[Ravenwood] Apply a common policy across all code

Some policies should apply to all code processed by hoststubgen
universally, e.g. host side JVM workarounds. Update hoststubgen to
accept multiple policy files, and make sure all existing framework jars
have this universal policy applied.

Flag: EXEMPT host test change only
Bug: 292141694
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Change-Id: Icc0e775b5ba0dd6a09768be8cda4b03cb33522a5

8 files changed, 343 insertions, 322 deletions

diff --git a/ravenwood/Android.bp b/ravenwood/Android.bp
index 0cf9ff0ab3b5..629d846212af 100644
--- a/ravenwood/Android.bp
+++ b/ravenwood/Android.bp
@@ -12,6 +12,14 @@ package {
 }
 
 filegroup {
+    name: "ravenwood-common-policies",
+    srcs: [
+        "texts/ravenwood-common-policies.txt",
+    ],
+    visibility: ["//visibility:private"],
+}
+
+filegroup {
     name: "ravenwood-services-policies",
     srcs: [
         "texts/ravenwood-services-policies.txt",
diff --git a/ravenwood/Framework.bp b/ravenwood/Framework.bp
index 07b453431751..5cb1479514a3 100644
--- a/ravenwood/Framework.bp
+++ b/ravenwood/Framework.bp
@@ -30,6 +30,7 @@ genrule_defaults {
     tools: ["hoststubgen"],
     srcs: [
         ":framework-minus-apex-for-host",
+        ":ravenwood-common-policies",
         ":ravenwood-framework-policies",
         ":ravenwood-standard-options",
         ":ravenwood-annotation-allowed-classes",
@@ -46,6 +47,7 @@ framework_minus_apex_cmd = "$(location hoststubgen) " +
     "--debug-log $(location hoststubgen_framework-minus-apex.log) " +
     "--out-jar $(location ravenwood.jar) " +
     "--in-jar $(location :framework-minus-apex-for-host) " +
+    "--policy-override-file $(location :ravenwood-common-policies) " +
     "--policy-override-file $(location :ravenwood-framework-policies) " +
     "--annotation-allowed-classes-file $(location :ravenwood-annotation-allowed-classes) "
 
@@ -180,17 +182,18 @@ java_genrule {
         "--debug-log $(location hoststubgen_services.core.log) " +
         "--stats-file $(location hoststubgen_services.core_stats.csv) " +
         "--supported-api-list-file $(location hoststubgen_services.core_apis.csv) " +
-
-        "--out-jar $(location ravenwood.jar) " +
-
         "--gen-keep-all-file $(location hoststubgen_services.core_keep_all.txt) " +
         "--gen-input-dump-file $(location hoststubgen_services.core_dump.txt) " +
 
+        "--out-jar $(location ravenwood.jar) " +
         "--in-jar $(location :services.core-for-host) " +
+
+        "--policy-override-file $(location :ravenwood-common-policies) " +
         "--policy-override-file $(location :ravenwood-services-policies) " +
         "--annotation-allowed-classes-file $(location :ravenwood-annotation-allowed-classes) ",
     srcs: [
         ":services.core-for-host",
+        ":ravenwood-common-policies",
         ":ravenwood-services-policies",
         ":ravenwood-standard-options",
         ":ravenwood-annotation-allowed-classes",
@@ -247,21 +250,20 @@ java_genrule {
         "--debug-log $(location hoststubgen_core-icu4j-for-host.log) " +
         "--stats-file $(location hoststubgen_core-icu4j-for-host_stats.csv) " +
         "--supported-api-list-file $(location hoststubgen_core-icu4j-for-host_apis.csv) " +
-
-        "--out-jar $(location ravenwood.jar) " +
-
         "--gen-keep-all-file $(location hoststubgen_core-icu4j-for-host_keep_all.txt) " +
         "--gen-input-dump-file $(location hoststubgen_core-icu4j-for-host_dump.txt) " +
 
+        "--out-jar $(location ravenwood.jar) " +
         "--in-jar $(location :core-icu4j-for-host) " +
-        "--policy-override-file $(location :icu-ravenwood-policies) " +
-        "--annotation-allowed-classes-file $(location :ravenwood-annotation-allowed-classes) ",
+
+        "--policy-override-file $(location :ravenwood-common-policies) " +
+        "--policy-override-file $(location :icu-ravenwood-policies) ",
     srcs: [
         ":core-icu4j-for-host",
 
