Create Bazel symlink forest in a separate process.
This helps with incrementality a lot: the symlink forest must depend on
almost every directory in the source tree so that if a new file is added
or removed from *anywhere*, it is regenerated.
Previously, we couldn't do this without invoking bp2build, which is
quite wasteful because bp2build takes way more time than the symlink
forest creation, even though we do the latter in a very suboptimal way
at the moment.
This means that if a source file is added or removed (which does not
affect globs), we don't pay the cost of bp2build anymore.
Also refactored symlink_forest.go on the side. Too much state was being
passed around in arguments.
This change reimplements aosp/2263423 ; the semantics of not touching an
output file is the exact same as order-only inputs and the latter is a
bit fewer lines of code.
Test: Presubmits.
Change-Id: I565c580df8a01bacf175d56747c3f50743d4a4d4
diff --git a/bp2build/symlink_forest.go b/bp2build/symlink_forest.go
index 092b240..e2b99c4 100644
--- a/bp2build/symlink_forest.go
+++ b/bp2build/symlink_forest.go
@@ -21,7 +21,6 @@
"path/filepath"
"regexp"
- "android/soong/android"
"android/soong/shared"
)
@@ -31,14 +30,22 @@
// 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 {
+
+type instructionsNode struct {
name string
excluded bool // If false, this is just an intermediate node
- children map[string]*node
+ children map[string]*instructionsNode
+}
+
+type symlinkForestContext struct {
+ verbose bool
+ topdir string // $TOPDIR
+ deps []string // Files/directories read while constructing the forest
+ okay bool // Whether the forest was successfully constructed
}
// Ensures that the node for the given path exists in the tree and returns it.
-func ensureNodeExists(root *node, path string) *node {
+func ensureNodeExists(root *instructionsNode, path string) *instructionsNode {
if path == "" {
return root
}
@@ -56,15 +63,14 @@
if child, ok := dn.children[base]; ok {
return child
} else {
- dn.children[base] = &node{base, false, make(map[string]*node)}
+ dn.children[base] = &instructionsNode{base, false, make(map[string]*instructionsNode)}
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)}
+// Turns a list of paths to be excluded into a tree
+func instructionsFromExcludePathList(paths []string) *instructionsNode {
+ result := &instructionsNode{"", false, make(map[string]*instructionsNode)}
for _, p := range paths {
ensureNodeExists(result, p).excluded = true
@@ -179,17 +185,21 @@
// 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(cfg android.Config, topdir string, forestDir string, buildFilesDir string, srcDir string, exclude *node, acc *[]string, okay *bool) {
- if exclude != nil && exclude.excluded {
+// instructions. Collects every directory encountered during the traversal of
+// srcDir .
+func plantSymlinkForestRecursive(context *symlinkForestContext, instructions *instructionsNode, forestDir string, buildFilesDir string, srcDir string) {
+ if instructions != nil && instructions.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))
+ // We don't add buildFilesDir here because the bp2build files marker files is
+ // already a dependency which covers it. If we ever wanted to turn this into
+ // a generic symlink forest creation tool, we'd need to add it, too.
+ context.deps = append(context.deps, srcDir)
+
+ srcDirMap := readdirToMap(shared.JoinPath(context.topdir, srcDir))
+ buildFilesMap := readdirToMap(shared.JoinPath(context.topdir, buildFilesDir))
renamingBuildFile := false
if _, ok := srcDirMap["BUILD"]; ok {
@@ -211,7 +221,7 @@
allEntries[n] = struct{}{}
}
- err := os.MkdirAll(shared.JoinPath(topdir, forestDir), 0777)
+ err := os.MkdirAll(shared.JoinPath(context.topdir, forestDir), 0777)
if err != nil {
fmt.Fprintf(os.Stderr, "Cannot mkdir '%s': %s\n", forestDir, err)
os.Exit(1)
@@ -230,69 +240,69 @@
}
buildFilesChild := shared.JoinPath(buildFilesDir, f)
- // Descend in the exclusion tree, if there are any excludes left
- var excludeChild *node = nil
- if exclude != nil {
+ // Descend in the instruction tree if it exists
+ var instructionsChild *instructionsNode = nil
+ if instructions != nil {
if f == "BUILD.bazel" && renamingBuildFile {
- excludeChild = exclude.children["BUILD"]
