[vcpkg manifest] Manifest Implementation (#11757)

==== Changes Related to manifests ====

* Add the `manifests` feature flag
  * This only says whether we look for a `vcpkg.json` in the cwd, not
    whether we support parsing manifests (for ports, for example)
* Changes to the manifests RFC
  * `"authors"` -> `"maintainers"`
  * `--x-classic-mode` -> `-manifests` \in `vcpkg_feature_flags`
  * reserve `"core"` in addition to `"default"`, since that's already
    reserved for features
  * Add a small helper note about what identifiers must look like
  * `<license-string>`: SPDX v3.8 -> v3.9
  * `"feature"."description"` is allowed to be an array of strings as well
  * `"version"` -> `"version-string"` for forward-compat with versions
    RFC
* Add the `--feature-flags` option
* Add the ability to turn off feature flags via passing
  `-<feature-flag>` to `VCPKG_FEATURE_FLAGS` or `--feature-flags`
* Add CMake toolchain support for manifests
  * Requires either:
    * a feature flag of `manifests` in either `Env{VCPKG_FEATURE_FLAGS}`
      or `VCPKG_FEATURE_FLAGS`
    * Passing the `VCPKG_ENABLE_MANIFESTS` option
  * The toolchain will install your packages to
    `${VCPKG_MANIFEST_DIR}/vcpkg_installed`.
* Add MSBuild `vcpkg integrate install` support for manifests
  * Requires `VcpkgEnableManifest` to be true
* `vcpkg create` creates a port that has a `vcpkg.json` instead of a
  `CONTROL`
* argparse, abseil, 3fd, and avisynthplus ports switched to manifest
  from CONTROL
* Add support for `--x-manifest-root`, as well as code for finding it if
  not passed
* Add support for parsing manifests!
* Add a filesystem lock!

==== Important Changes which are somewhat unrelated to manifests ====

* Rename `logicexpression.{h,cpp}` to `platform-expression.{h,cpp}`
* Add `PlatformExpression` type which takes the place of the old logic
  expression
  * Split the parsing of platform expressions from checking whether
    they're true or not
  * Eagerly parse PlatformExpressions as opposed to leaving them as
    strings
* Add checking for feature flag consistency
  * i.e., if `-binarycaching` is passed, you shouldn't be passing
    `--binarysource`
* Add the `Json::Reader` type which, with the help of user-defined
  visitors, converts JSON to your internal type
* VcpkgArgParser: place the switch names into a constant as opposed to
  using magic constants
  * In general update the parsing code so that this ^ works
* Add `Port-Version` fields to CONTROL files
  * This replaces the existing practice of
    `Version: <my-version>-<port-version>`

==== Smaller changes ====
* small drive-by cleanups to some CMake
  * `${_VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}` ->
    `${CURRENT_INSTALLED_DIR}`
  * Remove `-analyze` when compiling with clang-cl, since that's not a
    supported flag (vcpkg's build system)
  * Add a message about which compiler is detected by vcpkg's build
    system machinery
* Fix `Expected::then`
* Convert `""` to `{}` for `std::string` and `fs::path`, to avoid a
  `strlen` (additionally, `.empty()` instead of `== ""`, and `.clear()`)
* Add `Strings::strto` which converts strings to numeric types
* Support built-in arrays and `StringView` for `Strings::join`
* Add `operator<` and friends to `StringView`
* Add `substr` to `StringView`
* SourceParagraphParser gets some new errors

1 files changed, 79 insertions, 5 deletions

diff --git a/scripts/buildsystems/vcpkg.cmake b/scripts/buildsystems/vcpkg.cmake
index 03926336b..10be7a423 100644
--- a/scripts/buildsystems/vcpkg.cmake
+++ b/scripts/buildsystems/vcpkg.cmake
@@ -5,6 +5,46 @@ mark_as_advanced(CMAKE_TOOLCHAIN_FILE)
 option(VCPKG_VERBOSE "Enables messages from the VCPKG toolchain for debugging purposes." OFF)
 mark_as_advanced(VCPKG_VERBOSE)
 
+function(_vcpkg_get_directory_name_of_file_above OUT DIRECTORY FILENAME)
+    if(DEFINED ${OUT})
+        return()
+    endif()
+
+    set(_vcpkg_get_dir_candidate ${DIRECTORY})
+    while(IS_DIRECTORY ${_vcpkg_get_dir_candidate} AND NOT DEFINED _vcpkg_get_dir_out)
+        if(EXISTS ${_vcpkg_get_dir_candidate}/${FILENAME})
+            set(_vcpkg_get_dir_out ${_vcpkg_get_dir_candidate})
+        else()
+            get_filename_component(_vcpkg_get_dir_candidate_tmp ${_vcpkg_get_dir_candidate} DIRECTORY)
+            if(_vcpkg_get_dir_candidate STREQUAL _vcpkg_get_dir_candidate_tmp) # we've reached the root
+                set(_vcpkg_get_dir_out "${OUT}-NOTFOUND")
+            else()
+                set(_vcpkg_get_dir_candidate ${_vcpkg_get_dir_candidate_tmp})
+            endif()
+        endif()
+    endwhile()
+
+    set(${OUT} ${_vcpkg_get_dir_out} CACHE INTERNAL "_vcpkg_get_directory_name_of_file_above: ${OUT}")
+endfunction()
+
+_vcpkg_get_directory_name_of_file_above(_VCPKG_MANIFEST_DIR ${CMAKE_CURRENT_SOURCE_DIR} "vcpkg.json")
+if(_VCPKG_MANIFEST_DIR)
+    set(_VCPKG_MANIFEST_MODE_DEFAULT ON)
+else()
+    set(_VCPKG_MANIFEST_MODE_DEFAULT OFF)
+endif()
+
+option(VCPKG_MANIFEST_MODE "Set vcpkg to manifest mode" ${_VCPKG_MANIFEST_MODE_DEFAULT})
+
+if(NOT _VCPKG_MANIFEST_DIR AND VCPKG_MANIFEST_MODE)
+    message(FATAL_ERROR
+        "vcpkg manifest mode was enabled, but we couldn't find a manifest file (vcpkg.json) "
+        "in any directories above ${CMAKE_CURRENT_SOURCE_DIR}. Please add a manifest, or "
+        "disable manifests by turning off VCPKG_MANIFEST_MODE.")
+endif()
+
+option(VCPKG_MANIFEST_INSTALL "Install packages from the manifest" ON)
+
 # Determine whether the toolchain is loaded during a try-compile configuration
 get_property(_CMAKE_IN_TRY_COMPILE GLOBAL PROPERTY IN_TRY_COMPILE)
 