+        ":ravenwood-common-policies",
         ":icu-ravenwood-policies",
         ":ravenwood-standard-options",
-        ":ravenwood-annotation-allowed-classes",
     ],
     out: [
         "ravenwood.jar",
diff --git a/ravenwood/texts/ravenwood-common-policies.txt b/ravenwood/texts/ravenwood-common-policies.txt
new file mode 100644
index 000000000000..08f5397730da
--- /dev/null
+++ b/ravenwood/texts/ravenwood-common-policies.txt
@@ -0,0 +1,20 @@
+# Ravenwood "policy" that should apply to all code.
+
+# Keep all AIDL interfaces
+class :aidl keepclass
+
+# Keep all feature flag implementations
+class :feature_flags keepclass
+
+# Keep all sysprops generated code implementations
+class :sysprops keepclass
+
+# Keep all resource R classes
+class :r keepclass
+
+# Support APIs not available in standard JRE
+class java.io.FileDescriptor keep
+    method getInt$ ()I @com.android.ravenwood.RavenwoodJdkPatch.getInt$
+    method setInt$ (I)V @com.android.ravenwood.RavenwoodJdkPatch.setInt$
+class java.util.LinkedHashMap keep
+    method eldest ()Ljava/util/Map$Entry; @com.android.ravenwood.RavenwoodJdkPatch.eldest
diff --git a/ravenwood/texts/ravenwood-framework-policies.txt b/ravenwood/texts/ravenwood-framework-policies.txt
index d962c8232bf7..3649f0e78f09 100644
--- a/ravenwood/texts/ravenwood-framework-policies.txt
+++ b/ravenwood/texts/ravenwood-framework-policies.txt
@@ -1,29 +1,10 @@
 # Ravenwood "policy" file for framework-minus-apex.
 
-# Keep all AIDL interfaces
-class :aidl keepclass
-
-# Keep all feature flag implementations
-class :feature_flags keepclass
-
-# Keep all sysprops generated code implementations
-class :sysprops keepclass
-
-# Keep all resource R classes
-class :r keepclass
-
 # To avoid VerifyError on nano proto files (b/324063814), we rename nano proto classes.
 # Note: The "rename" directive must use slashes (/) as a package name separator.
 rename com/.*/nano/   devicenano/
 rename android/.*/nano/   devicenano/
 
-# Support APIs not available in standard JRE
-class java.io.FileDescriptor keep
-    method getInt$ ()I @com.android.ravenwood.RavenwoodJdkPatch.getInt$
-    method setInt$ (I)V @com.android.ravenwood.RavenwoodJdkPatch.setInt$
-class java.util.LinkedHashMap keep
-    method eldest ()Ljava/util/Map$Entry; @com.android.ravenwood.RavenwoodJdkPatch.eldest
-
 # Exported to Mainline modules; cannot use annotations
 class com.android.internal.util.FastXmlSerializer keepclass
 class com.android.internal.util.FileRotator keepclass
diff --git a/ravenwood/texts/ravenwood-services-policies.txt b/ravenwood/texts/ravenwood-services-policies.txt
index 5cdb4f74d7c0..cc2fa602b3c3 100644
--- a/ravenwood/texts/ravenwood-services-policies.txt
+++ b/ravenwood/texts/ravenwood-services-policies.txt
@@ -1,7 +1 @@
 # Ravenwood "policy" file for services.core.
-
-# Keep all AIDL interfaces
-class :aidl keepclass
-
-# Keep all feature flag implementations
-class :feature_flags keepclass
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt
index 165bb5772449..6d8d7b768b91 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGen.kt
@@ -27,7 +27,7 @@ import com.android.hoststubgen.filters.ImplicitOutputFilter
 import com.android.hoststubgen.filters.KeepNativeFilter
 import com.android.hoststubgen.filters.OutputFilter
 import com.android.hoststubgen.filters.SanitizationFilter
-import com.android.hoststubgen.filters.createFilterFromTextPolicyFile
+import com.android.hoststubgen.filters.TextFileFilterPolicyParser
 import com.android.hoststubgen.filters.printAsTextPolicy
 import com.android.hoststubgen.utils.ClassFilter
 import com.android.hoststubgen.visitors.BaseAdapter
@@ -178,8 +178,10 @@ class HostStubGen(val options: HostStubGenOptions) {
 
