From 0c556ae0cc369d43b0486c429a3ba03c4fd69410 Mon Sep 17 00:00:00 2001
From: Dmitry Ledentsov <dmlled@yahoo.com>
Date: Sun, 31 Dec 2023 19:03:11 +0100
Subject: [PATCH] prepare recursive script parsing

---
 common/nix_candidate_source.go | 40 +++++++++++++++-------------------
 common/script_parser.go        | 27 +++++++++++++++++++++++
 2 files changed, 44 insertions(+), 23 deletions(-)
 create mode 100644 common/script_parser.go

diff --git a/common/nix_candidate_source.go b/common/nix_candidate_source.go
index 48736fc..d9195ad 100644
--- a/common/nix_candidate_source.go
+++ b/common/nix_candidate_source.go
@@ -10,20 +10,21 @@ import (
 
 	g "github.com/zyedidia/generic"
 	"github.com/zyedidia/generic/hashset"
-	"mvdan.cc/sh/v3/syntax"
 )
 
 type NixCandidateSource struct {
-	fs      Filesystem
-	sources map[string]*PathSetIn
-	key     string
+	fs                          Filesystem
+	sources                     map[string]*PathSetIn
+	expandedPathsAlreadyCrawled map[string]bool
+	key                         string
 }
 
 func NewNixCandidateSource(fs Filesystem, key string) CandidateSource {
 	res := &NixCandidateSource{
-		fs:      fs,
-		sources: map[string]*PathSetIn{},
-		key:     key,
+		fs:                          fs,
+		sources:                     map[string]*PathSetIn{},
+		expandedPathsAlreadyCrawled: map[string]bool{},
+		key:                         key,
 	}
 	res.crawlKnownPaths()
 	res.crawlPathLists()
@@ -40,30 +41,23 @@ func (s *NixCandidateSource) WhereSet(somePath string) *PathSetIn {
 
 func (s *NixCandidateSource) crawlKnownPaths() {
 	ForEachKnownPath(func(originalSource, expandedSource string) {
-		// try getting the contents
-		input, err := readAllText(expandedSource)
-		if err != nil {
+		if s.expandedPathsAlreadyCrawled[expandedSource] {
 			return
 		}
+		// do not crawl this file again
+		s.expandedPathsAlreadyCrawled[expandedSource] = true
 
-		// parse
-		r := strings.NewReader(input)
-		f, err := syntax.NewParser().Parse(r, "")
+		// try getting the contents
+		input, err := readAllText(expandedSource)
 		if err != nil {
 			return
 		}
 
-		syntax.Walk(f, func(node syntax.Node) bool {
-			switch x := node.(type) {
-			case *syntax.Assign:
-				if s.key == x.Name.Value {
-					harvestedPaths := s.harvestPaths(input[x.Value.Pos().Offset():x.Value.End().Offset()])
-					for _, harvestedPath := range harvestedPaths {
-						s.tryUpdatePathMap(harvestedPath, originalSource, expandedSource)
-					}
-				}
+		ForEachVariableAssignment(s.key, input, func(value string) {
+			harvestedPaths := s.harvestPaths(value)
+			for _, harvestedPath := range harvestedPaths {
+				s.tryUpdatePathMap(harvestedPath, originalSource, expandedSource)
 			}
-			return true
 		})
 	})
 }
diff --git a/common/script_parser.go b/common/script_parser.go
new file mode 100644
index 0000000..36c16d6
--- /dev/null
+++ b/common/script_parser.go
@@ -0,0 +1,27 @@
+package common
+
+import (
+	"strings"
+
+	"mvdan.cc/sh/v3/syntax"
+)
+
+func ForEachVariableAssignment(key, input string, fn func(string)) {
+	// parse
+	r := strings.NewReader(input)
+	f, err := syntax.NewParser().Parse(r, "")
+	if err != nil {
+		return
+	}
+
+	syntax.Walk(f, func(node syntax.Node) bool {
+		switch x := node.(type) {
+		case *syntax.Assign:
+			if key == x.Name.Value {
+				value := input[x.Value.Pos().Offset():x.Value.End().Offset()]
+				fn(value)
+			}
+		}
+		return true
+	})
+}