Add utility code for really nice command-line option parsing and start using it…

Add utility code for really nice command-line option parsing and start using it in the compiler (still WIP).

c++/Makefile.am

@@ -110,8 +110,10 @@ includekj_HEADERS =                                            \
   src/kj/arena.h                                               \
   src/kj/io.h                                                  \
   src/kj/tuple.h                                               \
+  src/kj/function.h                                            \
   src/kj/mutex.h                                               \
-  src/kj/thread.h
+  src/kj/thread.h                                              \
+  src/kj/main.h
 
 includekjparse_HEADERS =                                       \
   src/kj/parse/common.h                                        \
@@ -150,6 +152,7 @@ libcapnp_la_SOURCES=                                           \
   src/kj/io.c++                                                \
   src/kj/mutex.c++                                             \
   src/kj/thread.c++                                            \
+  src/kj/main.c++                                              \
   src/kj/parse/char.c++                                        \
   src/capnp/blob.c++                                           \
   src/capnp/arena.h                                            \
@@ -199,6 +202,7 @@ capnp_test_SOURCES =                                           \
   src/kj/arena-test.c++                                        \
   src/kj/units-test.c++                                        \
   src/kj/tuple-test.c++                                        \
+  src/kj/function-test.c++                                     \
   src/kj/mutex-test.c++                                        \
   src/kj/parse/common-test.c++                                 \
   src/kj/parse/char-test.c++                                   \

c++/src/capnp/compiler/capnpc2.c++

@@ -24,6 +24,7 @@
 #include "lexer.h"
 #include "parser.h"
 #include "compiler.h"
+#include "module-loader.h"
 #include <capnp/pretty-print.h>
 #include <kj/vector.h>
 #include <kj/io.h>
@@ -31,6 +32,10 @@
 #include <kj/debug.h>
 #include "../message.h"
 #include <iostream>
+#include <kj/main.h>
+
+namespace capnp {
+namespace compiler {
 
 class DummyModule: public capnp::compiler::Module {
 public:
@@ -53,6 +58,36 @@ public:
   }
 };
 
+class CompilerMain {
+public:
+  explicit CompilerMain(kj::ProcessContext& context)
+      : context(context), loader(STDERR_FILENO) {}
+
+  kj::MainFunc getMain() {
+    return kj::MainBuilder(
+          context, "Cap'n Proto compiler version 0.2",
+          "Compiles Cap'n Proto schema files and generates corresponding source code in one or "
+          "more languages.")
+        .expectOneOrMoreArgs("source", KJ_BIND_METHOD(*this, addSource))
+        .build();
+  }
+
+  kj::MainBuilder::Validity addSource(kj::StringPtr file) {
+    KJ_IF_MAYBE(module, loader.loadModule(file, file)) {
+      compiler.add(*module, Compiler::EAGER);
+    } else {
+      return "no such file";
+    }
+
+    return true;
+  }
+
+private:
+  kj::ProcessContext& context;
+  ModuleLoader loader;
+  Compiler compiler;
+};
+
 int main(int argc, char* argv[]) {
   // Eventually this will be capnpc.  For now it's just a dummy program that tests parsing.
 
@@ -109,3 +144,8 @@ int main(int argc, char* argv[]) {
 
   return 0;
 }
+
+}  // namespace compiler
+}  // namespace capnp
+
+KJ_MAIN(capnp::compiler::CompilerMain);

c++/src/capnp/compiler/compiler.c++

@@ -81,7 +81,7 @@ public:
   kj::Maybe<const Node&> lookup(const DeclName::Reader& name) const;
   // Resolve an arbitrary DeclName to a Node.
 