         // Next, "text based" filter, which allows to override polices without touching
         // the target code.
-        options.policyOverrideFile.ifSet {
-            filter = createFilterFromTextPolicyFile(it, allClasses, filter)
+        if (options.policyOverrideFiles.isNotEmpty()) {
+            val parser = TextFileFilterPolicyParser(allClasses, filter)
+            options.policyOverrideFiles.forEach(parser::parse)
+            filter = parser.createOutputFilter()
         }
 
         // Apply the implicit filter.
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt
index b083d89c61d6..55e853e3e2fb 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/HostStubGenOptions.kt
@@ -100,7 +100,7 @@ class HostStubGenOptions(
         var defaultClassLoadHook: SetOnce<String?> = SetOnce(null),
         var defaultMethodCallHook: SetOnce<String?> = SetOnce(null),
 
-        var policyOverrideFile: SetOnce<String?> = SetOnce(null),
+        var policyOverrideFiles: MutableList<String> = mutableListOf(),
 
         var defaultPolicy: SetOnce<FilterPolicy> = SetOnce(FilterPolicy.Remove),
 
@@ -164,7 +164,7 @@ class HostStubGenOptions(
                         "--out-jar", "--out-impl-jar" -> ret.outJar.set(nextArg())
 
                         "--policy-override-file" ->
-                            ret.policyOverrideFile.set(nextArg())!!.ensureFileExists()
+                            ret.policyOverrideFiles.add(nextArg().ensureFileExists())
 
                         "--clean-up-on-error" -> ret.cleanUpOnError.set(true)
                         "--no-clean-up-on-error" -> ret.cleanUpOnError.set(false)
@@ -291,7 +291,7 @@ class HostStubGenOptions(
               annotationAllowedClassesFile=$annotationAllowedClassesFile,
               defaultClassLoadHook=$defaultClassLoadHook,
               defaultMethodCallHook=$defaultMethodCallHook,
-              policyOverrideFile=$policyOverrideFile,
+              policyOverrideFiles=${policyOverrideFiles.toTypedArray().contentToString()},
               defaultPolicy=$defaultPolicy,
               cleanUpOnError=$cleanUpOnError,
               enableClassChecker=$enableClassChecker,
diff --git a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/TextFileFilterPolicyParser.kt b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/TextFileFilterPolicyParser.kt
index 073b503401b5..caf80ebec0c9 100644
--- a/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/TextFileFilterPolicyParser.kt
+++ b/tools/hoststubgen/hoststubgen/src/com/android/hoststubgen/filters/TextFileFilterPolicyParser.kt
@@ -23,13 +23,10 @@ import com.android.hoststubgen.asm.toJvmClassName
 import com.android.hoststubgen.log
 import com.android.hoststubgen.normalizeTextLine
 import com.android.hoststubgen.whitespaceRegex
-import org.objectweb.asm.Opcodes
-import org.objectweb.asm.tree.ClassNode
-import java.io.BufferedReader
-import java.io.FileReader
+import java.io.File
 import java.io.PrintWriter
-import java.util.Objects
 import java.util.regex.Pattern
+import org.objectweb.asm.tree.ClassNode
 
 /**
  * Print a class node as a "keep" policy.
@@ -49,256 +46,56 @@ fun printAsTextPolicy(pw: PrintWriter, cn: ClassNode) {
     }
 }
 
-/** Return true if [access] is either public or protected. */
-private fun isVisible(access: Int): Boolean {
-    return (access and (Opcodes.ACC_PUBLIC or Opcodes.ACC_PROTECTED)) != 0
-}
-
 private const val FILTER_REASON = "file-override"
 
