Supporting more gitweb diff possibities

[mkoegler@auto.tuwien.ac.at (Martin Koegler)]

I have done a first series of 6 patches, which improves blobdiff and
adds treediff.

[PATCH] gitweb: show no difference message

This patch shows an "no difference" message instead of nothing for
equal objects.

[PATCH] gitweb: Support comparing blobs with different names

This patch adds support for comparing objects with different file
names using hb/hbp.

[PATCH] gitweb: link base commit (hpb) to blobdiff output

Add link the parent commit, as there is currently no such link.

[PATCH] gitweb: support filename prefix in git_patchset_body
[PATCH] gitweb: support filename prefix in git_difftree_body
[PATCH] gitweb: Add treediff

These 3 patches add the treediff method. Its a complete reworked
verion. As git-diff-tree outputs relativ patches (discards part of the
compared tree objects), the first two patches are necessary to produce
correct links in the treediff output.

I do not see many possibilties for code sharing with git_commitdiff:
The only large portion of common code is calling git-diff-tree. I
don't think that this would justify the more complex code.

To test these patches, I still use a JavaScript implementation (see
below). I'm working on the server side implementation.

The next patch, I'm currently working on, will introduce a wrapper for all
calls to
$cgi->a({-href => href([Parameter])}, [Title]) 

mfg Martin Kögler

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 71d0933..db58319 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -1837,6 +1837,7 @@ sub git_footer_html {
 		close $fd;
 	}
 
+	print '<script type="text/javascript" src="gitweb.js"></script>';
 	print "</body>\n" .
 	      "</html>";
 }


gitweb.js:
----------
function getCookie(name)
{
  var name=name+"=";
  var c=document.cookie;
  var p=c.indexOf(name);
  if(p==-1)
    return null;
  c=c.substr(p+name.length,c.length);
  p=c.indexOf(";");
  if(p==-1)
    return c;
  else
    return c.substr(0, p);
}

function insertAfter(elem, node)
{
  if(node.nextSibling)
    node.parentNode.insertBefore(elem, node.nextSibling);
  else
    node.parentNode.appendChild(elem);
}

function createLink(href, linktext)
{
  var l=document.createElement("a");
  l.appendChild(document.createTextNode(linktext));
  l.href=href;
  return l;
}

function createLinkGroup(href1, basetxt, href2, difftxt)
{
  var l=document.createElement("span");
  l.appendChild(document.createTextNode(" ("));
  l.appendChild(createLink(href1, basetxt));
  l.appendChild(document.createTextNode(" | "));
  l.appendChild(createLink(href2, difftxt));
  l.appendChild(document.createTextNode(") "));
  return l;
}

function GitRef()
{
    this.t=null;
    this.h=null;
    this.hb=null;
    this.f=null;
    this.ToRef=ToRef;
}

function ToRef()
{
  var parts=new Array();
  if(this.f)
    parts.push("f="+this.f);
  if(this.h)
    parts.push("h="+this.h);
  if(this.hb)
    parts.push("hb="+this.hb);
  if(this.t)
    parts.push("t="+this.t);
  return parts.join("@");
}

function splitGitRef(ref)
{
  var parts=ref.split("@");
  var res=new GitRef();
  var i;
  for(i=0;i<parts.length;i++)
  {
      var p=parts[i].split("=");
      res[p[0]]=p[1];
  }
  return res;
}

function GitURL(base)
{
  this.base=base;
  this.p=null;
  this.a=null;
  this.f=null;
  this.fp=null;
  this.h=null;
  this.hp=null;
  this.hb=null;
  this.hpb=null;
  this.pg=null;
  this.o=null;
  this.s=null;
  this.st=null;
  this.ToURL=ToURL;
  this.ToRef=UrlToRef;
  this.ToDUrl=ToDUrl;
}