-  kj::Maybe<Schema> getBootstrapOrFinalSchema() const;
+  kj::Maybe<Schema> getBootstrapSchema() const;
   kj::Maybe<Schema> getFinalSchema() const;
 
   void traverse(Compiler::Mode mode) const;
@@ -93,7 +93,7 @@ public:
 
   // implements NodeTranslator::Resolver -----------------------------
   kj::Maybe<ResolvedName> resolve(const DeclName::Reader& name) const override;
-  kj::Maybe<Schema> resolveMaybeBootstrapSchema(uint64_t id) const override;
+  kj::Maybe<Schema> resolveBootstrapSchema(uint64_t id) const override;
   kj::Maybe<Schema> resolveFinalSchema(uint64_t id) const override;
 
 private:
@@ -212,7 +212,7 @@ public:
   Impl();
   virtual ~Impl();
 
-  uint64_t add(Module& module, Mode mode) const;
+  uint64_t add(const Module& module, Mode mode) const;
   const CompiledModule& add(const Module& parsedModule) const;
 
   struct Workspace {
@@ -473,8 +473,8 @@ const Compiler::Node::Content& Compiler::Node::getContent(Content::State minimum
             locked->translator->getBootstrapNode());
       })) {
         locked->bootstrapSchema = nullptr;
-        addError(kj::str("Internal compiler bug: Bootstrap schema failed validation: ",
-                         exception->getDescription()));
+        addError(kj::str("Internal compiler bug: Bootstrap schema failed validation:\n",
+                         *exception));
       }
 
       // If the Workspace is destroyed while this Node is still in the BOOTSTRAP state,
@@ -500,8 +500,8 @@ const Compiler::Node::Content& Compiler::Node::getContent(Content::State minimum
             locked->translator->finish());
       })) {
         locked->finalSchema = nullptr;
-        addError(kj::str("Internal compiler bug: Schema failed validation: ",
-                         exception->getDescription()));
+        addError(kj::str("Internal compiler bug: Schema failed validation:\n",
+                         *exception));
       }
 
       locked->advanceState(Content::FINISHED);
@@ -605,12 +605,19 @@ kj::Maybe<const Compiler::Node&> Compiler::Node::lookup(const DeclName::Reader&
   return *node;
 }
 
-kj::Maybe<Schema> Compiler::Node::getBootstrapOrFinalSchema() const {
+kj::Maybe<Schema> Compiler::Node::getBootstrapSchema() const {
   auto& content = getContent(Content::BOOTSTRAP);
 
   if (__atomic_load_n(&content.state, __ATOMIC_ACQUIRE) == Content::FINISHED &&
-      content.finalSchema != nullptr) {
-    return content.finalSchema;
+      content.bootstrapSchema == nullptr) {
+    // The bootstrap schema was discarded.  Copy it from the final schema.
+    // (We can't just return the final schema because using it could trigger schema loader
+    // callbacks that would deadlock.)
+    KJ_IF_MAYBE(finalSchema, content.finalSchema) {
+      return module->getCompiler().getWorkspace().bootstrapLoader.loadOnce(finalSchema->getProto());
+    } else {
+      return nullptr;
+    }
   } else {
     return content.bootstrapSchema;
   }
@@ -640,9 +647,9 @@ kj::Maybe<NodeTranslator::Resolver::ResolvedName> Compiler::Node::resolve(
   });
 }
 
-kj::Maybe<Schema> Compiler::Node::resolveMaybeBootstrapSchema(uint64_t id) const {
+kj::Maybe<Schema> Compiler::Node::resolveBootstrapSchema(uint64_t id) const {
   KJ_IF_MAYBE(node, module->getCompiler().findNode(id)) {
-    return node->getBootstrapOrFinalSchema();
+    return node->getBootstrapSchema();
   } else {
     KJ_FAIL_REQUIRE("Tried to get schema for ID we haven't seen before.");
   }
@@ -743,7 +750,7 @@ kj::Maybe<const Compiler::Node&> Compiler::Impl::lookupBuiltin(kj::StringPtr nam
   }
 }
 
-uint64_t Compiler::Impl::add(Module& module, Mode mode) const {
+uint64_t Compiler::Impl::add(const Module& module, Mode mode) const {
   Impl::Workspace workspace;
   auto lock = this->workspace.lockExclusive();
   *lock = &workspace;
@@ -766,7 +773,7 @@ void Compiler::Impl::load(const SchemaLoader& loader, uint64_t id) const {
       node->getFinalSchema();
     } else {
       // Must be the bootstrap loader.
-      node->getBootstrapOrFinalSchema();
+      node->getBootstrapSchema();
     }
   }
 }
@@ -776,7 +783,7 @@ void Compiler::Impl::load(const SchemaLoader& loader, uint64_t id) const {
 Compiler::Compiler(): impl(kj::heap<Impl>()) {}
 Compiler::~Compiler() {}
 
