A tool to facilitate large ninja files comparison.
Bug: 201713929
Test: internal
Change-Id: Ifd976eed1e58b7409e3deacf99917206f0149ade
diff --git a/tools/canoninja/canoninja.go b/tools/canoninja/canoninja.go
new file mode 100644
index 0000000..681a694
--- /dev/null
+++ b/tools/canoninja/canoninja.go
@@ -0,0 +1,130 @@
+package canoninja
+
+import (
+ "bytes"
+ "crypto/sha1"
+ "encoding/hex"
+ "fmt"
+ "io"
+)
+
+var (
+ rulePrefix = []byte("rule ")
+ buildPrefix = []byte("build ")
+ phonyRule = []byte("phony")
+)
+
+func Generate(path string, buffer []byte, sink io.Writer) error {
+ // Break file into lines
+ from := 0
+ var lines [][]byte
+ for from < len(buffer) {
+ line := getLine(buffer[from:])
+ lines = append(lines, line)
+ from += len(line)
+ }
+
+ // FOr each rule, calculate and remember its digest
+ ruleDigest := make(map[string]string)
+ for i := 0; i < len(lines); {
+ if bytes.HasPrefix(lines[i], rulePrefix) {
+ // Find ruleName
+ rn := ruleName(lines[i])
+ if len(rn) == 0 {
+ return fmt.Errorf("%s:%d: rule name is missing or on the next line", path, i+1)
+ }
+ sRuleName := string(rn)
+ if _, ok := ruleDigest[sRuleName]; ok {
+ return fmt.Errorf("%s:%d: the rule %s has been already defined", path, i+1, sRuleName)
+ }
+ // Calculate rule text digest as a digests of line digests.
+ var digests []byte
+ doDigest := func(b []byte) {
+ h := sha1.New()
+ h.Write(b)
+ digests = h.Sum(digests)
+
+ }
+ // For the first line, digest everything after rule's name
+ doDigest(lines[i][cap(lines[i])+len(rn)-cap(rn):])
+ for i++; i < len(lines) && lines[i][0] == ' '; i++ {
+ doDigest(lines[i])
+ }
+ h := sha1.New()
+ h.Write(digests)
+ ruleDigest[sRuleName] = "R" + hex.EncodeToString(h.Sum(nil))
+
+ } else {
+ i++
+ }
+ }
+
+ // Rewrite rule names.
+ for i, line := range lines {
+ if bytes.HasPrefix(line, buildPrefix) {
+ brn := getBuildRuleName(line)
+ if bytes.Equal(brn, phonyRule) {
+ sink.Write(line)
+ continue
+ }
+ if len(brn) == 0 {
+ return fmt.Errorf("%s:%d: build statement lacks rule name", path, i+1)
+ }
+ sink.Write(line[0 : cap(line)-cap(brn)])
+ if digest, ok := ruleDigest[string(brn)]; ok {
+ sink.Write([]byte(digest))
+ } else {
+ return fmt.Errorf("%s:%d: no rule for this build target", path, i+1)
+ }
+ sink.Write(line[cap(line)+len(brn)-cap(brn):])
+ } else if bytes.HasPrefix(line, rulePrefix) {
+ rn := ruleName(line)
+ // Write everything before it
+ sink.Write(line[0 : cap(line)-cap(rn)])
+ sink.Write([]byte(ruleDigest[string(rn)]))
+ sink.Write(line[cap(line)+len(rn)-cap(rn):])
+ } else {
+ //goland:noinspection GoUnhandledErrorResult
+ sink.Write(line)
+ }
+ }
+ return nil
+}
+
+func getLine(b []byte) []byte {
+ if n := bytes.IndexByte(b, '\n'); n >= 0 {
+ return b[:n+1]
+ }
+ return b
+}
+
+// Returns build statement's rule name
+func getBuildRuleName(line []byte) []byte {
+ n := bytes.IndexByte(line, ':')
+ if n <= 0 {
+ return nil
+ }
+ ruleName := line[n+1:]
+ if ruleName[0] == ' ' {
+ ruleName = bytes.TrimLeft(ruleName, " ")
+ }
+ if n := bytes.IndexAny(ruleName, " \t\r\n"); n >= 0 {
+ ruleName = ruleName[0:n]
+ }
+ return ruleName
+}
+
+// Returns rule statement's rule name
+func ruleName(lineAfterRule []byte) []byte {
+ ruleName := lineAfterRule[len(rulePrefix):]
+ if len(ruleName) == 0 {
+ return ruleName
+ }
+ if ruleName[0] == ' ' {
+ ruleName = bytes.TrimLeft(ruleName, " ")
+ }
+ if n := bytes.IndexAny(ruleName, " \t\r\n"); n >= 0 {
+ ruleName = ruleName[0:n]
+ }
+ return ruleName
+}