function ToURL()
{
  var parts=new Array();
  if(this.p)
    parts.push("p="+this.p);
  if(this.a)
    parts.push("a="+this.a);
  if(this.f)
    parts.push("f="+this.f);
  if(this.fp)
    parts.push("fp="+this.fp);
  if(this.h)
    parts.push("h="+this.h);
  if(this.hp)
    parts.push("hp="+this.hp);
  if(this.hb)
    parts.push("hb="+this.hb);
  if(this.hpb)
    parts.push("hpb="+this.hpb);
  if(this.o)
    parts.push("o="+this.o);
  if(this.s)
    parts.push("s="+this.s);
  if(this.st)
    parts.push("st="+this.st);
  return this.base+"?"+parts.join(";");
}

function UrlToRef(type)
{
    var res=new GitRef;
    res.f=this.f;
    res.h=this.h;
    res.hb=this.hb;
    res.t=type;
    return res.ToRef();
}

function ToDUrl(type)
{
    var res=new GitURL(this.base);
    res.f=this.f;
    res.h=this.h;
    res.hb=this.hb;
    res.p=this.p;
    res.a=type;
    return res.ToURL();
}

function splitGitURL(url)
{
  var Urls=url.split("?");
  var res=new GitURL(Urls[0]);
  if(Urls.length>1)
    {
      var parts=Urls[1].split(";");
      var i;
      for(i=0;i<parts.length;i++)
	{
	  var p=parts[i].split("=");
	  res[p[0]]=p[1];
	}
    }
  return res;
}

function GitAddLinks()
{
  var links=document.getElementsByTagName("a");
  var i;
  for(i=0;i<links.length;i++)
    {
      var link=links[i];
      if(link.innerHTML=='commit'||link.innerHTML=='tag')
	{
	  var url=splitGitURL(link.href);
	  if(!url.h)
	    continue;
	  var l=createLinkGroup("javascript:base('"+url.ToRef('commit')+"')","base",
				"javascript:diff('"+url.ToDUrl('commit')+"')","diff");
	  insertAfter(l, link);
	}
      if(link.innerHTML=='blob')
	{
	  var url=splitGitURL(link.href);
	  if(!url.h&&!(url.hb&&url.f))
	    continue;
	  var l=createLinkGroup("javascript:base('"+url.ToRef('blob')+"')","base",
				"javascript:diff('"+url.ToDUrl('blob')+"')","diff");
	  insertAfter(l, link);
	}
      if(link.innerHTML=='tree')
	{
	  var url=splitGitURL(link.href);
	  if(!url.h&&!(url.hb&&url.f))
	    continue;
	  var l=createLinkGroup("javascript:base('"+url.ToRef('tree')+"')","base",
				"javascript:diff('"+url.ToDUrl('tree')+"')","diff");
	  insertAfter(l, link);
	}
    }
}

function base(ref)
{
  document.cookie="basename="+ref;
}

function diff(url)
{
  var c=getCookie("basename");
  if (!c)
  {
      alert("no diff base selected");
      return;
  }
  c=splitGitRef(c);
  url=splitGitURL(url);
  
  if(c.t=='commit'&&url.a=='commit')
  {
      url.a='commitdiff';
      if(!c.h||!url.h)
      {
	  alert("commit diff not possible");
	  return;
      }
      url.hb=null;
      url.f=null;
      url.hp=c.h;
      document.location.href=url.ToURL();
      return;
  }
  if(c.t=='blob'&&url.a=='blob')
  {
      url.a='blobdiff';
      url.h=c.h;
      url.hpb=c.hb;
      url.fp=c.f;
      document.location.href=url.ToURL();
      return;
  }
  if(c.t=='tree'&&url.a=='tree')
  {
      url.a='treediff';
      url.hpb=c.hb;
      url.hp=c.h;
      url.fp=c.f;
      document.location.href=url.ToURL();
      return;
  } 
  if(c.t=='commit'&&url.a=='tree')
  {
      url.a='treediff';
      url.hpb=c.h;
      url.hp=null;
      url.fp=null;
      document.location.href=url.ToURL();
      return;
  } 
  if(c.t=='tree'&&url.a=='commit')
  {
      url.a='treediff';
      url.hpb=c.hb;
      url.hp=c.h;
      url.fp=c.f;
      url.hb=url.h;
      url.h=null;
      document.location.href=url.ToURL();
      return;
  } 
  alert("diff not possible");
}

GitAddLinks();