-uint64_t Compiler::add(Module& module, Mode mode) const {
+uint64_t Compiler::add(const Module& module, Mode mode) const {
   return impl->add(module, mode);
 }
 

c++/src/capnp/compiler/compiler.h

@@ -76,7 +76,7 @@ public:
     // use EAGER mode.
   };
 
-  uint64_t add(Module& module, Mode mode) const;
+  uint64_t add(const Module& module, Mode mode) const;
   // Add a module to the Compiler, returning the module's file ID.  The ID can then be used to
   // look up the schema in the SchemaLoader returned by `getLoader()`.  However, if there were any
   // errors while compiling (reported via `module.addError()`), then the SchemaLoader may behave as

c++/src/capnp/compiler/module-loader.c++

@@ -263,7 +263,7 @@ public:
     uint startLine = findLargestElementBefore(lines, startByte);
     uint startCol = startByte - lines[startLine];
     loader.writeError(
-        kj::str(localName, ":", startLine, ":", startCol, ": error: ", message, "\n"));
+        kj::str(localName, ":", startLine + 1, ":", startCol + 1, ": error: ", message, "\n"));
   }
 
 private:
@@ -291,7 +291,7 @@ kj::Maybe<const Module&> ModuleLoader::Impl::loadModule(
     return *iter->second;
   }
 
-  if (access(canonicalLocalName.cStr(), R_OK) < 0) {
+  if (access(canonicalLocalName.cStr(), F_OK) < 0) {
     // No such file.
     return nullptr;
   }

c++/src/capnp/compiler/node-translator.c++

@@ -1489,8 +1489,7 @@ void NodeTranslator::compileValue(ValueExpression::Reader source, schema::Type::
       }
       break;
     case schema::Type::Body::STRUCT_TYPE:
-      KJ_IF_MAYBE(structSchema, resolver.resolveMaybeBootstrapSchema(
-          type.getBody().getStructType())) {
+      KJ_IF_MAYBE(structSchema, resolver.resolveBootstrapSchema(type.getBody().getStructType())) {
         DynamicSlot slot(valueUnion, member, structSchema->asStruct());
         compileValue(source, slot, isBootstrap);
       }
@@ -1527,7 +1526,7 @@ void NodeTranslator::compileValueInner(
         kj::StringPtr id = name.getBase().getRelativeName().getValue();
 
