Initial support for using Sonar in Swift projects (#106)

Summary:
This PR adds support for using SonarKit clients in Swift apps. Fixes #13, fixes #87

1. Swift can't import Obj-C modules which have C++ headers. For this reason, we use SonarKit as an Obj-C++ wrapper around Sonar, which is written in C++. Due to search path misconfiguration, trying to import SonarKit into a Swift project would import `xplat/Sonar/SonarPlugin.h` instead of `iOS/SonarKit/SonarPlugin.h`, which caused `file not found` errors for C++ stdlib imports like #28 because new projects don't have their search paths set up correctly.
2. The network and layout plugins have C++ definitions (struct methods, classes) in some of their headers. This causes the compiler to get confused for Swift projects, because it only supports importing Objective-C files in umbrella headers, meaning that the `SonarKit` won't build.

1. I updated the `HEADER_SEARCH_PATHS` of SonarKit.podspec's build configuration to include `${PODS_ROOT}/Headers/Private/SonarKit/**` first, which alleviates the search path issue. The Obj-C `Sample` project seems to have worked around this by including a hardcoded `${PODS_ROOT}/SonarKit/**` search path in the pbxproj, which is why Sample works but new projects (like those referenced in #28) don't. I removed this since it's no longer necessary.
2. I added a `SampleSwift` app to demonstrate using Sonar with a Swift project.
3. Because the Podfiles for `Sample` and `SampleSwift` referenced podspecs using `:podspec` instead of a concrete version, Cocoapods wouldn't copy local header files (instead, it downloads them from the source). To enable local development of these sample apps using `:path`, I added a symlink to SonarKit.podspec in the root of the directory.
4. I changed SonarKit.podspec to use a tag-based `source`, since v0.0.1 pulls from the master branch of this repo.

The layout and network plugins still don't work with Swift - in order to fix this, we'll need to work on extracting the C++ out of their headers and writing Obj-C++ wrappers for them. I decided to push this off to a later PR since this one is quite large already.

This means that we need to be able to `import SonarKit` without importing all the network/layout plugin headers. In order to make this work, I made "SonarKit/Core" the spec's `default_subspecs`.

priteshrnandgaonkar, let me know if you have any thoughts on this implementation. You can verify that the SampleSwift app works by checking out this branch, `pod install`ing in the SampleSwift directory, and building it :)

![image](https://user-images.githubusercontent.com/1168853/41928625-ac195bd8-792a-11e8-82b8-65d6233a1fbb.png)
Pull Request resolved: https://github.com/facebook/Sonar/pull/106

Reviewed By: jknoxville

Differential Revision: D8890010

Pulled By: priteshrnandgaonkar

fbshipit-source-id: 449305bcc5cbeb5787c23f51b1ecb80a5cbdad32

iOS/SonarKit.podspec

@@ -1,10 +1,10 @@
 folly_compiler_flags = '-DFB_SONARKIT_ENABLED=1 -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_HAVE_LIBGFLAGS=0 -DFOLLY_HAVE_LIBJEMALLOC=0 -DFOLLY_HAVE_PREADV=0 -DFOLLY_HAVE_PWRITEV=0 -DFOLLY_HAVE_TFO=0 -DFOLLY_USE_SYMBOLIZER=0'
 yoga_version = '~> 1.9'
 yogakit_version = '~>1.8'
-sonarkit_version = '0.6.12'
+sonarkit_version = '0.6.13'
 Pod::Spec.new do |spec|
   spec.name = 'SonarKit'
-  spec.version = '0.6.12'
+  spec.version = sonarkit_version
   spec.license = { :type => 'MIT' }
   spec.homepage = 'https://github.com/facebook/Sonar'
   spec.summary = 'Sonar iOS podspec'
@@ -14,28 +14,47 @@ Pod::Spec.new do |spec|
                   :tag=> "v"+sonarkit_version }
   spec.module_name = 'SonarKit'
   spec.platforms = { :ios => "8.4" }
+  spec.default_subspecs = "Core"
+
+  # This subspec is necessary since FBMacros.h is imported as <FBDefines/FBMacros.h>
+  # inside SKMacros.h, which is a public header file. Defining this directory as a
+  # subspec with header_dir = 'FBDefines' allows this to work, even though it wouldn't
+  # generally (you would need to import <SonarKit/FBDefines/FBMacros.h>)
+  spec.subspec 'FBDefines' do |ss|
+    ss.header_dir = 'FBDefines'
+    ss.compiler_flags = folly_compiler_flags
+    ss.source_files = 'iOS/FBDefines/**/*.h'
+    ss.public_header_files = 'iOS/FBDefines/**/*.h'
+  end
+
+  spec.subspec 'FBCxxUtils' do |ss|
+    ss.header_dir = 'FBCxxUtils'
+    ss.compiler_flags = folly_compiler_flags
+    ss.source_files = 'iOS/SonarKit/FBCxxUtils/**/*.{h,mm}'
+    # We set these files as private headers since they only need to be accessed
+    # by other SonarKit source files
+    ss.private_header_files = 'iOS/SonarKit/FBCxxUtils/**/*.h'
+  end
 
