Shard rust protobuf sources

Shorten the command line for generating rust protobuf sources
by sharding the sources into groups of 50 source files.

Bug: 322564768
Bug: 336323108
Test: builds
Change-Id: Ia8069cdaf49f9a42d14a83139545ba61277418e0

rust/protobuf.go

@@ -16,6 +16,7 @@ package rust
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 
 	"android/soong/android"
@@ -122,9 +123,10 @@ func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps)
 	// stemFile must be first here as the first path in BaseSourceProvider.OutputFiles is the library entry-point.
 	var outputs android.WritablePaths
 
+	for i, shard := range android.ShardPaths(protoFiles, 50) {
 		rule := android.NewRuleBuilder(pctx, ctx)
 
-	for _, protoFile := range protoFiles {
+		for _, protoFile := range shard {
 			// Since we're iterating over the protoFiles already, make sure they're not redeclared in grpcFiles
 			if android.InList(protoFile.String(), grpcFiles.Strings()) {
 				ctx.PropertyErrorf("protos",
@@ -144,7 +146,20 @@ func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps)
 			outputs = append(outputs, ruleOutputs...)
 		}
 
-	for _, grpcFile := range grpcFiles {
+		ruleName := "protoc"
+		ruleDesc := "protoc"
+		if i > 0 {
+			ruleName += "_" + strconv.Itoa(i+1)
+			ruleDesc += " " + strconv.Itoa(i+1)
+		}
+
+		rule.Build(ruleName, ruleDesc)
+	}
+
+	for i, shard := range android.ShardPaths(grpcFiles, 50) {
+		rule := android.NewRuleBuilder(pctx, ctx)
+
+		for _, grpcFile := range shard {
 			grpcName := strings.TrimSuffix(grpcFile.Base(), ".proto")
 			proto.grpcNames = append(proto.grpcNames, grpcName)
 
@@ -159,6 +174,16 @@ func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps)
 			outputs = append(outputs, ruleOutputs...)
 		}
 
+		ruleName := "protoc_grpc"
+		ruleDesc := "protoc grpc"
+		if i > 0 {
+			ruleName += "_" + strconv.Itoa(i+1)
+			ruleDesc += " " + strconv.Itoa(i+1)
+		}
+
+		rule.Build(ruleName, ruleDesc)
+	}
+
 	// Check that all proto base filenames are unique as outputs are written to the same directory.
 	baseFilenames := append(proto.protoNames, proto.grpcNames...)
 	if len(baseFilenames) != len(android.FirstUniqueStrings(baseFilenames)) {
@@ -168,8 +193,6 @@ func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps)
 
 	android.WriteFileRule(ctx, stemFile, proto.genModFileContents())
 
-	rule.Build("protoc_"+ctx.ModuleName(), "protoc "+ctx.ModuleName())
-
 	// stemFile must be first here as the first path in BaseSourceProvider.OutputFiles is the library entry-point.
 	proto.BaseSourceProvider.OutputFiles = append(android.Paths{stemFile}, outputs.Paths()...)