         KJ_IF_MAYBE(enumId, dst.getEnumType()) {
-          KJ_IF_MAYBE(enumSchema, resolver.resolveMaybeBootstrapSchema(*enumId)) {
+          KJ_IF_MAYBE(enumSchema, resolver.resolveBootstrapSchema(*enumId)) {
             KJ_IF_MAYBE(enumerant, enumSchema->asEnum().findEnumerantByName(id)) {
               dst.set(DynamicEnum(*enumerant));
               wasSet = true;
@@ -1677,7 +1676,7 @@ kj::Maybe<DynamicValue::Reader> NodeTranslator::readConstant(
     // We need to be very careful not to query this Schema's dependencies because if it is
     // a final schema then this query could trigger a lazy load which would deadlock.
     kj::Maybe<Schema> maybeConstSchema = isBootstrap ?
-        resolver.resolveMaybeBootstrapSchema(resolved->id) :
+        resolver.resolveBootstrapSchema(resolved->id) :
         resolver.resolveFinalSchema(resolved->id);
     KJ_IF_MAYBE(constSchema, maybeConstSchema) {
       auto constReader = constSchema->getProto().getBody().getConstNode();
@@ -1689,7 +1688,7 @@ kj::Maybe<DynamicValue::Reader> NodeTranslator::readConstant(
         auto constType = constReader.getType();
         switch (constType.getBody().which()) {
           case schema::Type::Body::STRUCT_TYPE:
-            KJ_IF_MAYBE(structSchema, resolver.resolveMaybeBootstrapSchema(
+            KJ_IF_MAYBE(structSchema, resolver.resolveBootstrapSchema(
                 constType.getBody().getStructType())) {
               constValue = objValue.as(structSchema->asStruct());
             } else {
@@ -1719,7 +1718,7 @@ kj::Maybe<DynamicValue::Reader> NodeTranslator::readConstant(
         // A fully unqualified identifier looks like it might refer to a constant visible in the
         // current scope, but if that's really what the user wanted, we want them to use a
         // qualified name to make it more obvious.  Report an error.
-        KJ_IF_MAYBE(scope, resolver.resolveMaybeBootstrapSchema(
+        KJ_IF_MAYBE(scope, resolver.resolveBootstrapSchema(
             constSchema->getProto().getScopeId())) {
           auto scopeReader = scope->getProto();
           kj::StringPtr parent;
@@ -1752,19 +1751,19 @@ kj::Maybe<ListSchema> NodeTranslator::makeListSchemaOf(schema::Type::Reader elem
   auto body = elementType.getBody();
   switch (body.which()) {
     case schema::Type::Body::ENUM_TYPE:
-      KJ_IF_MAYBE(enumSchema, resolver.resolveMaybeBootstrapSchema(body.getEnumType())) {
+      KJ_IF_MAYBE(enumSchema, resolver.resolveBootstrapSchema(body.getEnumType())) {
         return ListSchema::of(enumSchema->asEnum());
       } else {
         return nullptr;
       }
     case schema::Type::Body::STRUCT_TYPE:
-      KJ_IF_MAYBE(structSchema, resolver.resolveMaybeBootstrapSchema(body.getStructType())) {
+      KJ_IF_MAYBE(structSchema, resolver.resolveBootstrapSchema(body.getStructType())) {
         return ListSchema::of(structSchema->asStruct());
       } else {
         return nullptr;
       }
     case schema::Type::Body::INTERFACE_TYPE:
-      KJ_IF_MAYBE(interfaceSchema, resolver.resolveMaybeBootstrapSchema(body.getInterfaceType())) {
+      KJ_IF_MAYBE(interfaceSchema, resolver.resolveBootstrapSchema(body.getInterfaceType())) {
         return ListSchema::of(interfaceSchema->asInterface());
       } else {
         return nullptr;
@@ -1806,7 +1805,7 @@ Orphan<List<schema::Annotation>> NodeTranslator::compileAnnotationApplications(
             "'", declNameString(name), "' is not an annotation."));
       } else {
         annotationBuilder.setId(decl->id);
-        KJ_IF_MAYBE(annotationSchema, resolver.resolveMaybeBootstrapSchema(decl->id)) {
+        KJ_IF_MAYBE(annotationSchema, resolver.resolveBootstrapSchema(decl->id)) {
           auto node = annotationSchema->getProto().getBody().getAnnotationNode();
           if (!toDynamic(node).get(targetsFlagName).as<bool>()) {
             errorReporter.addErrorOn(name, kj::str(

c++/src/capnp/compiler/node-translator.h

@@ -54,17 +54,24 @@ public:
     // Look up the given name, relative to this node, and return basic information about the
     // target.
 
-    virtual kj::Maybe<Schema> resolveMaybeBootstrapSchema(uint64_t id) const = 0;
-    // Get the schema for the given ID.  Returning either a bootstrap schema or a final schema
-    // is acceptable.  Throws an exception if the id is not one that was found by calling resolve()
-    // or by traversing other schemas.  Returns null if the ID is recognized, but the corresponding
+    virtual kj::Maybe<Schema> resolveBootstrapSchema(uint64_t id) const = 0;
+    // Get the schema for the given ID.  If a schema is returned, it must be safe to traverse its
+    // dependencies using Schema::getDependency().  A schema that is only at the bootstrap stage
+    // is acceptable.
+    //
+    // Throws an exception if the id is not one that was found by calling resolve() or by
+    // traversing other schemas.  Returns null if the ID is recognized, but the corresponding
     // schema node failed to be built for reasons that were already reported.
 