   spec.subspec "Core" do |ss|
+    ss.dependency 'SonarKit/FBDefines'
+    ss.dependency 'SonarKit/FBCxxUtils'
     ss.dependency 'Folly', '~>1.0'
     ss.dependency 'Sonar', '~>'+sonarkit_version
     ss.dependency 'CocoaAsyncSocket', '~> 7.6'
     ss.dependency 'PeerTalk', '~>0.0.2'
     ss.dependency 'OpenSSL-Static', '1.0.2.c1'
-    ss.source_files = 'iOS/FBDefines/*.{h,cpp,m,mm}', 'iOS/SonarKit/**/*.{h,cpp,m,mm}', 'iOS/SonarKit/FBCxxUtils/*.{h, mm}'
-    ss.public_header_files = 'iOS/SonarKit/CppBridge/*.{h}',
-                               'iOS/SonarKit/SonarClient.h',
-                               'iOS/SonarKit/SonarDeviceData.h',
-                               'iOS/SonarKit/SonarPlugin.h',
-                               'iOS/SonarKit/SonarResponder.h',
-                               'iOS/SonarKit/SonarConnection.h',
-                               'iOS/SonarKit/SKMacros.h'
-
-    ss.compiler_flags = '-DFB_SONARKIT_ENABLED=1 -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_HAVE_LIBGFLAGS=0 -DFOLLY_HAVE_LIBJEMALLOC=0 -DFOLLY_HAVE_PREADV=0 -DFOLLY_HAVE_PWRITEV=0 -DFOLLY_HAVE_TFO=0 -DFOLLY_USE_SYMBOLIZER=0'
+    ss.compiler_flags = folly_compiler_flags
+    ss.source_files = 'iOS/SonarKit/FBDefines/*.{h,cpp,m,mm}', 'iOS/SonarKit/CppBridge/*.{h,mm}', 'iOS/SonarKit/FBCxxUtils/*.{h,mm}', 'iOS/SonarKit/Utilities/**/*.{h,m}', 'iOS/SonarKit/*.{h,m,mm}'
+    ss.public_header_files = 'iOS/SonarKit/**/{SonarClient,SonarPlugin,SonarConnection,SonarResponder,SKMacros}.h'
+    header_search_paths = "\"$(PODS_ROOT)/SonarKit/iOS/SonarKit\" \"$(PODS_ROOT)\"/Headers/Private/SonarKit/** \"$(PODS_ROOT)/boost-for-react-native\" \"$(PODS_ROOT)/DoubleConversion\" \"$(PODS_ROOT)/PeerTalkSonar\""
     ss.pod_target_xcconfig = { "USE_HEADERMAP" => "NO",
-                               "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)\"/** \"$(PODS_ROOT)/boost-for-react-native\" \"$(PODS_ROOT)/DoubleConversion\" \"$(PODS_ROOT)/PeerTalkSonar\" \"$(PODS_ROOT)/ComponentKit\"/**" }
+                             "DEFINES_MODULE" => "YES",
+                             "HEADER_SEARCH_PATHS" => header_search_paths }
   end
 
