Reorganize External dependencies.

fetchDependencies script now in top directory to avoid Travis caching of
External directory. fetchDependencies is now smart about fetching vs cloning
and building only what is necessary.

.travis.yml

@@ -7,12 +7,12 @@ osx_image: xcode9.2
 # Build dependencies
 install:
   - brew install python3
-  - ( cd External && ./fetchDependencies )
+  - ./fetchDependencies
 
 # Cache built deps
-#cache:
+cache:
-#  directories:
+  directories:
-#    - External
+    - External
 
 script:
   - xcodebuild -scheme "MoltenVK (Debug)"

ExternalRevisions/README.md

@@ -39,10 +39,9 @@ Fetching External Libraries
 - [*cereal*](https://github.com/USCiLab/cereal)
 
 These external open-source libraries are maintained in the `External` directory.
-To retrieve these libraries from their sources, run the `fetchDependencies` 
+To retrieve these libraries from their sources, run the `fetchDependencies`  script
-script in that directory:
+in the main repository directory:
 
-	cd External
 	./fetchDependencies [-sdk]
 
 The `-sdk` option tells the script that **MoltenVK** is being installed as part of 
@@ -62,13 +61,13 @@ versions of each external library. The version of each external library is
 determined as follows:
 
 - **_SPIRV-Cross_**: a GitHub repository commit identifier found in the
-  `External/SPIRV-Cross_repo_revision` file. 
+  `ExternalRevisions/SPIRV-Cross_repo_revision` file. 
   
 - **_VulkanSamples_**: a GitHub repository commit identifier found in the
-  `External/VulkanSamples_repo_revision` file.
+  `ExternalRevisions/VulkanSamples_repo_revision` file.
   
 - **_Vulkan-LoaderAndValidationLayers_**: a GitHub repository commit identifier found
-  in the `External/Vulkan-LoaderAndValidationLayers_repo_revision` file.
+  in the `ExternalRevisions/Vulkan-LoaderAndValidationLayers_repo_revision` file.
   
 - **_glslang_**: a GitHub repository commit identifier found in the retrieved 
   *Vulkan-LoaderAndValidationLayers* repository.
@@ -78,7 +77,7 @@ determined as follows:
 - **_SPIRV-Headers_**: automatically retrieved by the *glslang* repository.
 
 - **_cereal_**: a GitHub repository commit identifier found in the
-  `External/cereal_repo_revision` file. 
+  `ExternalRevisions/cereal_repo_revision` file. 
   
 You can update which versions of the *SPIRV-Cross*, *VulkanSamples*,
 *Vulkan-LoaderAndValidationLayers*, or *cereal* libraries are retrieved, 

MoltenVKPackaging.xcodeproj/project.pbxproj

@@ -137,7 +137,7 @@
 		A92DB3E61CE0F37D00FBC835 /* Whats_New.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; name = Whats_New.md; path = Docs/Whats_New.md; sourceTree = "<group>"; };
 		A92DB3EE1CE0F72500FBC835 /* MoltenVK.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = MoltenVK.xcodeproj; path = MoltenVK/MoltenVK.xcodeproj; sourceTree = "<group>"; };
 		A92DB40E1CE0F89600FBC835 /* MoltenVKShaderConverter.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = MoltenVKShaderConverter.xcodeproj; path = MoltenVKShaderConverter/MoltenVKShaderConverter.xcodeproj; sourceTree = "<group>"; };
-		A943100220546CDD00F5CF87 /* fetchDependencies */ = {isa = PBXFileReference; lastKnownFileType = text; path = fetchDependencies; sourceTree = "<group>"; };
+		A943100220546CDD00F5CF87 /* fetchDependencies */ = {isa = PBXFileReference; lastKnownFileType = text; name = fetchDependencies; path = ../fetchDependencies; sourceTree = "<group>"; };
 		A98149E51FB78829005F00B4 /* MoltenVK_Runtime_UserGuide.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; name = MoltenVK_Runtime_UserGuide.md; path = Docs/MoltenVK_Runtime_UserGuide.md; sourceTree = "<group>"; };
 		A9AD67D12054E2D700ED3C08 /* VulkanSamples_repo_revision */ = {isa = PBXFileReference; lastKnownFileType = text; path = VulkanSamples_repo_revision; sourceTree = "<group>"; };
 		A9AD67D22054E2D700ED3C08 /* Vulkan-LoaderAndValidationLayers_repo_revision */ = {isa = PBXFileReference; lastKnownFileType = text; path = "Vulkan-LoaderAndValidationLayers_repo_revision"; sourceTree = "<group>"; };
@@ -187,7 +187,8 @@
 				A9AD67D22054E2D700ED3C08 /* Vulkan-LoaderAndValidationLayers_repo_revision */,
 				A9AD67D12054E2D700ED3C08 /* VulkanSamples_repo_revision */,
 			);
-			path = External;
+			name = External;
+			path = ExternalRevisions;
 			sourceTree = "<group>";
 		};
 		A98149741FB6B565005F00B4 /* Products */ = {

