ffi: autogen java bindings (very wip)

ffi/build.gradle.kts

@@ -3,6 +3,7 @@ plugins {
 }
 
 dependencies {
+  api(project(":frontend"))
   api(project(":evaluator"))
 
   implementation(project(":common"))

ffi/src/main/kotlin/gay/pizza/pork/ffi/JavaAutogen.kt

@@ -0,0 +1,94 @@
+package gay.pizza.pork.ffi
+
+import gay.pizza.pork.ast.*
+import java.io.PrintStream
+import java.lang.reflect.Modifier
+
+class JavaAutogen(val javaClass: Class<*>) {
+  private val prefix = javaClass.name.replace(".", "_")
+
+  fun generateCompilationUnit(): CompilationUnit {
+    return CompilationUnit(
+      declarations = listOf(),
+      definitions = generateFunctionDefinitions()
+    )
+  }
+
+  fun generateFunctionDefinitions(): List<FunctionDefinition> {
+    val definitions = mutableMapOf<String, FunctionDefinition>()
+    for (method in javaClass.methods) {
+      if (!Modifier.isPublic(method.modifiers)) {
+        continue
+      }
+
+      val name = method.name
+      val returnTypeName = method.returnType.name
+      val parameterNames = method.parameters.indices.map { ('a' + it).toString() }
+      val parameterTypeNames = method.parameters.map { it.type.name }
+
+      fun form(kind: String): JavaFunctionDefinition =
+        JavaFunctionDefinition(javaClass.name, kind, name, returnTypeName, parameterTypeNames)
+
+      if (Modifier.isStatic(method.modifiers)) {
+        definitions[name] = function(name, parameterNames, form("static"))
+      } else {
+        definitions[name] = function(name, parameterNames, form("virtual"))
+      }
+    }
+
+    for (field in javaClass.fields) {
+      if (!Modifier.isPublic(field.modifiers)) {
+        continue
+      }
+
+      val name = field.name
+      val valueTypeName = field.type.name
+      val isStatic = Modifier.isStatic(field.modifiers)
+      fun form(kind: String, getOrSet: Boolean): JavaFunctionDefinition =
+        JavaFunctionDefinition(javaClass.name, kind, name, valueTypeName, if (getOrSet) {
+          if (isStatic) {
+            emptyList()
+          } else {
+            listOf(javaClass.name)
+          }
+        } else {
+          if (isStatic) {
+            listOf(valueTypeName)
+          } else {
+            listOf(javaClass.name, valueTypeName)
+          }
+        })
+
+      val parametersForGetter = if (isStatic) {
+        emptyList()
+      } else {
+        listOf("object")
+      }
+
+      val parametersForSetter = if (isStatic) {
+        listOf("value")
+      } else {
+        listOf("object", "value")
+      }
+
+      val getterKind = if (isStatic) "static-getter" else "getter"
+      val setterKind = if (isStatic) "static-setter" else "setter"
+      definitions[name + "_get"] = function(name + "_get", parametersForGetter, form(getterKind, true))
+      definitions[name + "_set"] = function(name + "_set", parametersForSetter, form(setterKind, false))
+    }
+
+    return definitions.values.toList()
+  }
+
+  private fun function(name: String, parameterNames: List<String>, functionDefinition: JavaFunctionDefinition): FunctionDefinition =
+    FunctionDefinition(
+      modifiers = DefinitionModifiers(true),
+      symbol = Symbol("${prefix}_${name}"),
+      arguments = parameterNames.map { Symbol(it) },
+      native = asNative(functionDefinition),
+      block = null
+    )
+
+  private fun asNative(functionDefinition: JavaFunctionDefinition): Native =
+    Native(Symbol("java"), StringLiteral(functionDefinition.encode()))
+}

ffi/src/main/kotlin/gay/pizza/pork/ffi/JavaAutogenContentSource.kt

@@ -0,0 +1,19 @@
+package gay.pizza.pork.ffi
+
+import gay.pizza.pork.ast.visit
+import gay.pizza.pork.frontend.ContentSource
+import gay.pizza.pork.parser.CharSource
+import gay.pizza.pork.parser.Printer
+import gay.pizza.pork.parser.StringCharSource
+
+object JavaAutogenContentSource : ContentSource {
+  override fun loadAsCharSource(path: String): CharSource {
+    val javaClassName = path.replace("/", ".").substring(0, path.length - 5)
+    val autogen = JavaAutogen(Class.forName(javaClassName))
+    val compilationUnit = autogen.generateCompilationUnit()
+    val content = buildString { Printer(this).visit(compilationUnit) }
+    return StringCharSource(content)
+  }
+
+  override fun stableContentIdentity(path: String): String = path
+}

ffi/src/main/kotlin/gay/pizza/pork/ffi/JavaFunctionDefinition.kt

@@ -20,4 +20,12 @@ class JavaFunctionDefinition(
       return JavaFunctionDefinition(type, kind, symbol, returnType, parameters)
     }
   }
+
+  fun encode(): String = buildString {
+    append("${type}:${kind}:${symbol}:${returnType}")
+    if (parameters.isNotEmpty()) {
+      append(":")
+      append(parameters.joinToString(","))
+    }
+  }
 }