pkg/search: add "ref:" predicate support

The "ref:prefix" search predicate is simply the equivalent of the

Constraint {
	BlobRefPrefix: prefix,
}

search constraint.

The "ref:prefix" search expression was already supported by the search
box of the web UI, but as opposed to (all, I think) other search
expressions, it was not supported server-side. Which means, it had to be
converted to a search Constraint as the above, before being sent in the
query.

This change therefore fixes this inconsistency. In addition, but
relatedly, since the map aspect relies on expressing the zoom-level as a
locrect expression, it is much simpler if the search query it uses only
has to be constructed from search expressions, and without search
constraints. So if we want to be able to support marking a single node
search with the map aspect, while dealing only with search expressions,
this change is necessary.

Fixes #939

Change-Id: Ia58f410198ecd1f7e0981321da370d687df3a120

pkg/search/predicate.go

@@ -110,6 +110,7 @@ func init() {
 	registerKeyword(newFormat())
 	registerKeyword(newTag())
 	registerKeyword(newTitle())
+	registerKeyword(newRef())
 
 	// Image predicates
 	registerKeyword(newIsImage())
@@ -423,6 +424,24 @@ func (t title) Predicate(ctx context.Context, args []string) (*Constraint, error
 	return c, nil
 }
 
+type ref struct {
+	matchPrefix
+}
+
+func newRef() keyword {
+	return ref{newMatchPrefix("ref")}
+}
+
+func (r ref) Description() string {
+	return "match nodes whose blobRef starts with the given substring"
+}
+
+func (r ref) Predicate(ctx context.Context, args []string) (*Constraint, error) {
+	return &Constraint{
+		BlobRefPrefix: args[0],
+	}, nil
+}
+
 // Image predicates
 
 type isImage struct {

pkg/search/predicate_test.go

@@ -307,6 +307,14 @@ var keywordTests = []keywordTestcase{
 		},
 	},
 
+	{
+		object: newRef(),
+		args:   []string{"sha1-foobar"},
+		want: &Constraint{
+			BlobRefPrefix: "sha1-foobar",
+		},
+	},
+
 	{
 		object: newWith(),
 		args:   []string{"fitz"},

server/camlistored/ui/index.js

@@ -514,7 +514,7 @@ cam.IndexPage = React.createClass({
 		this.targetSearchSession_ = null;
 		if (targetBlobref) {
 			var opt_sort = "blobref";
-			var query = this.queryAsBlob_(targetBlobref);
+			var query = this.queryFromSearchParam_("ref:"+targetBlobref);
 			var parentPermanode = newURL.getParameterValue('p');
 			if (parentPermanode) {
 				query = this.queryFromParentPermanode_(parentPermanode);
@@ -568,12 +568,6 @@ cam.IndexPage = React.createClass({
 		};
 	},
 
-	queryAsBlob_: function(blobRef) {
-		return {
-			blobRefPrefix: blobRef,
-		}
-	},
-
 	// Finds an existing cached SearchSession that meets criteria, or creates a new one.
 	//
 	// If opt_query is present, the returned query must be exactly equivalent.
@@ -956,6 +950,8 @@ cam.IndexPage = React.createClass({
 	getDetailURL_: function(blobref, opt_fragment) {
 		var query = this.state.currentURL.getParameterValue('q');
 		var targetBlobref = this.getTargetBlobref_();
+		// TODO(mpl): now that "ref:refprefix" searches are fully supported, maybe we
+		// could replace the mix of path+query URLs, with just query based URLs?
 		return url = this.baseURL_.clone().setPath(this.baseURL_.getPath() + blobref).setFragment(opt_fragment || '');
 	},
 

server/camlistored/ui/map.js

@@ -188,7 +188,6 @@ cam.MapAspect = React.createClass({
 			return;
 		}
 		var q = ss.getQueryExprOrRef();
-		// TODO(mpl): support "ref:sha1-foobar" predicate. Needs server-side first.
 		if (q == '') {
 			q = 'has:location';
 		}

server/camlistored/ui/search_session.js

@@ -88,9 +88,7 @@ cam.SearchSession.prototype.getQueryExprOrRef = function() {
 	if (!q.blobRefPrefix) {
 		return '';
 	}
-	// TODO(mpl): when server side supports "ref:" predicate, then:
-	// return 'ref:'+q.blobRefPrefix;
-	return '';
+	return 'ref:'+q.blobRefPrefix;
 };
 
 cam.SearchSession.prototype.isEmptyQuery = function() {