Limit the number of the Java source files in a single compilation unit

KYTHE_JAVA_SOURCE_BATCH_SIZE environment variable controls this setting.
The limit is 1000 if this variable is not set.

Fixes: 179932118
Test: run prebuilts/build-tools/build-prebuilts.sh, use it to build kzips, check
Change-Id: I9ad57dfd1d2c2dce5cff755b1bd61cf933420bd3

android/config.go

@@ -24,6 +24,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -911,6 +912,25 @@ func (c *config) XrefCuEncoding() string {
 	return "json"
 }
 
+// XrefCuJavaSourceMax returns the maximum number of the Java source files
+// in a single compilation unit
+const xrefJavaSourceFileMaxDefault = "1000"
+
+func (c Config) XrefCuJavaSourceMax() string {
+	v := c.Getenv("KYTHE_JAVA_SOURCE_BATCH_SIZE")
+	if v == "" {
+		return xrefJavaSourceFileMaxDefault
+	}
+	if _, err := strconv.ParseUint(v, 0, 0); err != nil {
+		fmt.Fprintf(os.Stderr,
+			"bad KYTHE_JAVA_SOURCE_BATCH_SIZE value: %s, will use %s",
+			err, xrefJavaSourceFileMaxDefault)
+		return xrefJavaSourceFileMaxDefault
+	}
+	return v
+
+}
+
 func (c *config) EmitXrefRules() bool {
 	return c.XrefCorpusName() != ""
 }

build_kzip.bash

@@ -7,14 +7,16 @@
 #   BUILD_NUMBER          build number, used to generate unique ID (will use UUID if not set)
 #   DIST_DIR              where the resulting all.kzip will be placed
 #   KYTHE_KZIP_ENCODING   proto or json (proto is default)
+#   KYTHE_JAVA_SOURCE_BATCH_SIZE maximum number of the Java source files in a compilation unit
 #   OUT_DIR               output directory (out if not specified})
 #   TARGET_BUILD_VARIANT  variant, e.g., `userdebug`
 #   TARGET_PRODUCT        target device name, e.g., 'aosp_blueline'
 #   XREF_CORPUS           source code repository URI, e.g., 'android.googlesource.com/platform/superproject'
 
 : ${BUILD_NUMBER:=$(uuidgen)}
+: ${KYTHE_JAVA_SOURCE_BATCH_SIZE:=500}
 : ${KYTHE_KZIP_ENCODING:=proto}
-export KYTHE_KZIP_ENCODING
+export KYTHE_JAVA_SOURCE_BATCH_SIZE KYTHE_KZIP_ENCODING
 
 # The extraction might fail for some source files, so run with -k and then check that
 # sufficiently many files were generated.

java/builder.go

@@ -80,6 +80,8 @@ var (
 		func(ctx android.PackageVarContext) string { return ctx.Config().XrefCorpusName() })
 	_ = pctx.VariableFunc("kytheCuEncoding",
 		func(ctx android.PackageVarContext) string { return ctx.Config().XrefCuEncoding() })
+	_ = pctx.VariableFunc("kytheCuJavaSourceMax",
+		func(ctx android.PackageVarContext) string { return ctx.Config().XrefCuJavaSourceMax() })
 	_ = pctx.SourcePathVariable("kytheVnames", "build/soong/vnames.json")
 	// Run it with -add-opens=java.base/java.nio=ALL-UNNAMED to avoid JDK9's warning about
 	// "Illegal reflective access by com.google.protobuf.Utf8$UnsafeProcessor ...
@@ -93,6 +95,7 @@ var (
 				`KYTHE_CORPUS=${kytheCorpus} ` +
 				`KYTHE_VNAMES=${kytheVnames} ` +
 				`KYTHE_KZIP_ENCODING=${kytheCuEncoding} ` +
+				`KYTHE_JAVA_SOURCE_BATCH_SIZE=${kytheCuJavaSourceMax} ` +
 				`${config.SoongJavacWrapper} ${config.JavaCmd} ` +
 				`--add-opens=java.base/java.nio=ALL-UNNAMED ` +
 				`-jar ${config.JavaKytheExtractorJar} ` +