Restore [vcpkg].version functionality and add a test + documentation

Author: mrexodia

docs/examples/vcpkg.md

@@ -0,0 +1,36 @@
+---
+# Automatically generated from tests/vcpkg/cmake.toml - DO NOT EDIT
+layout: default
+title: Dependencies from vcpkg
+permalink: /examples/vcpkg
+parent: Examples
+nav_order: 4
+---
+
+# Dependencies from vcpkg
+
+Downloads [fmt v7.1.3](https://fmt.dev/7.1.3/) using [vcpkg](https://vcpkg.io/) and links an `example` target to it:
+
+```toml
+[project]
+name = "vcpkg"
+description = "Dependencies from vcpkg"
+
+# See https://github.com/microsoft/vcpkg/releases for vcpkg versions
+# See https://vcpkg.io/en/packages.html for available packages
+[vcpkg]
+version = "2021.05.12"
+packages = ["fmt"]
+
+[find-package]
+fmt = {}
+
+[target.example]
+type = "executable"
+sources = ["src/main.cpp"]
+link-libraries = ["fmt::fmt"]
+```
+
+The bootstrapping of vcpkg is fully automated and no user interaction is necessary. You can disable vcpkg by setting `CMKR_DISABLE_VCPKG=ON`.
+
+<sup><sub>This page was automatically generated from [tests/vcpkg/cmake.toml](https://github.com/build-cpp/cmkr/tree/main/tests/vcpkg/cmake.toml).</sub></sup>

include/cmake.hpp

@@ -33,6 +33,7 @@ struct Package {
 };
 
 struct Vcpkg {
+    std::string version;
     std::string url;
     std::vector<std::string> packages;
 };

src/cmake.cpp

@@ -257,7 +257,8 @@ CMake::CMake(const std::string &path, bool build) {
 
         if (toml.contains("vcpkg")) {
             const auto &v = toml::find(toml, "vcpkg");
-            vcpkg.url = toml::find(v, "url").as_string();
+            get_optional(v, "url", vcpkg.url);
+            get_optional(v, "version", vcpkg.version);
             vcpkg.packages = toml::find<decltype(vcpkg.packages)>(v, "packages");
         }
 

src/gen.cpp

@@ -163,7 +163,7 @@ struct Command {
 
     ~Command() {
         if (!generated) {
-            assert(false && "Incorrect usage of cmd()");
+            assert(false && "Incorrect usage of cmd(), you probably forgot ()");
         }
     }
 
@@ -297,7 +297,7 @@ struct Command {
     }
 
     template <class... Ts>
-    CommandEndl operator()(Ts &&... values) {
+    CommandEndl operator()(Ts &&...values) {
         generated = true;
         ss << indent(depth) << command << '(';
         (void)std::initializer_list<bool>{print_arg(values)...};
@@ -406,6 +406,31 @@ struct Generator {
     }
 };
 
+static std::string vcpkg_escape_identifier(const std::string &name) {
+    // Do a reasonable effort to escape the project name for use with vcpkg
+    std::string escaped;
+    for (char ch : name) {
+        if ((ch & 0x80) != 0) {
+            throw std::runtime_error("Non-ASCII characters are not allowed in [project].name when using [vcpkg]");
+        }
+
+        if (ch == '_' || ch == ' ') {
+            ch = '-';
+        }
+
+        escaped += std::tolower(ch);
+    }
+
+    const std::regex reserved("prn|aux|nul|con|lpt[1-9]|com[1-9]|core|default");
+    const std::regex ok("[a-z0-9]+(-[a-z0-9]+)*");
+    std::cmatch m;
+    if (!std::regex_match(escaped.c_str(), m, reserved) && std::regex_match(escaped.c_str(), m, ok)) {
+        return escaped;
+    } else {
+        throw std::runtime_error("The escaped project name '" + escaped + "' is not usable with [vcpkg]");
+    }
+}
+
 int generate_cmake(const char *path, bool root) {
     if (!fs::exists(fs::path(path) / "cmake.toml")) {
         throw std::runtime_error("No cmake.toml found!");
@@ -422,8 +447,9 @@ int generate_cmake(const char *path, bool root) {
     auto inject_includes = [&gen](const std::vector<std::string> &includes) { gen.inject_includes(includes); };
     auto inject_cmake = [&gen](const std::string &cmake) { gen.inject_cmake(cmake); };
 
+    std::string cmkr_url = "https://github.com/build-cpp/cmkr";
     comment("This file is automatically generated from cmake.toml - DO NOT EDIT");
-    comment("See https://github.com/build-cpp/cmkr for more information");
+    comment("See " + cmkr_url + " for more information");
     endl();
 
     if (root) {
@@ -523,30 +549,40 @@ int generate_cmake(const char *path, bool root) {
         }
     }
 