     virtual kj::Maybe<Schema> resolveFinalSchema(uint64_t id) const = 0;
-    // Get the final schema for the given ID.  A bootstrap schema is not acceptable.  Throws an
-    // exception if the id is not one that was found by calling resolve() or by traversing other
-    // schemas.  Returns null if the ID is recognized, but the corresponding schema node failed to
-    // be built for reasons that were already reported.
+    // Get the final schema for the given ID.  A bootstrap schema is not acceptable.  It is NOT
+    // safe to traverse the schema's dependencies with Schema::getDependency() as doing so may
+    // trigger lazy loading callbacks that deadlock on the compiler mutex.  Instead, the caller
+    // should carefully look up dependencies through this Resolver.
+    //
+    // Throws an exception if the id is not one that was found by calling resolve() or by
+    // traversing other schemas.  Returns null if the ID is recognized, but the corresponding
+    // schema node failed to be built for reasons that were already reported.
   };
 
   NodeTranslator(const Resolver& resolver, const ErrorReporter& errorReporter,

c++/src/capnp/compiler/parser.c++

@@ -583,11 +583,23 @@ CapnpParser::CapnpParser(Orphanage orphanageParam, const ErrorReporter& errorRep
   // -----------------------------------------------------------------
 
   parsers.usingDecl = arena.copy(p::transform(
-      p::sequence(keyword("using"), identifier, op("="), parsers.declName),
-      [this](Located<Text::Reader>&& name, Orphan<DeclName>&& target) -> DeclParserResult {
+      p::sequence(keyword("using"), p::optional(p::sequence(identifier, op("="))),
+                  parsers.declName),
+      [this](kj::Maybe<Located<Text::Reader>>&& name, Orphan<DeclName>&& target)
+          -> DeclParserResult {
         auto decl = orphanage.newOrphan<Declaration>();
         auto builder = decl.get();
-        name.copyTo(builder.initName());
+        KJ_IF_MAYBE(n, name) {
+          n->copyTo(builder.initName());
+        } else {
+          auto targetPath = target.getReader().getMemberPath();
+          if (targetPath.size() == 0) {
+            errorReporter.addErrorOn(
+                target.getReader(), "'using' declaration without '=' must use a qualified path.");
+          } else {
+            builder.setName(targetPath[targetPath.size() - 1]);
+          }
+        }
         // no id, no annotations for using decl
         builder.getBody().initUsingDecl().adoptTarget(kj::mv(target));
         return DeclParserResult(kj::mv(decl));

c++/src/kj/array.c++

@@ -54,6 +54,12 @@ void DestructorOnlyArrayDisposer::disposeImpl(
   }
 }
 
+const NullArrayDisposer NullArrayDisposer::instance = NullArrayDisposer();
+
+void NullArrayDisposer::disposeImpl(
+    void* firstElement, size_t elementSize, size_t elementCount,
+    size_t capacity, void (*destroyElement)(void*)) const {}
+
 namespace _ {  // private
 
 void* HeapArrayDisposer::allocateImpl(size_t elementSize, size_t elementCount, size_t capacity,

c++/src/kj/array.h

@@ -108,6 +108,17 @@ public:
                    size_t capacity, void (*destroyElement)(void*)) const override;
 };
 
+class NullArrayDisposer: public ArrayDisposer {
+  // An ArrayDisposer that does nothing.  Can be used to construct a fake Arrays that doesn't
+  // actually own its content.
+
+public:
+  static const NullArrayDisposer instance;
+
+  void disposeImpl(void* firstElement, size_t elementSize, size_t elementCount,
+                   size_t capacity, void (*destroyElement)(void*)) const override;
+};
+
 // =======================================================================================
 // Array
 

