cmake, ci: Add caching support to speed up builds

.github/workflows/main.yml

@@ -2,14 +2,6 @@ name: Build
 
 on: 
   push:
-    tags:
-      - '[0-9].[0-9].[0-9]'
-      - '[0-9].[1-9][0-9].[1-9][0-9]'
-      - '[0-9].[1-9][0-9].[0-9]'
-      - '[1-9][0-9].[1-9][0-9].[1-9][0-9]'
-      - '[1-9][0-9].[1-9][0-9].[0-9]'
-      - '[1-9][0-9].[0-9].[1-9][0-9]'
-      - '[1-9][0-9].[0-9].[0-9]'
     branches-ignore:
       - 'l10n_master'
   pull_request:
@@ -40,6 +32,14 @@ jobs:
     - name: "Clone Submodules"
       shell: bash
       run: git submodule update --init --recursive
+    - name: "Cache: Prerequisites"
+      uses: actions/cache@v2
+      with:
+        path: |
+          build/temp/qt-download/qt-download-prefix/src/qt.7z
+          build/temp/obsdeps-download/obsdeps-download-prefix/src/obsdeps.7z
+          build/temp/libobs-download/libobs-download-prefix/src/libobs.7z
+        key: ${{ matrix.id }}
     - name: "Configure Project"
       shell: bash
       run: |
@@ -143,6 +143,12 @@ jobs:
           git \
           qt5-default libqwt-qt5-dev libqt5svg5-dev
         ${{ matrix.extra_command }}
+    - name: "Cache: Prerequisites"
+      uses: actions/cache@v2
+      with:
+        path: |
+          build/temp/libobs-download/libobs-download-prefix/src/libobs.7z
+        key: ${{ matrix.id }}
     - name: "Configure Project"
       shell: bash
       run: |

CMakeLists.txt

@@ -317,26 +317,45 @@ if(NOT TARGET libobs)
 		set(OBS_DOWNLOAD_VERSION "25.0.3-fe-ci")
 		if(WIN32)
 			# Windows
+			set(OBS_DOWNLOAD_HASH_32 "SHA512=C8CABFAA59BDF5E4CD1C69CBC349F3E62FD6FE37A1A1A8BE4AC1B37BF087F597A313B2B004E019827C43A5951B50957B60578B7F2249383C117E634FD8714844")
+			set(OBS_DOWNLOAD_HASH_64 "SHA512=75E83548AD8FD994D45BE2395E97499BED8444C245857C811BA44D35BF3C49186B1187D3EF250F2618295D7AFA7D8ED5A66582BD140A01A46A77F6BC19BDDBE2")
 			set(OBS_DEPENDENCIES_VERSION "25.0.0")
+			set(OBS_DEPENDENCIES_HASH "SHA512=7545696B5B684E6BF57F11158FBDF7A0477C4C2CBB872070105A400E56ACD16A54934928BB917E8C952631667DB63953B56F8BACB9C52D36285EA3DD83B9F473")
 			set(OBS_QT_VERSION "5.10.1")
+			set(OBS_QT_HASH "SHA512=848B9AC00B06FCA1F1A85BD4EFEA4138D278E8EC96823C5C36CC988DDE5D27E2F91300B02F2F0E71F075CCB0D791D3C888CDA6A5048DDFE6F946A8697DFEF1E9")
 
 			download_project(
 				PROJ libobs
 				URL https://github.com/Xaymar/obs-studio/releases/download/${OBS_DOWNLOAD_VERSION}/obs-studio-${ARCH}-0.0.0.0-vs2019.7z
-				UPDATE_DISCONNECTED 1
+				URL_HASH "${OBS_DOWNLOAD_HASH_${ARCH}}"
+				DOWNLOAD_NAME "libobs.7z"
+				DOWNLOAD_NO_PROGRESS ON
+				UPDATE_DISCONNECTED ON
+				QUIET
 			)
 
 			download_project(
 				PROJ obsdeps
 				URL https://cdn.xaymar.com/obs/dependencies_${OBS_DEPENDENCIES_VERSION}.7z
-				UPDATE_DISCONNECTED 1
+				URL_HASH "${OBS_DEPENDENCIES_HASH}"
+				DOWNLOAD_NAME "obsdeps.7z"
+				DOWNLOAD_NO_PROGRESS ON
+				UPDATE_DISCONNECTED ON
+				QUIET
 			)
 		elseif(UNIX)
 			# Unix, Linux
+			set(OBS_DOWNLOAD_HASH_32 "")
+			set(OBS_DOWNLOAD_HASH_64 "SHA512=EAB0450F4B3D9C6252C347CD138A4AB49725CF930A742FF6D1EAEADDEDE31627D1C0A45831FE26A19C0B278386A476736CAA170B351EF833E8A5E8DAD6BB57D2")
+			
 			download_project(
 				PROJ libobs
 				URL https://github.com/Xaymar/obs-studio/releases/download/${OBS_DOWNLOAD_VERSION}/obs-studio-${ARCH}-0.0.0.0-ubuntu1804.7z
-				UPDATE_DISCONNECTED 1
+				URL_HASH "${OBS_DOWNLOAD_HASH_${ARCH}}"
+				DOWNLOAD_NAME "libobs.7z"
+				DOWNLOAD_NO_PROGRESS ON
+				UPDATE_DISCONNECTED ON
+				QUIET
 			)
 
 			# Dependencies must be installed like normal OBS Studio
@@ -374,7 +393,11 @@ if(NOT TARGET libobs)
 				download_project(
 					PROJ qt
 					URL https://cdn.xaymar.com/obs/qt_${OBS_QT_VERSION}.7z
-					UPDATE_DISCONNECTED 1
+					URL_HASH "${OBS_QT_HASH}"
+					DOWNLOAD_NAME "qt.7z"
+					DOWNLOAD_NO_PROGRESS ON
+					UPDATE_DISCONNECTED ON
+					QUIET
 				)
 
 				set(Qt5_DIR "${qt_SOURCE_DIR}" CACHE STRING "Path to Qt5")