-/**
- * Read a given "policy" file and return as an [OutputFilter]
- */
-fun createFilterFromTextPolicyFile(
-        filename: String,
-        classes: ClassNodes,
-        fallback: OutputFilter,
-        ): OutputFilter {
-    log.i("Loading offloaded annotations from $filename ...")
-    log.withIndent {
-        val subclassFilter = SubclassFilter(classes, fallback)
-        val packageFilter = PackageFilter(subclassFilter)
-        val imf = InMemoryOutputFilter(classes, packageFilter)
-
-        var lineNo = 0
-
-        var aidlPolicy: FilterPolicyWithReason? = null
-        var featureFlagsPolicy: FilterPolicyWithReason? = null
-        var syspropsPolicy: FilterPolicyWithReason? = null
-        var rFilePolicy: FilterPolicyWithReason? = null
-        val typeRenameSpec = mutableListOf<TextFilePolicyRemapperFilter.TypeRenameSpec>()
-        val methodReplaceSpec =
-            mutableListOf<TextFilePolicyMethodReplaceFilter.MethodCallReplaceSpec>()
-
-        try {
-            BufferedReader(FileReader(filename)).use { reader ->
-                var className = ""
-
-                while (true) {
-                    var line = reader.readLine() ?: break
-                    lineNo++
-
-                    line = normalizeTextLine(line)
+private enum class SpecialClass {
+    NotSpecial,
+    Aidl,
+    FeatureFlags,
+    Sysprops,
+    RFile,
+}
 