c++/src/kj/function-test.c++

+// Copyright (c) 2013, Kenton Varda <temporal@gmail.com>
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+//    list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//    this list of conditions and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "function.h"
+#include <gtest/gtest.h>
+
+namespace kj {
+namespace {
+
+TEST(Function, Lambda) {
+  int i = 0;
+
+  Function<int(int, int)> f = [&](int a, int b) { return a + b + i++; };
+
+  EXPECT_EQ(123 + 456, f(123, 456));
+  EXPECT_EQ(7 + 8 + 1, f(7, 8));
+  EXPECT_EQ(9 + 2 + 2, f(2, 9));
+
+  EXPECT_EQ(i, 3);
+}
+
+struct TestType {
+  int callCount;
+
+  TestType(int callCount = 0): callCount(callCount) {}
+
+  ~TestType() { callCount = 1234; }
+  // Make sure we catch invalid post-destruction uses.
+
+  int foo(int a, int b) {
+    return a + b + callCount++;
+  }
+};
+
+TEST(Function, Method) {
+  TestType obj;
+  Function<int(int, int)> f = KJ_BIND_METHOD(obj, foo);
+  Function<uint(uint, uint)> f2 = KJ_BIND_METHOD(obj, foo);
+
+  EXPECT_EQ(123 + 456, f(123, 456));
+  EXPECT_EQ(7 + 8 + 1, f(7, 8));
+  EXPECT_EQ(9 + 2 + 2, f2(2, 9));
+
+  EXPECT_EQ(3, obj.callCount);
+
+  // Bind to a temporary.
+  f = KJ_BIND_METHOD(TestType(10), foo);
+
+  EXPECT_EQ(123 + 456 + 10, f(123, 456));
+  EXPECT_EQ(7 + 8 + 11, f(7, 8));
+  EXPECT_EQ(9 + 2 + 12, f(2, 9));
+
+  // Bind to a move.
+  f = KJ_BIND_METHOD(kj::mv(obj), foo);
+  obj.callCount = 1234;
+
+  EXPECT_EQ(123 + 456 + 3, f(123, 456));
+  EXPECT_EQ(7 + 8 + 4, f(7, 8));
+  EXPECT_EQ(9 + 2 + 5, f(2, 9));
+}
+
+} // namespace
+} // namespace kj

c++/src/kj/function.h

+// Copyright (c) 2013, Kenton Varda <temporal@gmail.com>
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+//    list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//    this list of conditions and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef KJ_FUNCTION_H_
+#define KJ_FUNCTION_H_
+
+#include "memory.h"
+
+namespace kj {
+
+template <typename Signature>
+class Function;
+// Function wrapper using virtual-based polymorphism.  Use this when template polymorphism is
+// not possible.  You can, for example, accept a Function as a parameter:
+//
+//     void setFilter(Function<bool(const Widget&)> filter);
+//
+// The caller of `setFilter()` may then pass any callable object as the parameter.  The callable
+// object does not have to have the exact signature specified, just one that is "compatible" --
+// i.e. the return type is covariant and the parameters are contravariant.
+//
+// Unlike `std::function`, `kj::Function`s are movable but not copyable, just like `kj::Own`.  This
+// is to avoid unexpected heap allocation or slow atomic reference counting.
+//
+// When a `Function` is constructed from an lvalue, it captures only a reference to the value.
+// When constructed from an rvalue, it invokes the value's move constructor.  So, for example:
+//
+//     struct AddN {
+//       int n;
+//       int operator(int i) { return i + n; }
+//     }
+//
+//     Function<int(int, int)> f1 = AddN{2};
+//     // f1 owns an instance of AddN.  It may safely be moved out
+//     // of the local scope.
+//
+//     AddN adder(2);
+//     Function<int(int, int)> f2 = adder;
+//     // f2 contains a reference to `adder`.  Thus, it becomes invalid
+//     // when `adder` goes out-of-scope.
+//
+//     AddN adder2(2);
+//     Function<int(int, int)> f3 = kj::mv(adder2);
+//     // f3 owns an insatnce of AddN moved from `adder2`.  f3 may safely
+//     // be moved out of the local scope.
+//
+// Additionally, a Function may be bound to a class method using KJ_BIND_METHOD(object, methodName).
+// For example:
+//
+//     class Printer {
+//     public:
+//       void print(int i);
+//       void print(kj::StringPtr s);
+//     };
+//
+//     Printer p;
+//
+//     Function<void(uint)> intPrinter = KJ_BIND_METHOD(p, print);
+//     // Will call Printer::print(int).
+//
+//     Function<void(const char*)> strPrinter = KJ_BIND_METHOD(p, print);
+//     // Will call Printer::print(kj::StringPtr).
+//
+// Notice how KJ_BIND_METHOD is able to figure out which overload to use depending on the kind of
+// Function it is binding to.
+
+template <typename Return, typename... Params>
+class Function<Return(Params...)> {
+public:
+  template <typename F>
+  inline Function(F&& f): impl(heap<Impl<F>>(kj::fwd<F>(f))) {}
+  Function() = default;
+
+  inline Return operator()(Params... params) {
+    return (*impl)(kj::fwd<Params>(params)...);
+  }
+
+private:
+  class Iface {
+  public:
+    virtual Return operator()(Params... params) = 0;
+  };
+
+  template <typename F>
+  class Impl final: public Iface {
+  public:
+    explicit Impl(F&& f): f(kj::fwd<F>(f)) {}
+
+    Return operator()(Params... params) override {
+      return f(kj::fwd<Params>(params)...);
+    }
+
+  private:
+    F f;
+  };
+
+  Own<Iface> impl;
+};
+
+namespace _ {
+
+template <typename T>
+T rvalueOrRef(T&&);
+// Hack to help detect if an expression is an lvalue or an rvalue.
+//
+//     int i;
+//     decltype(i) i1(i);                              // i1 has type int.
+//     decltype(rvalueOrRef(i)) i2(i);                 // i2 has type int&.
+//     decltype(rvalueOrRef(kj::mv(i)) i3(kj::mv(i));  // i3 has type int.
+
+}  // namespace _
+
+#define KJ_BIND_METHOD(obj, method) \
+  ({ \
+    typedef decltype(::kj::_::rvalueOrRef(obj)) T; \
+    class F { \
+    public: \
+      inline F(T&& t): t(::kj::fwd<T>(t)) {} \
+      template <typename... Params> \
+      auto operator()(Params&&... params) \
+          -> decltype(::kj::instance<T>().method(::kj::fwd<Params>(params)...)) { \
+        return t.method(::kj::fwd<Params>(params)...); \
+      } \
+    private: \
+      T t; \
+    }; \
+    (F(obj)); \
+  })
+// Macro that produces a functor object which forwards to the method `obj.name`.  If `obj` is an
+// lvalue, the functor will hold a reference to it.  If `obj` is an rvalue, the functor will
+// contain a copy (by move) of it.
+
+}  // namespace kj
+
+#endif  // KJ_FUNCTION_H_

