+/* generate xmlns declarations (appending into the given text) */
+DAV_DECLARE(void) dav_xmlns_generate(dav_xmlns_info *xi,
+                                     apr_text_header *phdr);
 
 /* --------------------------------------------------------------------
 **

diff --git a/modules/dav/main/util.c b/modules/dav/main/util.c
index 01d345f253a522d6a625c0d789779ec73e0252a8..1fda3b2699f7f228d69f399252564848c605b08e 100644 (file)
--- a/modules/dav/main/util.c
+++ b/modules/dav/main/util.c
@@ -400,6 +400,71 @@ const char *dav_xml_get_cdata(const ap_xml_elem *elem, apr_pool_t *pool,
     return cdata;
 }
 
+DAV_DECLARE(dav_xmlns_info *) dav_xmlns_create(apr_pool_t *pool)
+{
+    dav_xmlns_info *xi = apr_pcalloc(pool, sizeof(*xi));
+
+    xi->uri_prefix = apr_hash_make(pool);
+    xi->prefix_uri = apr_hash_make(pool);
+
+    return xi;
+}
+
+DAV_DECLARE(void) dav_xmlns_add(dav_xmlns_info *xi,
+                                const char *prefix, const char *uri)
+{
+    /* this "should" not overwrite a prefix mapping */
+    apr_hash_set(xi->prefix_uri, prefix, APR_HASH_KEY_STRING, uri);
+
+    /* note: this may overwrite an existing URI->prefix mapping, but it
+       doesn't matter -- any prefix is usuable to specify the URI. */
+    apr_hash_set(xi->uri_prefix, uri, APR_HASH_KEY_STRING, prefix);
+}
+
+DAV_DECLARE(const char *) dav_xmlns_add_uri(dav_xmlns_info *xi,
+                                            const char *uri)
+{
+    const char *prefix;
+
+    if ((prefix = apr_hash_get(xi->uri_prefix, uri,
+                               APR_HASH_KEY_STRING)) != NULL)
+        return prefix;
+
+    prefix = apr_psprintf(xi->pool, "g%d", xi->count++);
+    dav_xmlns_add(xi, prefix, uri);
+    return prefix;
+}
+
+DAV_DECLARE(const char *) dav_xmlns_get_uri(dav_xmlns_info *xi,
+                                            const char *prefix)
+{
+    return apr_hash_get(xi->prefix_uri, prefix, APR_HASH_KEY_STRING);
+}
+
+DAV_DECLARE(const char *) dav_xmlns_get_prefix(dav_xmlns_info *xi,
+                                               const char *uri)
+{
+    return apr_hash_get(xi->uri_prefix, uri, APR_HASH_KEY_STRING);
+}
+
+DAV_DECLARE(void) dav_xmlns_generate(dav_xmlns_info *xi,
+                                     apr_text_header *phdr)
+{
+    apr_hash_index_t *hi = apr_hash_first(xi->pool, xi->prefix_uri);
+
+    for (; hi != NULL; hi = apr_hash_next(hi)) {
+        const void *prefix;
+        void *uri;
+        const char *s;
+
+        apr_hash_this(hi, &prefix, NULL, &uri);
+
+        s = apr_psprintf(xi->pool, " xmlns:%s=\"%s\"",
+                         (const char *)prefix, (const char *)uri);
+        ap_text_append(xi->pool, phdr, s);
+    }
+}
+
 /* ---------------------------------------------------------------
 **
 ** Timeout header processing