Create a synthetic Bazel workspace.
It's under out/soong/workspace and is a symlink forest that merges BUILD
files generated by bp2build and the source tree.
bazel-* symlinks and $OUTDIR are currently ignored.
Test: Presubmits.
Change-Id: If14df23bd0f6a6f2d7d1140f95213f2aee66d652
diff --git a/bp2build/Android.bp b/bp2build/Android.bp
index d2a8729..abd79f5 100644
--- a/bp2build/Android.bp
+++ b/bp2build/Android.bp
@@ -14,6 +14,7 @@
"constants.go",
"conversion.go",
"metrics.go",
+ "symlink_forest.go",
],
deps: [
"soong-android",
diff --git a/bp2build/conversion_test.go b/bp2build/conversion_test.go
index 9fd6817..262a488 100644
--- a/bp2build/conversion_test.go
+++ b/bp2build/conversion_test.go
@@ -19,14 +19,14 @@
"testing"
)
-type filepath struct {
+type bazelFilepath struct {
dir string
basename string
}
func TestCreateBazelFiles_QueryView_AddsTopLevelFiles(t *testing.T) {
files := CreateBazelFiles(map[string]RuleShim{}, map[string]BazelTargets{}, QueryView)
- expectedFilePaths := []filepath{
+ expectedFilePaths := []bazelFilepath{
{
dir: "",
basename: "BUILD",
diff --git a/bp2build/symlink_forest.go b/bp2build/symlink_forest.go
new file mode 100644
index 0000000..80ad3b6
--- /dev/null
+++ b/bp2build/symlink_forest.go
@@ -0,0 +1,189 @@
+package bp2build
+
+import (
+ "fmt"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+
+ "android/soong/shared"
+)
+
+// A tree structure that describes what to do at each directory in the created
+// symlink tree. Currently it is used to enumerate which files/directories
+// should be excluded from symlinking. Each instance of "node" represents a file
+// or a directory. If excluded is true, then that file/directory should be
+// excluded from symlinking. Otherwise, the node is not excluded, but one of its
+// descendants is (otherwise the node in question would not exist)
+type node struct {
+ name string
+ excluded bool // If false, this is just an intermediate node
+ children map[string]*node
+}
+
+// Ensures that the a node for the given path exists in the tree and returns it.
+func ensureNodeExists(root *node, path string) *node {
+ if path == "" {
+ return root
+ }
+
+ if path[len(path)-1] == '/' {
+ path = path[:len(path)-1] // filepath.Split() leaves a trailing slash
+ }
+
+ dir, base := filepath.Split(path)
+
+ // First compute the parent node...
+ dn := ensureNodeExists(root, dir)
+
+ // then create the requested node as its direct child, if needed.
+ if child, ok := dn.children[base]; ok {
+ return child
+ } else {
+ dn.children[base] = &node{base, false, make(map[string]*node)}
+ return dn.children[base]
+ }
+}
+
+// Turns a list of paths to be excluded into a tree made of "node" objects where
+// the specified paths are marked as excluded.
+func treeFromExcludePathList(paths []string) *node {
+ result := &node{"", false, make(map[string]*node)}
+
+ for _, p := range paths {
+ ensureNodeExists(result, p).excluded = true
+ }
+
+ return result
+}
+
+// Calls readdir() and returns it as a map from the basename of the files in dir
+// to os.FileInfo.
+func readdirToMap(dir string) map[string]os.FileInfo {
+ entryList, err := ioutil.ReadDir(dir)
+ result := make(map[string]os.FileInfo)
+
+ if err != nil {
+ if os.IsNotExist(err) {
+ // It's okay if a directory doesn't exist; it just means that one of the
+ // trees to be merged contains parts the other doesn't
+ return result
+ } else {
+ fmt.Fprintf(os.Stderr, "Cannot readdir '%s': %s\n", dir, err)
+ os.Exit(1)
+ }
+ }
+
+ for _, fi := range entryList {
+ result[fi.Name()] = fi
+ }
+
+ return result
+}
+
+// Creates a symbolic link at dst pointing to src
+func symlinkIntoForest(topdir, dst, src string) {
+ err := os.Symlink(shared.JoinPath(topdir, src), shared.JoinPath(topdir, dst))
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "Cannot create symlink at '%s' pointing to '%s': %s", dst, src, err)
+ os.Exit(1)
+ }
+}
+
+// Recursively plants a symlink forest at forestDir. The symlink tree will
+// contain every file in buildFilesDir and srcDir excluding the files in
+// exclude. Collects every directory encountered during the traversal of srcDir
+// into acc.