c++/src/kj/string.h

@@ -84,6 +84,8 @@ public:
   inline bool startsWith(const StringPtr& other) const;
   inline bool endsWith(const StringPtr& other) const;
 
+  inline Maybe<size_t> findFirst(char c) const;
+
 private:
   inline StringPtr(ArrayPtr<const char> content): content(content) {}
 
@@ -109,6 +111,8 @@ public:
   inline String(decltype(nullptr)): content(nullptr) {}
   inline String(char* value, size_t size, const ArrayDisposer& disposer);
   // Does not copy.  `size` does not include NUL terminator, but `value` must be NUL-terminated.
+  inline explicit String(Array<char> buffer);
+  // Does not copy.  Requires `buffer` ends with `\0`.
 
   inline operator ArrayPtr<char>();
   inline operator ArrayPtr<const char>() const;
@@ -373,6 +377,15 @@ inline bool StringPtr::endsWith(const StringPtr& other) const {
       memcmp(end() - other.size(), other.content.begin(), other.size()) == 0;
 }
 
+inline Maybe<size_t> StringPtr::findFirst(char c) const {
+  const char* pos = reinterpret_cast<const char*>(memchr(content.begin(), c, size()));
+  if (pos == nullptr) {
+    return nullptr;
+  } else {
+    return pos - content.begin();
+  }
+}
+
 inline String::operator ArrayPtr<char>() {
   return content == nullptr ? ArrayPtr<char>(nullptr) : content.slice(0, content.size() - 1);
 }
@@ -404,6 +417,10 @@ inline String::String(char* value, size_t size, const ArrayDisposer& disposer)
   KJ_IREQUIRE(value[size] == '\0', "String must be NUL-terminated.");
 }
 
+inline String::String(Array<char> buffer): content(kj::mv(buffer)) {
+  KJ_IREQUIRE(content.size() > 0 && content.back() == '\0', "String must be NUL-terminated.");
+}
+
 inline String heapString(const char* value) {
   return heapString(value, strlen(value));
 }

c++/src/kj/vector.h

@@ -82,6 +82,11 @@ public:
     builder.addAll(begin, end);
   }
 
+  template <typename Container>
+  inline void addAll(Container&& container) {
+    addAll(container.begin(), container.end());
+  }
+
 private:
   ArrayBuilder<T> builder;