+class TextFileFilterPolicyParser(
+    private val classes: ClassNodes,
+    fallback: OutputFilter
+) {
+    private val subclassFilter = SubclassFilter(classes, fallback)
+    private val packageFilter = PackageFilter(subclassFilter)
+    private val imf = InMemoryOutputFilter(classes, packageFilter)
+    private var aidlPolicy: FilterPolicyWithReason? = null
+    private var featureFlagsPolicy: FilterPolicyWithReason? = null
+    private var syspropsPolicy: FilterPolicyWithReason? = null
+    private var rFilePolicy: FilterPolicyWithReason? = null
+    private val typeRenameSpec = mutableListOf<TextFilePolicyRemapperFilter.TypeRenameSpec>()
+    private val methodReplaceSpec =
+        mutableListOf<TextFilePolicyMethodReplaceFilter.MethodCallReplaceSpec>()
+
+    private lateinit var currentClassName: String
+
+    /**
+     * Read a given "policy" file and return as an [OutputFilter]
+     */
+    fun parse(file: String) {
+        log.i("Loading offloaded annotations from $file ...")
+        log.withIndent {
+            var lineNo = 0
+            try {
+                File(file).forEachLine {
+                    lineNo++
+                    val line = normalizeTextLine(it)
                     if (line.isEmpty()) {
-                        continue // skip empty lines.
-                    }
-
-
-                    // TODO: Method too long, break it up.
-
-                    val fields = line.split(whitespaceRegex).toTypedArray()
-                    when (fields[0].lowercase()) {
-                        "p", "package" -> {
-                            if (fields.size < 3) {
-                                throw ParseException("Package ('p') expects 2 fields.")
-                            }
-                            val name = fields[1]
-                            val rawPolicy = fields[2]
-                            if (resolveExtendingClass(name) != null) {
-                                throw ParseException("Package can't be a super class type")
-                            }
-                            if (resolveSpecialClass(name) != SpecialClass.NotSpecial) {
-                                throw ParseException("Package can't be a special class type")
-                            }
-                            if (rawPolicy.startsWith("!")) {
-                                throw ParseException("Package can't have a substitution")
-                            }
-                            if (rawPolicy.startsWith("~")) {
-                                throw ParseException("Package can't have a class load hook")
-                            }
-                            val policy = parsePolicy(rawPolicy)
-                            if (!policy.isUsableWithClasses) {
-                                throw ParseException("Package can't have policy '$policy'")
-                            }
-                            packageFilter.addPolicy(name, policy.withReason(FILTER_REASON))
-                        }
-
-                        "c", "class" -> {
-                            if (fields.size < 3) {
-                                throw ParseException("Class ('c') expects 2 fields.")
-                            }
-                            className = fields[1]
-
-                            // superClass is set when the class name starts with a "*".
-                            val superClass = resolveExtendingClass(className)
-
-                            // :aidl, etc?
-                            val classType = resolveSpecialClass(className)
-
-                            if (fields[2].startsWith("!")) {
-                                if (classType != SpecialClass.NotSpecial) {
-                                    // We could support it, but not needed at least for now.
-                                    throw ParseException(
-                                            "Special class can't have a substitution")
-                                }
-                                // It's a redirection class.
-                                val toClass = fields[2].substring(1)
-                                imf.setRedirectionClass(className, toClass)
-                            } else if (fields[2].startsWith("~")) {
-                                if (classType != SpecialClass.NotSpecial) {
-                                    // We could support it, but not needed at least for now.
-                                    throw ParseException(
-                                            "Special class can't have a class load hook")
-                                }
-                                // It's a class-load hook
-                                val callback = fields[2].substring(1)
-                                imf.setClassLoadHook(className, callback)
-                            } else {
-                                val policy = parsePolicy(fields[2])
-                                if (!policy.isUsableWithClasses) {
-                                    throw ParseException("Class can't have policy '$policy'")
-                                }
-                                Objects.requireNonNull(className)
-
-                                when (classType) {
-                                    SpecialClass.NotSpecial -> {
-                                        // TODO: Duplicate check, etc
-                                        if (superClass == null) {
-                                            imf.setPolicyForClass(
-                                                className, policy.withReason(FILTER_REASON)
-                                            )
-                                        } else {
-                                            subclassFilter.addPolicy(superClass,
-                                                policy.withReason("extends $superClass"))
-                                        }
-                                    }
-                                    SpecialClass.Aidl -> {
-                                        if (aidlPolicy != null) {
-                                            throw ParseException(
-                                                    "Policy for AIDL classes already defined")
-                                        }
-                                        aidlPolicy = policy.withReason(
-                                                "$FILTER_REASON (special-class AIDL)")
-                                    }
-                                    SpecialClass.FeatureFlags -> {
