FileAnalysis: decentralize unique file handle generator callbacks.

The framework now cycles through callbacks based on a table indexed
by analyzer tags, or the special case of service strings if a given
analyzer is overloaded for multiple protocols (FTP/IRC data).  This
lets each protocol script bundle implement the callback locally and
reduces the FAF's external dependencies.

scripts/base/protocols/http/__load__.bro

@@ -1,5 +1,6 @@
 @load ./main
 @load ./utils
+@load ./file-analysis
 @load ./file-ident
 @load ./file-hash
 @load ./file-extract

scripts/base/protocols/http/file-analysis.bro

@@ -0,0 +1,21 @@
+@load ./main
+@load ./utils
+@load base/utils/conn-ids
+@load base/frameworks/file-analysis/main
+
+module HTTP;
+
+function get_file_handle(c: connection, is_orig: bool): string
+	{
+	if ( ! c?$http ) return "";
+
+	if ( c$http$range_request )
+		return fmt("%s http(%s): %s: %s", c$start_time, is_orig,
+		           c$id$orig_h, build_url(c$http));
+	return fmt("%s http(%s, %s): %s", c$start_time, is_orig,
+	           c$http$trans_depth, id_string(c$id));
+	}
+
+redef FileAnalysis::handle_callbacks += {
+	[ANALYZER_HTTP] = get_file_handle,
+};