From 0745a0943d4050e864f00f9fc83a075d32d51d60 Mon Sep 17 00:00:00 2001
From: "Sascha L. Teichmann" <sascha.teichmann@intevation.de>
Date: Thu, 26 Jan 2023 21:54:46 +0100
Subject: [PATCH] Separate compiling and evaluation of dynamic categories.

---
 cmd/csaf_aggregator/mirror.go | 22 +++++++++++++++-------
 cmd/csaf_provider/actions.go  | 16 +++++++++++-----
 util/json.go                  | 33 ++++++++++++++-------------------
 3 files changed, 40 insertions(+), 31 deletions(-)

diff --git a/cmd/csaf_aggregator/mirror.go b/cmd/csaf_aggregator/mirror.go
index 3ea4837..fd37b3e 100644
--- a/cmd/csaf_aggregator/mirror.go
+++ b/cmd/csaf_aggregator/mirror.go
@@ -453,22 +453,30 @@ func (w *worker) extractCategories(label string, advisory any) error {
 
 	const exprPrefix = "expr:"
 
+	var dynamic []string
+	matcher := util.StringTreeMatcher(&dynamic)
+
 	for _, cat := range categories {
 		if strings.HasPrefix(cat, exprPrefix) {
 			expr := cat[len(exprPrefix):]
-			var results []string
-			matcher := util.StringTreeMatcher(&results)
-			if err := w.expr.Extract(expr, matcher, true, advisory); err != nil {
-				return err
-			}
-			for _, result := range results {
-				cats[result] = true
+			// Compile first to check that the expression is okay.
+			if _, err := w.expr.Compile(expr); err != nil {
+				fmt.Printf("Compiling category expression %q failed: %v\n",
+					expr, err)
+				continue
 			}
+			// Ignore errors here as they result from not matching.
+			w.expr.Extract(expr, matcher, true, advisory)
 		} else { // Normal
 			cats[cat] = true
 		}
 	}
 
+	// Add dynamic categories.
+	for _, cat := range dynamic {
+		cats[cat] = true
+	}
+
 	return nil
 }
 
diff --git a/cmd/csaf_provider/actions.go b/cmd/csaf_provider/actions.go
index 67b36a5..0fa4e5b 100644
--- a/cmd/csaf_provider/actions.go
+++ b/cmd/csaf_provider/actions.go
@@ -194,11 +194,17 @@ func (c *controller) upload(r *http.Request) (any, error) {
 	// Check if we have to search for dynamic categories.
 	var dynamicCategories []string
 	if catExprs := c.cfg.DynamicCategories(); len(catExprs) > 0 {
-		var err error
-		if dynamicCategories, err = pe.StringsFromTree(
-			catExprs, true, content); err != nil {
-			// XXX: Should we die here?
-			log.Printf("eval of dynamic category expressions failed: %v\n", err)
+		matcher := util.StringTreeMatcher(&dynamicCategories)
+
+		for _, expr := range catExprs {
+			// Compile first to check that the expression is okay.
+			if _, err := pe.Compile(expr); err != nil {
+				log.Printf("Compiling category expression %q failed: %v\n",
+					expr, err)
+				continue
+			}
+			// Ignore errors here as they result from not matching.
+			pe.Extract(expr, matcher, true, content)
 		}
 	}
 
diff --git a/util/json.go b/util/json.go
index 985c7e1..be9f330 100644
--- a/util/json.go
+++ b/util/json.go
@@ -42,6 +42,20 @@ func NewPathEval() *PathEval {
 	}
 }
 
+// Compile compiles an expression and stores it in the
+// internal cache on success.
+func (pe *PathEval) Compile(expr string) (gval.Evaluable, error) {
+	if eval := pe.exprs[expr]; eval != nil {
+		return eval, nil
+	}
+	eval, err := pe.builder.NewEvaluable(expr)
+	if err != nil {
+		return nil, err
+	}
+	pe.exprs[expr] = eval
+	return eval, nil
+}
+
 // Eval evalutes expression expr on document doc.
 // Returns the result of the expression.
 func (pe *PathEval) Eval(expr string, doc any) (any, error) {
@@ -178,25 +192,6 @@ func (pe *PathEval) Match(matcher []PathEvalMatcher, doc any) error {
 	return nil
 }
 
-// StringsFromTree returns strings from the given exprs.
-//  1. If an expression results in a string this string is used.
-//  2. if an expression results in an array the elements
-//     of this array are recursively treated with 1. and 2.
-func (pe *PathEval) StringsFromTree(
-	exprs []string,
-	optional bool,
-	doc any,
-) ([]string, error) {
-	results := make([]string, 0, len(exprs))
-	matcher := StringTreeMatcher(&results)
-	for _, expr := range exprs {
-		if err := pe.Extract(expr, matcher, optional, doc); err != nil {
-			return nil, err
-		}
-	}
-	return results, nil
-}
-
 // Strings searches the given document for the given set of expressions
 // and returns the corresponding strings. The optional flag indicates
 // if the expression evaluation have to succseed or not.