-                                        if (featureFlagsPolicy != null) {
-                                            throw ParseException(
-                                                    "Policy for feature flags already defined")
-                                        }
-                                        featureFlagsPolicy = policy.withReason(
-                                                "$FILTER_REASON (special-class feature flags)")
-                                    }
-                                    SpecialClass.Sysprops -> {
-                                        if (syspropsPolicy != null) {
-                                            throw ParseException(
-                                                    "Policy for sysprops already defined")
-                                        }
-                                        syspropsPolicy = policy.withReason(
-                                                "$FILTER_REASON (special-class sysprops)")
-                                    }
-                                    SpecialClass.RFile -> {
-                                        if (rFilePolicy != null) {
-                                            throw ParseException(
-                                                "Policy for R file already defined")
-                                        }
-                                        rFilePolicy = policy.withReason(
-                                            "$FILTER_REASON (special-class R file)")
-                                    }
-                                }
-                            }
-                        }
-
-                        "f", "field" -> {
-                            if (fields.size < 3) {
-                                throw ParseException("Field ('f') expects 2 fields.")
-                            }
-                            val name = fields[1]
-                            val policy = parsePolicy(fields[2])
-                            if (!policy.isUsableWithFields) {
-                                throw ParseException("Field can't have policy '$policy'")
-                            }
-                            Objects.requireNonNull(className)
-
-                            // TODO: Duplicate check, etc
-                            imf.setPolicyForField(className, name, policy.withReason(FILTER_REASON))
-                        }
-
-                        "m", "method" -> {
-                            if (fields.size < 4) {
-                                throw ParseException("Method ('m') expects 3 fields.")
-                            }
-                            val name = fields[1]
-                            val signature = fields[2]
-                            val policy = parsePolicy(fields[3])
-
-                            if (!policy.isUsableWithMethods) {
-                                throw ParseException("Method can't have policy '$policy'")
-                            }
-
-                            Objects.requireNonNull(className)
-
-                            imf.setPolicyForMethod(className, name, signature,
-                                    policy.withReason(FILTER_REASON))
-                            if (policy == FilterPolicy.Substitute) {
-                                val fromName = fields[3].substring(1)
-
-                                if (fromName == name) {
-                                    throw ParseException(
-                                            "Substitution must have a different name")
-                                }
-
-                                // Set the policy for the "from" method.
-                                imf.setPolicyForMethod(className, fromName, signature,
-                                    FilterPolicy.Keep.withReason(FILTER_REASON))
-
-                                val classAndMethod = splitWithLastPeriod(fromName)
-                                if (classAndMethod != null) {
-                                    // If the substitution target contains a ".", then
-                                    // it's a method call redirect.
-                                    methodReplaceSpec.add(
-                                        TextFilePolicyMethodReplaceFilter.MethodCallReplaceSpec(
-                                            className.toJvmClassName(),
-                                            name,
-                                            signature,
-                                            classAndMethod.first.toJvmClassName(),
-                                            classAndMethod.second,
-                                        )
-                                    )
-                                } else {
-                                    // It's an in-class replace.
-                                    // ("@RavenwoodReplace" equivalent)
-                                    imf.setRenameTo(className, fromName, signature, name)
-                                }
-                            }
-                        }
-                        "r", "rename" -> {
-                            if (fields.size < 3) {
-                                throw ParseException("Rename ('r') expects 2 fields.")
-                            }
-                            // Add ".*" to make it a prefix match.
-                            val pattern = Pattern.compile(fields[1] + ".*")
-
-                            // Removing the leading /'s from the prefix. This allows
-                            // using a single '/' as an empty suffix, which is useful to have a
-                            // "negative" rename rule to avoid subsequent raname's from getting
-                            // applied. (Which is needed for services.jar)
-                            val prefix = fields[2].trimStart('/')
-
-                            typeRenameSpec += TextFilePolicyRemapperFilter.TypeRenameSpec(
-                                pattern, prefix)
-                        }
-
-                        else -> {
-                            throw ParseException("Unknown directive \"${fields[0]}\"")
-                        }
+                        return@forEachLine // skip empty lines.
                     }
+                    parseLine(line)
                 }
+            } catch (e: ParseException) {
+                throw e.withSourceInfo(file, lineNo)
             }
-        } catch (e: ParseException) {
-            throw e.withSourceInfo(filename, lineNo)
         }
+    }
 
