From 14ec85881d16eb6e41cf3abff2f05d11763a5eea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B1=85=E6=88=8E=E6=B0=8F?= <kionjungz@gmail.com>
Date: Wed, 6 Sep 2017 23:45:09 +0800
Subject: [PATCH] feat(config): references to optional config resources, ending
 with "?"

---
 data/test/config_compiler_test.yaml |  8 ++++++++
 src/rime/config/config_compiler.cc  | 26 +++++++++++++++++---------
 src/rime/config/config_compiler.h   |  1 +
 test/config_compiler_test.cc        |  9 ++++++++-
 4 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/data/test/config_compiler_test.yaml b/data/test/config_compiler_test.yaml
index 408f67224..d28fe029c 100644
--- a/data/test/config_compiler_test.yaml
+++ b/data/test/config_compiler_test.yaml
@@ -52,6 +52,14 @@ dependency_priorities:
       player: bisu
     __include: /starcraft/protoss
 
+optional_reference:
+  __include: nonexistent.yaml:/?
+  __patch:
+    - local/nonexistent_patch?
+    - config_test:/nonexistent_patch?
+    - nonexistent:/patch?
+  untouched: true
+
 local:
   patch:
     battlefields/@next: match point
diff --git a/src/rime/config/config_compiler.cc b/src/rime/config/config_compiler.cc
index 7da6df19d..7dce33783 100644
--- a/src/rime/config/config_compiler.cc
+++ b/src/rime/config/config_compiler.cc
@@ -46,7 +46,7 @@ struct PendingChild : Dependency {
 };
 
 string Reference::repr() const {
-  return resource_id + ":" + local_path;
+  return resource_id + ":" + local_path + (optional ? " <optional>" : "");
 }
 
 template <class StreamT>
@@ -131,7 +131,7 @@ bool IncludeReference::Resolve(ConfigCompiler* compiler) {
   DLOG(INFO) << "IncludeReference::Resolve(reference = " << reference << ")";
   auto item = ResolveReference(compiler, reference);
   if (!item) {
-    return false;
+    return reference.optional;
   }
   *target = item;
   return true;
@@ -141,7 +141,7 @@ bool PatchReference::Resolve(ConfigCompiler* compiler) {
   DLOG(INFO) << "PatchReference::Resolve(reference = " << reference << ")";
   auto item = ResolveReference(compiler, reference);
   if (!item) {
-    return false;
+    return reference.optional;
   }
   if (!Is<ConfigMap>(item)) {
     LOG(ERROR) << "invalid patch at " << reference;
@@ -227,14 +227,18 @@ ConfigCompiler::~ConfigCompiler() {
 }
 
 Reference ConfigCompiler::CreateReference(const string& qualified_path) {
+  auto end = qualified_path.find_last_of("?");
+  bool optional = end != string::npos;
   auto separator = qualified_path.find_first_of(":");
   string resource_id = resource_resolver_->ToResourceId(
       (separator == string::npos || separator == 0) ?
-      graph_->current_resource_id() : qualified_path.substr(0, separator));
+      graph_->current_resource_id() :
+      qualified_path.substr(0, separator));
   string local_path = (separator == string::npos) ?
-      qualified_path :
-      qualified_path.substr(separator + 1);
-  return Reference{resource_id, local_path};
+      qualified_path.substr(0, end) :
+      qualified_path.substr(separator + 1,
+                            optional ? end - separator - 1 : end);
+  return Reference{resource_id, local_path, optional};
 }
 
 void ConfigCompiler::AddDependency(an<Dependency> dependency) {
@@ -354,10 +358,14 @@ static an<ConfigItem> ResolveReference(ConfigCompiler* compiler,
                                        const Reference& reference) {
   auto resource = compiler->GetCompiledResource(reference.resource_id);
   if (!resource) {
-    LOG(INFO) << "resource not loaded, compiling: " << reference.resource_id;
+    DLOG(INFO) << "resource not loaded, compiling: " << reference.resource_id;
     resource = compiler->Compile(reference.resource_id);
     if (!resource->loaded) {
-      LOG(ERROR) << "resource could not be loaded: " << reference.resource_id;
+      if (reference.optional) {
+        LOG(INFO) << "optional resource not loaded: " << reference.resource_id;
+      } else {
+        LOG(ERROR) << "resource could not be loaded: " << reference.resource_id;
+      }
       return nullptr;
     }
   }
diff --git a/src/rime/config/config_compiler.h b/src/rime/config/config_compiler.h
index 9e92ea296..efeb0fe9e 100644
--- a/src/rime/config/config_compiler.h
+++ b/src/rime/config/config_compiler.h
@@ -30,6 +30,7 @@ struct ConfigResource : ConfigItemRef {
 struct Reference {
   string resource_id;
   string local_path;
+  bool optional;
 
   string repr() const;
 };
diff --git a/test/config_compiler_test.cc b/test/config_compiler_test.cc
index 69990ddbd..533d53b1b 100644
--- a/test/config_compiler_test.cc
+++ b/test/config_compiler_test.cc
@@ -129,4 +129,11 @@ TEST_F(RimeConfigCompilerTest, DependencyPriorities) {
   EXPECT_EQ("bisu", player);
 }
 
-// TODO: test failure cases
+TEST_F(RimeConfigCompilerTest, OptionalReference) {
+  const string& prefix = "optional_reference/";
+  EXPECT_TRUE(config_->IsNull(prefix + "__include"));
+  EXPECT_TRUE(config_->IsNull(prefix + "__patch"));
+  bool untouched;
+  EXPECT_TRUE(config_->GetBool(prefix + "untouched", &untouched));
+  EXPECT_TRUE(untouched);
+}