   spec.subspec "SonarKitLayoutPlugin" do |ss|
+    ss.header_dir = "SonarKitLayoutPlugin"
     ss.dependency             'SonarKit/Core'
     ss.dependency             'Yoga', yoga_version
     ss.dependency             'YogaKit', yogakit_version
@@ -57,20 +76,23 @@ Pod::Spec.new do |spec|
   end
 
   spec.subspec "SonarKitLayoutComponentKitSupport" do |ss|
+    ss.header_dir = "SonarKitLayoutComponentKitSupport"
     ss.dependency             'SonarKit/Core'
     ss.dependency             'Yoga', yoga_version
     ss.dependency             'ComponentKit'
     ss.dependency             'SonarKit/SonarKitLayoutPlugin'
     ss.compiler_flags       = folly_compiler_flags
+    ss.dependency             'SonarKit/SonarKitLayoutPlugin'
     ss.public_header_files = 'iOS/Plugins/SonarKitLayoutPlugin/SonarKitLayoutComponentKitSupport/SonarKitLayoutComponentKitSupport.h',
                              'iOS/Plugins/SonarKitLayoutPlugin/SonarKitLayoutComponentKitSupport/SKComponentLayoutWrapper.h'
 
     ss.source_files         = "iOS/Plugins/SonarKitLayoutPlugin/SonarKitLayoutComponentKitSupport/**/*.{h,cpp,m,mm}"
     ss.pod_target_xcconfig = { "USE_HEADERMAP" => "NO",
-                                 "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)\"" }
+                                "HEADER_SEARCH_PATHS" => "\"$(PODS_ROOT)\"/Headers/Private/SonarKit/**" }
   end
 
   spec.subspec "SonarKitNetworkPlugin" do |ss|
+    ss.header_dir = "SonarKitNetworkPlugin"
     ss.dependency             'SonarKit/Core'
     ss.compiler_flags       = folly_compiler_flags
     ss.public_header_files = 'iOS/Plugins/SonarKitNetworkPlugin/SonarKitNetworkPlugin/SonarKitNetworkPlugin.h',
@@ -79,16 +101,17 @@ Pod::Spec.new do |spec|
                              'iOS/Plugins/SonarKitNetworkPlugin/SonarKitNetworkPlugin/SKNetworkReporter.h'
     ss.source_files         = "iOS/Plugins/SonarKitNetworkPlugin/SonarKitNetworkPlugin/*.{h,cpp,m,mm}"
     ss.pod_target_xcconfig = { "USE_HEADERMAP" => "NO",
-                                 "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)\"" }
+                                "HEADER_SEARCH_PATHS" => "\"$(PODS_ROOT)\"/Headers/Private/SonarKit/**" }
   end
 
   spec.subspec "SKIOSNetworkPlugin" do |ss|
-    ss.dependency             'SonarKit/Core'
-    ss.dependency  'SonarKit/SonarKitNetworkPlugin'
+    ss.header_dir = "SKIOSNetworkPlugin"
+    ss.dependency 'SonarKit/Core'
+    ss.dependency 'SonarKit/SonarKitNetworkPlugin'
     ss.compiler_flags       = folly_compiler_flags
     ss.public_header_files = 'iOS/Plugins/SonarKitNetworkPlugin/SKIOSNetworkPlugin/SKIOSNetworkAdapter.h'
     ss.source_files         = "iOS/Plugins/SonarKitNetworkPlugin/SKIOSNetworkPlugin/**/*.{h,cpp,m,mm}"
     ss.pod_target_xcconfig = { "USE_HEADERMAP" => "NO",
-                                 "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)\"" }
+                                "HEADER_SEARCH_PATHS" => "\"$(PODS_ROOT)\"/Headers/Private/SonarKit/**" }
   end
 end