Add recovery-resources-common-* module to FsGenState

This change selectively adds the recovery-resources-common-*dpi module
to FsGenState based on the logic converted from make.

Test: m soong_generated_recovery_filesystem_test
Bug: 381888358
Change-Id: I5620b8b349728cc83d436bf5df45d836064ed1c6
diff --git a/fsgen/util.go b/fsgen/util.go
new file mode 100644
index 0000000..9ab3ad8
--- /dev/null
+++ b/fsgen/util.go
@@ -0,0 +1,60 @@
+// Copyright (C) 2024 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fsgen
+
+import (
+	"android/soong/android"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// Returns the appropriate dpi for recovery common resources selection. Replicates the logic in
+// https://cs.android.com/android/platform/superproject/main/+/main:build/make/core/Makefile;l=2536;drc=a6af369e71ded123734523ea640b97b70a557cb9
+func getDpi(ctx android.LoadHookContext) string {
+	recoveryDensity := ctx.Config().ProductVariables().PartitionVarsForSoongMigrationOnlyDoNotUse.TargetScreenDensity
+	if len(recoveryDensity) == 0 {
+		aaptPreferredConfig := ctx.Config().ProductAAPTPreferredConfig()
+		if len(aaptPreferredConfig) > 0 {
+			recoveryDensity = aaptPreferredConfig
+		} else {
+			recoveryDensity = "mdpi"
+		}
+	}
+	if !android.InList(recoveryDensity, []string{"xxxhdpi", "xxhdpi", "xhdpi", "hdpi", "mdpi"}) {
+		recoveryDensity = strings.TrimSuffix(recoveryDensity, "dpi")
+		dpiInt, err := strconv.ParseInt(recoveryDensity, 10, 64)
+		if err != nil {
+			panic(fmt.Sprintf("Error in parsing recoveryDensity: %s", err.Error()))
+		}
+		if dpiInt >= 560 {
+			recoveryDensity = "xxxhdpi"
+		} else if dpiInt >= 400 {
+			recoveryDensity = "xxhdpi"
+		} else if dpiInt >= 280 {
+			recoveryDensity = "xhdpi"
+		} else if dpiInt >= 200 {
+			recoveryDensity = "hdpi"
+		} else {
+			recoveryDensity = "mdpi"
+		}
+	}
+
+	if p := android.ExistentPathForSource(ctx, fmt.Sprintf("bootable/recovery/res-%s", recoveryDensity)); !p.Valid() {
+		recoveryDensity = "xhdpi"
+	}
+
+	return recoveryDensity
+}