README.md

@@ -67,7 +67,7 @@ Installing **MoltenVK**
 -----------------------
 
 To install **MoltenVK**, clone this `MoltenVK` repository, and then run the 
-`External/fetchDependencies` script to retrieve and build several external 
+`fetchDependencies` script to retrieve and build several external 
 open-source libraries on which **MoltenVK** relies:
 
 1. Ensure you have `cmake` and `python3` installed:
@@ -81,11 +81,11 @@ open-source libraries on which **MoltenVK** relies:
 
 3. Retrieve and build the external libraries:
 
-		cd MoltenVK/External
+		cd MoltenVK
 		./fetchDependencies
 
 For more information about the external open-source libraries used by **MoltenVK**,
-see the [`External/README.md`](External/README.md) document.
+see the [`ExternalRevisions/README.md`](ExternalRevisions/README.md) document.
 
 
 <a name="building"></a>

fetchDependencies

@@ -12,19 +12,26 @@
 
 # ----------------- Functions -------------------
 
-# Clone a repository
+# Update a repository. If it exists, fetch it, if not clone it.
 # $1 repo name
 # $2 repo url
 # $3 repo revision (commit SHA)
-clone_repo() {
+update_repo() {
 	echo "$1 repo: $2"
 	echo "$1 revision: $3"
 
+	if [ -d $1 -a -d $1/.git ]; then
+		cd $1
+		git fetch --all
+		git checkout --force $3
+		cd -
+	else
 		rm -rf $1
 		git clone $2 $1
 		cd $1
 		git checkout $3
 		cd -
+	fi
 }
 
 # Build a repository
@@ -32,8 +39,7 @@ clone_repo() {
 build_repo() {
 	echo "Building $1"
 
-	rm -rf $1/build
+	mkdir -p $1/build
-	mkdir $1/build
 	cd $1/build
 	cmake ..
 	make
@@ -41,39 +47,46 @@ build_repo() {
 }
 
 
-echo
+# ----------------- Main -------------------
-echo Retrieving MoltenVK dependencies.
-echo
 
+EXT_DIR=External
+EXT_REV_DIR=ExternalRevisions
 V_LVL_NAME=Vulkan-LoaderAndValidationLayers
 GLSLANG_NAME=glslang
 
+echo
+echo Retrieving MoltenVK dependencies into ${EXT_DIR}.
+echo
+
+mkdir -p ${EXT_DIR}
+cd ${EXT_DIR}
+
 
 # ----------------- Cereal -------------------
 
 REPO_NAME=cereal
 REPO_URL="https://github.com/USCiLab/${REPO_NAME}.git"
-REPO_REV=$(cat "./${REPO_NAME}_repo_revision")
+REPO_REV=$(cat "../${EXT_REV_DIR}/${REPO_NAME}_repo_revision")
 
-clone_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
+update_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
 
 
 # ----------------- SPIRV-Cross -------------------
 
 REPO_NAME=SPIRV-Cross
 REPO_URL="https://github.com/KhronosGroup/${REPO_NAME}.git"
-REPO_REV=$(cat "./${REPO_NAME}_repo_revision")
+REPO_REV=$(cat "../${EXT_REV_DIR}/${REPO_NAME}_repo_revision")
 
-clone_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
+update_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
 
 
 # ----------------- VulkanSamples -------------------
 
 REPO_NAME=VulkanSamples
 REPO_URL="https://github.com/brenwill/${REPO_NAME}.git"
-REPO_REV=$(cat "./${REPO_NAME}_repo_revision")
+REPO_REV=$(cat "../${EXT_REV_DIR}/${REPO_NAME}_repo_revision")
 
-clone_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
+update_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
 
 
 # ----------------- Vulkan-LoaderAndValidationLayers, glslang, SPIRV-Tools & SPIRV-Headers -------------------
@@ -96,9 +109,9 @@ else
 
 	REPO_NAME=${V_LVL_NAME}
 	REPO_URL="https://github.com/KhronosGroup/${REPO_NAME}.git"
-	REPO_REV=$(cat "./${REPO_NAME}_repo_revision")
+	REPO_REV=$(cat "../${EXT_REV_DIR}/${REPO_NAME}_repo_revision")
 
-	clone_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
+	update_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
 
 
 	# ----------------- glslang, SPIRV-Tools & SPIRV-Headers ---------------
@@ -107,13 +120,15 @@ else
 	REPO_URL=$(cat "${V_LVL_NAME}/external_revisions/glslang_giturl")
 	REPO_REV=$(cat "${V_LVL_NAME}/external_revisions/glslang_revision")
 
-	clone_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
+	update_repo ${REPO_NAME} ${REPO_URL} ${REPO_REV}
 
 	cd ${REPO_NAME}
 	./update_glslang_sources.py
 	cd -
 
-	build_repo ${GLSLANG_NAME}
+	build_repo ${REPO_NAME}
 
 fi
 
+cd ..
+