Only enable pipelining if server is HTTP/1.1

Just enabling it for anyone breaks with HTTP/1.0 servers and
proxies sometimes.

Closes: #810796

methods/server.cc

@@ -150,9 +150,15 @@ bool ServerState::HeaderLine(string Line)
       else
       {
 	 if (Major == 1 && Minor == 0)
+	 {
 	    Persistent = false;
+	 }
 	 else
+	 {
 	    Persistent = true;
+	    if (PipelineAllowed)
+	       Pipeline = true;
+	 }
       }
 
       return true;
@@ -532,6 +538,7 @@ int ServerMethod::Loop()
 	    _error->Discard();
 	    Server->Close();
 	    Server->Pipeline = false;
+	    Server->PipelineAllowed = false;
 	    
 	    if (FailCounter >= 2)
 	    {
@@ -604,6 +611,7 @@ int ServerMethod::Loop()
 			   strprintf(out, _("Automatically disabled %s due to incorrect response from server/proxy. (man 5 apt.conf)"), "Acquire::http::PipelineDepth");
 			   std::cerr << "W: " << out << std::endl;
 			   Server->Pipeline = false;
+			   Server->PipelineAllowed = false;
 			   // we keep the PipelineDepth value so that the rest of the queue can be fixed up as well
 			}
 			Rename(Res.Filename, I->DestFile);

methods/server.h

@@ -51,6 +51,7 @@ struct ServerState
    enum {Chunked,Stream,Closes} Encoding;
    enum {Header, Data} State;
    bool Persistent;
+   bool PipelineAllowed;
    std::string Location;
 
    // This is a Persistent attribute of the server itself.
@@ -86,7 +87,7 @@ struct ServerState
    bool Comp(URI Other) const {return Other.Host == ServerName.Host && Other.Port == ServerName.Port;};
    virtual void Reset() {Major = 0; Minor = 0; Result = 0; Code[0] = '\0'; TotalFileSize = 0; JunkSize = 0;
 		 StartPos = 0; Encoding = Closes; time(&Date); HaveContent = false;
-		 State = Header; Persistent = false; Pipeline = true; MaximumSize = 0;};
+		 State = Header; Persistent = false; Pipeline = false; MaximumSize = 0; PipelineAllowed = true;};
    virtual bool WriteResponse(std::string const &Data) = 0;
 
    /** \brief Transfer the data from the socket */

test/integration/test-http-pipeline-messup

@@ -8,6 +8,7 @@ setupenvironment
 configarchitecture "i386"
 
 # try a little harder to create a size mismatch
+buildsimplenativepackage 'pkg0' 'all' '1.0' 'stable' "Depends: foo" '' '' '' '' 'none'
 buildsimplenativepackage 'pkga' 'all' '1.0' 'stable' "Depends: foo" '' '' '' '' 'none'
 buildsimplenativepackage 'pkgb' 'all' '1.0' 'stable' "Depends: foo" '' '' '' '' 'none'
 buildsimplenativepackage 'pkgc' 'all' '1.0' 'stable' "Depends: f$(for i in $(seq 0 1000); do printf 'o'; done)" '' '' '' '' 'none'
@@ -43,8 +44,8 @@ done
 echo 'Acquire::http::Pipeline-Depth 10;' > ../rootdir/etc/apt/apt.conf.d/99enable-pipeline
 
 # the output is a bit strange: it looks like it has downloaded pkga 4 times
-testwarning aptget download pkga pkgb pkgc pkgd
-for pkg in 'pkga' 'pkgb' 'pkgc' 'pkgd'; do
+testwarning aptget download pkg0 pkga pkgb pkgc pkgd
+for pkg in 'pkg0' 'pkga' 'pkgb' 'pkgc' 'pkgd'; do
 	testsuccess test -f ${pkg}_1.0_all.deb
 	testsuccess cmp ../incoming/${pkg}_1.0_all.deb ${pkg}_1.0_all.deb
 	rm -f ${pkg}_1.0_all.deb