@@ -144,19 +184,28 @@ if(NOT DEFINED _VCPKG_ROOT_DIR)
     while(IS_DIRECTORY ${_VCPKG_ROOT_DIR_CANDIDATE} AND NOT EXISTS "${_VCPKG_ROOT_DIR_CANDIDATE}/.vcpkg-root")
         get_filename_component(_VCPKG_ROOT_DIR_TEMP ${_VCPKG_ROOT_DIR_CANDIDATE} DIRECTORY)
         if (_VCPKG_ROOT_DIR_TEMP STREQUAL _VCPKG_ROOT_DIR_CANDIDATE) # If unchanged, we have reached the root of the drive
-            message(FATAL_ERROR "Could not find .vcpkg-root")
         else()
             SET(_VCPKG_ROOT_DIR_CANDIDATE ${_VCPKG_ROOT_DIR_TEMP})
         endif()
     endwhile()
     set(_VCPKG_ROOT_DIR ${_VCPKG_ROOT_DIR_CANDIDATE} CACHE INTERNAL "Vcpkg root directory")
 endif()
-if (NOT DEFINED _VCPKG_INSTALLED_DIR)
-    set(_VCPKG_INSTALLED_DIR ${_VCPKG_ROOT_DIR}/installed)
+
+_vcpkg_get_directory_name_of_file_above(_VCPKG_ROOT_DIR ${CMAKE_CURRENT_LIST_DIR} ".vcpkg-root")
+if(NOT _VCPKG_ROOT_DIR)
+    message(FATAL_ERROR "Could not find .vcpkg-root")
 endif()
 
-if(NOT EXISTS "${_VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}" AND NOT _CMAKE_IN_TRY_COMPILE AND NOT VCPKG_SUPPRESS_INSTALLED_LIBRARIES_WARNING)
-    message(WARNING "There are no libraries installed for the Vcpkg triplet ${VCPKG_TARGET_TRIPLET}.")
+if (NOT DEFINED _VCPKG_INSTALLED_DIR)
+    if(_VCPKG_MANIFEST_DIR)
+        set(_VCPKG_INSTALLED_DIR ${_VCPKG_MANIFEST_DIR}/vcpkg_installed)
+    else()
+        set(_VCPKG_INSTALLED_DIR ${_VCPKG_ROOT_DIR}/installed)
+    endif()
+
+    set(_VCPKG_INSTALLED_DIR ${_VCPKG_INSTALLED_DIR}
+        CACHE PATH
+        "The directory which contains the installed libraries for each triplet")
 endif()
 
 if(CMAKE_BUILD_TYPE MATCHES "^[Dd][Ee][Bb][Uu][Gg]$" OR NOT DEFINED CMAKE_BUILD_TYPE) #Debug build: Put Debug paths before Release paths.
@@ -218,6 +267,31 @@ foreach(_VCPKG_TOOLS_DIR ${_VCPKG_TOOLS_DIRS})
     endif()
 endforeach()
 
+
+# CMAKE_EXECUTABLE_SUFFIX is not yet defined
+if (CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows")
+    set(_VCPKG_EXECUTABLE_SUFFIX ".exe")
+else()
+    set(_VCPKG_EXECUTABLE_SUFFIX "")
+endif()
+
+if(VCPKG_MANIFEST_MODE AND VCPKG_MANIFEST_INSTALL AND NOT _CMAKE_IN_TRY_COMPILE)
+    execute_process(
+        COMMAND "${_VCPKG_ROOT_DIR}/vcpkg${_VCPKG_EXECUTABLE_SUFFIX}" install
+            --triplet ${VCPKG_TARGET_TRIPLET}
+            --vcpkg-root ${_VCPKG_ROOT_DIR}
+            --x-manifest-root=${_VCPKG_MANIFEST_DIR}
+            --x-install-root=${_VCPKG_INSTALLED_DIR}
+            --binarycaching
+        RESULT_VARIABLE _VCPKG_INSTALL_RESULT)
+    if (NOT _VCPKG_INSTALL_RESULT EQUAL 0)
+        message(FATAL_ERROR "vcpkg install failed")
+    endif()
+    set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS
+        "${_VCPKG_MANIFEST_DIR}/vcpkg.json"
+        "${_VCPKG_INSTALLED_DIR}/vcpkg/status")
+endif()
+
 option(VCPKG_APPLOCAL_DEPS "Automatically copy dependencies into the output directory for executables." ON)
 function(add_executable name)
     _add_executable(${ARGV})