+ instructionsChild = instructions.children["BUILD"]
} else {
- excludeChild = exclude.children[f]
+ instructionsChild = instructions.children[f]
}
}
srcChildEntry, sExists := srcDirMap[f]
buildFilesChildEntry, bExists := buildFilesMap[f]
- if excludeChild != nil && excludeChild.excluded {
+ if instructionsChild != nil && instructionsChild.excluded {
if bExists {
- symlinkIntoForest(topdir, forestChild, buildFilesChild)
+ symlinkIntoForest(context.topdir, forestChild, buildFilesChild)
}
continue
}
- sDir := sExists && isDir(shared.JoinPath(topdir, srcChild), srcChildEntry)
- bDir := bExists && isDir(shared.JoinPath(topdir, buildFilesChild), buildFilesChildEntry)
+ sDir := sExists && isDir(shared.JoinPath(context.topdir, srcChild), srcChildEntry)
+ bDir := bExists && isDir(shared.JoinPath(context.topdir, buildFilesChild), buildFilesChildEntry)
if !sExists {
- if bDir && excludeChild != nil {
+ if bDir && instructionsChild != nil {
// Not in the source tree, but we have to exclude something from under
// this subtree, so descend
- plantSymlinkForestRecursive(cfg, topdir, forestChild, buildFilesChild, srcChild, excludeChild, acc, okay)
+ plantSymlinkForestRecursive(context, instructionsChild, forestChild, buildFilesChild, srcChild)
} else {
// Not in the source tree, symlink BUILD file
- symlinkIntoForest(topdir, forestChild, buildFilesChild)
+ symlinkIntoForest(context.topdir, forestChild, buildFilesChild)
}
} else if !bExists {
- if sDir && excludeChild != nil {
+ if sDir && instructionsChild != nil {
// Not in the build file tree, but we have to exclude something from
// under this subtree, so descend
- plantSymlinkForestRecursive(cfg, topdir, forestChild, buildFilesChild, srcChild, excludeChild, acc, okay)
+ plantSymlinkForestRecursive(context, instructionsChild, forestChild, buildFilesChild, srcChild)
} else {
// Not in the build file tree, symlink source tree, carry on
- symlinkIntoForest(topdir, forestChild, srcChild)
+ symlinkIntoForest(context.topdir, forestChild, srcChild)
}
} else if sDir && bDir {
// Both are directories. Descend.
- plantSymlinkForestRecursive(cfg, topdir, forestChild, buildFilesChild, srcChild, excludeChild, acc, okay)
+ plantSymlinkForestRecursive(context, instructionsChild, forestChild, buildFilesChild, srcChild)
} else if !sDir && !bDir {
// Neither is a directory. Merge them.
- srcBuildFile := shared.JoinPath(topdir, srcChild)
- generatedBuildFile := shared.JoinPath(topdir, buildFilesChild)
+ srcBuildFile := shared.JoinPath(context.topdir, srcChild)
+ generatedBuildFile := shared.JoinPath(context.topdir, buildFilesChild)
// The Android.bp file that codegen used to produce `buildFilesChild` is
// already a dependency, we can ignore `buildFilesChild`.
- *acc = append(*acc, srcChild)
- err = mergeBuildFiles(shared.JoinPath(topdir, forestChild), srcBuildFile, generatedBuildFile, cfg.IsEnvTrue("BP2BUILD_VERBOSE"))
+ context.deps = append(context.deps, srcChild)
+ err = mergeBuildFiles(shared.JoinPath(context.topdir, forestChild), srcBuildFile, generatedBuildFile, context.verbose)
if err != nil {
fmt.Fprintf(os.Stderr, "Error merging %s and %s: %s",
srcBuildFile, generatedBuildFile, err)
- *okay = false
+ context.okay = false
}
} 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 exactly one is a directory\n",
srcChild, buildFilesChild)
- *okay = false
+ context.okay = false
}
}
}
@@ -301,14 +311,20 @@
// "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(cfg android.Config, topdir string, forest string, buildFiles string, srcDir string, exclude []string) []string {
- deps := make([]string, 0)
+func PlantSymlinkForest(verbose bool, topdir string, forest string, buildFiles string, exclude []string) []string {
+ context := &symlinkForestContext{
+ verbose: verbose,
+ topdir: topdir,
+ deps: make([]string, 0),
+ okay: true,
+ }
+
os.RemoveAll(shared.JoinPath(topdir, forest))
- excludeTree := treeFromExcludePathList(exclude)
- okay := true
- plantSymlinkForestRecursive(cfg, topdir, forest, buildFiles, srcDir, excludeTree, &deps, &okay)
- if !okay {
+
+ instructions := instructionsFromExcludePathList(exclude)
+ plantSymlinkForestRecursive(context, instructions, forest, buildFiles, ".")
+ if !context.okay {
os.Exit(1)
}
- return deps
+ return context.deps
}