[PATCH 1/3] Add url_check() function.

[Stefano Sabatini]

---
 libavformat/avio.c |   16 ++++++++++++++++
 libavformat/avio.h |    9 +++++++++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/libavformat/avio.c b/libavformat/avio.c
index 4399878..ac23d59 100644
--- a/libavformat/avio.c
+++ b/libavformat/avio.c
@@ -285,6 +285,22 @@ int url_exist(const char *filename)
     return 1;
 }
 
+int url_check(const char *url, int flags)
+{
+    URLContext *h;
+    int ret = url_alloc(&h, url, flags);
+    if (ret)
+        return ret;
+
+    if (h->prot->url_check)
+        ret = h->prot->url_check(h, flags);
+    else
+        ret = (ret = url_connect(h)) < 0 ? ret : 1;
+
+    url_close(h);
+    return ret;
+}
+
 int64_t url_filesize(URLContext *h)
 {
     int64_t pos, size;
diff --git a/libavformat/avio.h b/libavformat/avio.h
index 1e97357..db5f081 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -166,6 +166,14 @@ int url_close(URLContext *h);
 int url_exist(const char *url);
 
 /**
+ * Return a positive value if the resource indicated by url can be
+ * accessed with the mode indicated by flags, 0 if the resource cannot
+ * be accessed in that way, a negative value corresponding to an
+ * AVERROR code in case of failure.
+ */
+int url_check(const char *url, int flags);
+
+/**
  * Return the filesize of the resource accessed by h, AVERROR(ENOSYS)
  * if the operation is not supported by h, or another negative value
  * corresponding to an AVERROR error code in case of failure.
@@ -259,6 +267,7 @@ typedef struct URLProtocol {
     int (*url_get_file_handle)(URLContext *h);
     int priv_data_size;
     const AVClass *priv_data_class;
+    int (*url_check)(URLContext *h, int flags);
 } URLProtocol;
 
 #if FF_API_REGISTER_PROTOCOL
-- 
1.7.1


--uAKRQypu60I7Lcqm--