+func plantSymlinkForestRecursive(topdir string, forestDir string, buildFilesDir string, srcDir string, exclude *node, acc *[]string) {
+ if exclude != nil && exclude.excluded {
+ // This directory is not needed, bail out
+ return
+ }
+
+ *acc = append(*acc, srcDir)
+ srcDirMap := readdirToMap(shared.JoinPath(topdir, srcDir))
+ buildFilesMap := readdirToMap(shared.JoinPath(topdir, buildFilesDir))
+
+ allEntries := make(map[string]bool)
+ for n, _ := range srcDirMap {
+ allEntries[n] = true
+ }
+
+ for n, _ := range buildFilesMap {
+ allEntries[n] = true
+ }
+
+ err := os.MkdirAll(shared.JoinPath(topdir, forestDir), 0777)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "Cannot mkdir '%s': %s\n", forestDir, err)
+ os.Exit(1)
+ }
+
+ for f, _ := range allEntries {
+ if f[0] == '.' {
+ continue // Ignore dotfiles
+ }
+
+ // The full paths of children in the input trees and in the output tree
+ fp := shared.JoinPath(forestDir, f)
+ sp := shared.JoinPath(srcDir, f)
+ bp := shared.JoinPath(buildFilesDir, f)
+
+ // Descend in the exclusion tree, if there are any excludes left
+ var ce *node
+ if exclude == nil {
+ ce = nil
+ } else {
+ ce = exclude.children[f]
+ }
+
+ sf, sExists := srcDirMap[f]
+ bf, bExists := buildFilesMap[f]
+ excluded := ce != nil && ce.excluded
+
+ if excluded {
+ continue
+ }
+
+ if !sExists {
+ if bf.IsDir() && ce != nil {
+ // Not in the source tree, but we have to exclude something from under
+ // this subtree, so descend
+ plantSymlinkForestRecursive(topdir, fp, bp, sp, ce, acc)
+ } else {
+ // Not in the source tree, symlink BUILD file
+ symlinkIntoForest(topdir, fp, bp)
+ }
+ } else if !bExists {
+ if sf.IsDir() && ce != nil {
+ // Not in the build file tree, but we have to exclude something from
+ // under this subtree, so descend
+ plantSymlinkForestRecursive(topdir, fp, bp, sp, ce, acc)
+ } else {
+ // Not in the build file tree, symlink source tree, carry on
+ symlinkIntoForest(topdir, fp, sp)
+ }
+ } else if sf.IsDir() && bf.IsDir() {
+ // Both are directories. Descend.
+ plantSymlinkForestRecursive(topdir, fp, bp, sp, ce, acc)
+ } else {
+ // Both exist and one is a file. This is an error.
+ fmt.Fprintf(os.Stderr,
+ "Conflict in workspace symlink tree creation: both '%s' and '%s' exist and at least one of them is a file\n",
+ sp, bp)
+ os.Exit(1)
+ }
+ }
+}
+
+// Creates a symlink forest by merging the directory tree at "buildFiles" and
+// "srcDir" while excluding paths listed in "exclude". Returns the set of paths
+// under srcDir on which readdir() had to be called to produce the symlink
+// forest.
+func PlantSymlinkForest(topdir string, forest string, buildFiles string, srcDir string, exclude []string) []string {
+ deps := make([]string, 0)
+ os.RemoveAll(shared.JoinPath(topdir, forest))
+ excludeTree := treeFromExcludePathList(exclude)
+ plantSymlinkForestRecursive(topdir, forest, buildFiles, srcDir, excludeTree, &deps)
+ return deps
+}