+    fun createOutputFilter(): OutputFilter {
         var ret: OutputFilter = imf
         if (typeRenameSpec.isNotEmpty()) {
             ret = TextFilePolicyRemapperFilter(typeRenameSpec, ret)
@@ -309,54 +106,271 @@ fun createFilterFromTextPolicyFile(
 
         // Wrap the in-memory-filter with AHF.
         ret = AndroidHeuristicsFilter(
-                classes, aidlPolicy, featureFlagsPolicy, syspropsPolicy, rFilePolicy, ret)
+            classes, aidlPolicy, featureFlagsPolicy, syspropsPolicy, rFilePolicy, ret
+        )
 
         return ret
     }
-}
 
-private enum class SpecialClass {
-    NotSpecial,
-    Aidl,
-    FeatureFlags,
-    Sysprops,
-    RFile,
-}
+    private fun parseLine(line: String) {
+        val fields = line.split(whitespaceRegex).toTypedArray()
+        when (fields[0].lowercase()) {
+            "p", "package" -> parsePackage(fields)
+            "c", "class" -> parseClass(fields)
+            "f", "field" -> parseField(fields)
+            "m", "method" -> parseMethod(fields)
+            "r", "rename" -> parseRename(fields)
+            else -> throw ParseException("Unknown directive \"${fields[0]}\"")
+        }
+    }
 
-private fun resolveSpecialClass(className: String): SpecialClass {
-    if (!className.startsWith(":")) {
-        return SpecialClass.NotSpecial
+    private fun resolveSpecialClass(className: String): SpecialClass {
+        if (!className.startsWith(":")) {
+            return SpecialClass.NotSpecial
+        }
+        when (className.lowercase()) {
+            ":aidl" -> return SpecialClass.Aidl
+            ":feature_flags" -> return SpecialClass.FeatureFlags
+            ":sysprops" -> return SpecialClass.Sysprops
+            ":r" -> return SpecialClass.RFile
+        }
+        throw ParseException("Invalid special class name \"$className\"")
     }
-    when (className.lowercase()) {
-        ":aidl" -> return SpecialClass.Aidl
-        ":feature_flags" -> return SpecialClass.FeatureFlags
-        ":sysprops" -> return SpecialClass.Sysprops
-        ":r" -> return SpecialClass.RFile
+
+    private fun resolveExtendingClass(className: String): String? {
+        if (!className.startsWith("*")) {
+            return null
+        }
+        return className.substring(1)
     }
-    throw ParseException("Invalid special class name \"$className\"")
-}
 
