Add GetPathString

The method is a thin wrapper around GetWalkPath and GetTagPath to make
it easy to construct a string representation of the current path.

It was originally inlined in the apex package. This change makes it a
function and moves it to the android package so make it more useful.

Bug: N/A
Test: m
Change-Id: I7e2bc2074baed759d67d9097151c9ac10e34ed31

android/module.go

@@ -19,6 +19,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"text/scanner"
 
@@ -135,6 +136,13 @@ type BaseModuleContext interface {
 	// GetTagPath()[i] is the tag between GetWalkPath()[i] and GetWalkPath()[i+1]
 	GetTagPath() []blueprint.DependencyTag
 
+	// GetPathString is supposed to be called in visit function passed in WalkDeps()
+	// and returns a multi-line string showing the modules and dependency tags
+	// among them along the top-down dependency path from a start module to current child module.
+	// skipFirst when set to true, the output doesn't include the start module,
+	// which is already printed when this function is used along with ModuleErrorf().
+	GetPathString(skipFirst bool) string
+
 	AddMissingDependencies(missingDeps []string)
 
 	Target() Target
@@ -1734,6 +1742,41 @@ func (b *baseModuleContext) GetTagPath() []blueprint.DependencyTag {
 	return b.tagPath
 }
 
+// A regexp for removing boilerplate from BaseDependencyTag from the string representation of
+// a dependency tag.
+var tagCleaner = regexp.MustCompile(`\QBaseDependencyTag:blueprint.BaseDependencyTag{}\E(, )?`)
+
+// PrettyPrintTag returns string representation of the tag, but prefers
+// custom String() method if available.
+func PrettyPrintTag(tag blueprint.DependencyTag) string {
+	// Use tag's custom String() method if available.
+	if stringer, ok := tag.(fmt.Stringer); ok {
+		return stringer.String()
+	}
+
+	// Otherwise, get a default string representation of the tag's struct.
+	tagString := fmt.Sprintf("%#v", tag)
+
+	// Remove the boilerplate from BaseDependencyTag as it adds no value.
+	tagString = tagCleaner.ReplaceAllString(tagString, "")
+	return tagString
+}
+
+func (b *baseModuleContext) GetPathString(skipFirst bool) string {
+	sb := strings.Builder{}
+	tagPath := b.GetTagPath()
+	walkPath := b.GetWalkPath()
+	if !skipFirst {
+		sb.WriteString(walkPath[0].String())
+	}
+	for i, m := range walkPath[1:] {
+		sb.WriteString("\n")
+		sb.WriteString(fmt.Sprintf("           via tag %s\n", PrettyPrintTag(tagPath[i])))
+		sb.WriteString(fmt.Sprintf("    -> %s", m.String()))
+	}
+	return sb.String()
+}
+
 func (m *moduleContext) VisitAllModuleVariants(visit func(Module)) {
 	m.bp.VisitAllModuleVariants(func(module blueprint.Module) {
 		visit(module.(Module))

apex/apex.go

@@ -18,7 +18,6 @@ import (
 	"fmt"
 	"path"
 	"path/filepath"
-	"regexp"
 	"sort"
 	"strings"
 	"sync"
@@ -1809,24 +1808,6 @@ func (a *apexBundle) minSdkVersion(ctx android.BaseModuleContext) int {
 	return intVer
 }
 
-// A regexp for removing boilerplate from BaseDependencyTag from the string representation of
-// a dependency tag.
-var tagCleaner = regexp.MustCompile(`\QBaseDependencyTag:blueprint.BaseDependencyTag{}\E(, )?`)
-
-func PrettyPrintTag(tag blueprint.DependencyTag) string {
-	// Use tag's custom String() method if available.
-	if stringer, ok := tag.(fmt.Stringer); ok {
-		return stringer.String()
-	}
-
-	// Otherwise, get a default string representation of the tag's struct.
-	tagString := fmt.Sprintf("%#v", tag)
-
-	// Remove the boilerplate from BaseDependencyTag as it adds no value.
-	tagString = tagCleaner.ReplaceAllString(tagString, "")
-	return tagString
-}
-
 // Ensures that the dependencies are marked as available for this APEX
 func (a *apexBundle) checkApexAvailability(ctx android.ModuleContext) {
 	// Let's be practical. Availability for test, host, and the VNDK apex isn't important
@@ -1861,14 +1842,7 @@ func (a *apexBundle) checkApexAvailability(ctx android.ModuleContext) {
 		if to.AvailableFor(apexName) || whitelistedApexAvailable(apexName, toName) {
 			return true
 		}
-		message := ""
+		ctx.ModuleErrorf("%q requires %q that is not available for the APEX. Dependency path:%s", fromName, toName, ctx.GetPathString(true))
-		tagPath := ctx.GetTagPath()
-		// Skip the first module as that will be added at the start of the error message by ctx.ModuleErrorf().
-		walkPath := ctx.GetWalkPath()[1:]
-		for i, m := range walkPath {
-			message = fmt.Sprintf("%s\n           via tag %s\n    -> %s", message, PrettyPrintTag(tagPath[i]), m.String())
-		}
-		ctx.ModuleErrorf("%q requires %q that is not available for the APEX. Dependency path:%s", fromName, toName, message)
 		// Visit this module's dependencies to check and report any issues with their availability.
 		return true
 	})
@@ -2132,7 +2106,7 @@ func (a *apexBundle) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 						filesInfo = append(filesInfo, apexFileForPrebuiltEtc(ctx, prebuilt, depName))
 					}
 				} else if am.CanHaveApexVariants() && am.IsInstallableToApex() {
-					ctx.ModuleErrorf("unexpected tag %s for indirect dependency %q", PrettyPrintTag(depTag), depName)
+					ctx.ModuleErrorf("unexpected tag %s for indirect dependency %q", android.PrettyPrintTag(depTag), depName)
 				}
 			}
 		}