-private fun resolveExtendingClass(className: String): String? {
-    if (!className.startsWith("*")) {
-        return null
+    private fun parsePolicy(s: String): FilterPolicy {
+        return when (s.lowercase()) {
+            "k", "keep" -> FilterPolicy.Keep
+            "t", "throw" -> FilterPolicy.Throw
+            "r", "remove" -> FilterPolicy.Remove
+            "kc", "keepclass" -> FilterPolicy.KeepClass
+            "i", "ignore" -> FilterPolicy.Ignore
+            "rdr", "redirect" -> FilterPolicy.Redirect
+            else -> {
+                if (s.startsWith("@")) {
+                    FilterPolicy.Substitute
+                } else {
+                    throw ParseException("Invalid policy \"$s\"")
+                }
+            }
+        }
     }
-    return className.substring(1)
-}
 
-private fun parsePolicy(s: String): FilterPolicy {
-    return when (s.lowercase()) {
-        "k", "keep" -> FilterPolicy.Keep
-        "t", "throw" -> FilterPolicy.Throw
-        "r", "remove" -> FilterPolicy.Remove
-        "kc", "keepclass" -> FilterPolicy.KeepClass
-        "i", "ignore" -> FilterPolicy.Ignore
-        "rdr", "redirect" -> FilterPolicy.Redirect
-        else -> {
-            if (s.startsWith("@")) {
-                FilterPolicy.Substitute
+    private fun parsePackage(fields: Array<String>) {
+        if (fields.size < 3) {
+            throw ParseException("Package ('p') expects 2 fields.")
+        }
+        val name = fields[1]
+        val rawPolicy = fields[2]
+        if (resolveExtendingClass(name) != null) {
+            throw ParseException("Package can't be a super class type")
+        }
+        if (resolveSpecialClass(name) != SpecialClass.NotSpecial) {
+            throw ParseException("Package can't be a special class type")
+        }
+        if (rawPolicy.startsWith("!")) {
+            throw ParseException("Package can't have a substitution")
+        }
+        if (rawPolicy.startsWith("~")) {
+            throw ParseException("Package can't have a class load hook")
+        }
+        val policy = parsePolicy(rawPolicy)
+        if (!policy.isUsableWithClasses) {
+            throw ParseException("Package can't have policy '$policy'")
+        }
+        packageFilter.addPolicy(name, policy.withReason(FILTER_REASON))
+    }
+
+    private fun parseClass(fields: Array<String>) {
+        if (fields.size < 3) {
+            throw ParseException("Class ('c') expects 2 fields.")
+        }
+        currentClassName = fields[1]
+
+        // superClass is set when the class name starts with a "*".
+        val superClass = resolveExtendingClass(currentClassName)
+
+        // :aidl, etc?
+        val classType = resolveSpecialClass(currentClassName)
+
+        if (fields[2].startsWith("!")) {
+            if (classType != SpecialClass.NotSpecial) {
+                // We could support it, but not needed at least for now.
+                throw ParseException(
+                    "Special class can't have a substitution"
+                )
+            }
+            // It's a redirection class.
+            val toClass = fields[2].substring(1)
+            imf.setRedirectionClass(currentClassName, toClass)
+        } else if (fields[2].startsWith("~")) {
+            if (classType != SpecialClass.NotSpecial) {
+                // We could support it, but not needed at least for now.
+                throw ParseException(
+                    "Special class can't have a class load hook"
+                )
+            }
+            // It's a class-load hook
+            val callback = fields[2].substring(1)
+            imf.setClassLoadHook(currentClassName, callback)
+        } else {
+            val policy = parsePolicy(fields[2])
+            if (!policy.isUsableWithClasses) {
+                throw ParseException("Class can't have policy '$policy'")
+            }
+
+            when (classType) {
+                SpecialClass.NotSpecial -> {
+                    // TODO: Duplicate check, etc
+                    if (superClass == null) {
+                        imf.setPolicyForClass(
+                            currentClassName, policy.withReason(FILTER_REASON)
+                        )
+                    } else {
+                        subclassFilter.addPolicy(
+                            superClass,
+                            policy.withReason("extends $superClass")
+                        )
+                    }
+                }
+
+                SpecialClass.Aidl -> {
+                    if (aidlPolicy != null) {
+                        throw ParseException(
+                            "Policy for AIDL classes already defined"
+                        )
+                    }
+                    aidlPolicy = policy.withReason(
+                        "$FILTER_REASON (special-class AIDL)"
+                    )
+                }
+
+                SpecialClass.FeatureFlags -> {
+                    if (featureFlagsPolicy != null) {
+                        throw ParseException(
+                            "Policy for feature flags already defined"
+                        )
+                    }
+                    featureFlagsPolicy = policy.withReason(
+                        "$FILTER_REASON (special-class feature flags)"
+                    )
+                }
+
+                SpecialClass.Sysprops -> {
+                    if (syspropsPolicy != null) {
+                        throw ParseException(
+                            "Policy for sysprops already defined"
+                        )
+                    }
+                    syspropsPolicy = policy.withReason(
+                        "$FILTER_REASON (special-class sysprops)"
+                    )
+                }
+
+                SpecialClass.RFile -> {
+                    if (rFilePolicy != null) {
+                        throw ParseException(
+                            "Policy for R file already defined"
+                        )
+                    }
+                    rFilePolicy = policy.withReason(
+                        "$FILTER_REASON (special-class R file)"
+                    )
+                }
+            }
+        }
+    }
+
+    private fun parseField(fields: Array<String>) {
+        if (fields.size < 3) {
+            throw ParseException("Field ('f') expects 2 fields.")
+        }
+        val name = fields[1]
+        val policy = parsePolicy(fields[2])
+        if (!policy.isUsableWithFields) {
+            throw ParseException("Field can't have policy '$policy'")
+        }
+        require(this::currentClassName.isInitialized)
+
+        // TODO: Duplicate check, etc
+        imf.setPolicyForField(currentClassName, name, policy.withReason(FILTER_REASON))
+    }
+
+    private fun parseMethod(fields: Array<String>) {
+        if (fields.size < 4) {
+            throw ParseException("Method ('m') expects 3 fields.")
+        }
+        val name = fields[1]
+        val signature = fields[2]
+        val policy = parsePolicy(fields[3])
+
+        if (!policy.isUsableWithMethods) {
+            throw ParseException("Method can't have policy '$policy'")
+        }
+
+        require(this::currentClassName.isInitialized)
+
+        imf.setPolicyForMethod(
+            currentClassName, name, signature,
+            policy.withReason(FILTER_REASON)
+        )
+        if (policy == FilterPolicy.Substitute) {
+            val fromName = fields[3].substring(1)
+
+            if (fromName == name) {
+                throw ParseException(
+                    "Substitution must have a different name"
+                )
+            }
+
+            // Set the policy for the "from" method.
+            imf.setPolicyForMethod(
+                currentClassName, fromName, signature,
+                FilterPolicy.Keep.withReason(FILTER_REASON)
+            )
+
+            val classAndMethod = splitWithLastPeriod(fromName)
+            if (classAndMethod != null) {
+                // If the substitution target contains a ".", then
+                // it's a method call redirect.
+                methodReplaceSpec.add(
+                    TextFilePolicyMethodReplaceFilter.MethodCallReplaceSpec(
+                        currentClassName.toJvmClassName(),
+                        name,
+                        signature,
+                        classAndMethod.first.toJvmClassName(),
+                        classAndMethod.second,
+                    )
+                )
             } else {
-                throw ParseException("Invalid policy \"$s\"")
+                // It's an in-class replace.
+                // ("@RavenwoodReplace" equivalent)
+                imf.setRenameTo(currentClassName, fromName, signature, name)
             }
         }
     }
+
+    private fun parseRename(fields: Array<String>) {
+        if (fields.size < 3) {
+            throw ParseException("Rename ('r') expects 2 fields.")
+        }
+        // Add ".*" to make it a prefix match.
+        val pattern = Pattern.compile(fields[1] + ".*")
+
+        // Removing the leading /'s from the prefix. This allows
+        // using a single '/' as an empty suffix, which is useful to have a
+        // "negative" rename rule to avoid subsequent raname's from getting
+        // applied. (Which is needed for services.jar)
+        val prefix = fields[2].trimStart('/')
+
+        typeRenameSpec += TextFilePolicyRemapperFilter.TypeRenameSpec(
+            pattern, prefix
+        )
+    }
 }