-    if (!cmake.vcpkg.packages.empty() && !cmake.vcpkg.url.empty()) {
-        auto vcpkg_escape_identifier = [](const std::string &name) -> std::string {
-            const std::regex ok("[a-z0-9]+(-[a-z0-9]+)*");
-            const std::regex reserved("prn|aux|nul|con|lpt[1-9]|com[1-9]|core|default");
-            std::cmatch m;
-            if (!std::regex_match(name.c_str(), m, reserved) && std::regex_match(name.c_str(), m, ok)) {
-                return name;
-            } else {
-                // should probably throw!
-                return "project-name";
+    if (!cmake.vcpkg.packages.empty()) {
+        // Allow the user to specify a url or derive it from the version
+        auto url = cmake.vcpkg.url;
+        if (url.empty()) {
+            if (cmake.vcpkg.version.empty()) {
+                throw std::runtime_error("You need either [vcpkg].version or [vcpkg].url");
             }
-        };
+            url = "https://github.com/microsoft/vcpkg/archive/refs/tags/" + cmake.vcpkg.version + ".tar.gz";
+        }
+
+        // CMake to bootstrap vcpkg and download the packages
+        // clang-format off
+        cmd("if")("CMKR_ROOT_PROJECT", "AND", "NOT", "CMKR_DISABLE_VCPKG");
+            cmd("include")("FetchContent");
+            cmd("message")("STATUS", "Fetching vcpkg...");
+            cmd("FetchContent_Declare")("vcpkg", "URL", url);
+            cmd("FetchContent_MakeAvailable")("vcpkg");
+            cmd("include")("${vcpkg_SOURCE_DIR}/scripts/buildsystems/vcpkg.cmake");
+        cmd("endif")();
+        // clang-format on
+
+        // Generate vcpkg.json
         using namespace nlohmann;
         json j;
+        j["$cmkr"] = "This file is automatically generated from cmake.toml - DO NOT EDIT";
+        j["$cmkr-url"] = cmkr_url;
         j["$schema"] = "https://raw.githubusercontent.com/microsoft/vcpkg/master/scripts/vcpkg.schema.json";
         j["name"] = vcpkg_escape_identifier(cmake.project_name);
-        if (!cmake.project_version.empty())
-            j["version"] = cmake.project_version;
+        j["version-string"] = cmake.project_version;
         j["dependencies"] = cmake.vcpkg.packages;
-        cmd("include")("FetchContent");
-        cmd("message")("STATUS", "Fetching vcpkg...");
-        cmd("FetchContent_Declare")("vcpkg", "URL", cmake.vcpkg.url);
-        cmd("FetchContent_MakeAvailable")("vcpkg");
-        cmd("include")("${vcpkg_SOURCE_DIR}/scripts/buildsystems/vcpkg.cmake");
+        if (!cmake.project_description.empty()) {
+            j["description"] = cmake.project_description;
+        }
+
         std::ofstream ofs("vcpkg.json");
         if (!ofs) {
             throw std::runtime_error("Failed to create a vcpkg.json manifest file!");

tests/CMakeLists.txt

@@ -20,4 +20,10 @@ arguments = ["build"]
 name = "conditions"
 command = "$<TARGET_FILE:cmkr>"
 working-directory = "conditions"
+arguments = ["build"]
+
+[[test]]
+name = "vcpkg"
+command = "$<TARGET_FILE:cmkr>"
+working-directory = "vcpkg"
 arguments = ["build"]

tests/cmake.toml

@@ -0,0 +1,21 @@
+# Downloads [fmt v7.1.3](https://fmt.dev/7.1.3/) using [vcpkg](https://vcpkg.io/) and links an `example` target to it:
+
+[project]
+name = "vcpkg"
+description = "Dependencies from vcpkg"
+
+# See https://github.com/microsoft/vcpkg/releases for vcpkg versions
+# See https://vcpkg.io/en/packages.html for available packages
+[vcpkg]
+version = "2021.05.12"
+packages = ["fmt"]
+
+[find-package]
+fmt = {}
+
+[target.example]
+type = "executable"
+sources = ["src/main.cpp"]
+link-libraries = ["fmt::fmt"]
+
+# The bootstrapping of vcpkg is fully automated and no user interaction is necessary. You can disable vcpkg by setting `CMKR_DISABLE_VCPKG=ON`.

tests/vcpkg/cmake.toml

@@ -0,0 +1,6 @@
+#include <fmt/core.h>
+
+int main()
+{
+    fmt::print("Hello, world!\n");
+}

tests/vcpkg/src/main.cpp

@@ -0,0 +1,11 @@
+{
+  "$cmkr": "This file is automatically generated from cmake.toml - DO NOT EDIT",
+  "$cmkr-url": "https://github.com/build-cpp/cmkr",
+  "$schema": "https://raw.githubusercontent.com/microsoft/vcpkg/master/scripts/vcpkg.schema.json",
+  "dependencies": [
+    "fmt"
+  ],
+  "description": "Example of using vcpkg",
+  "name": "vcpkg",
+  "version-string": ""
+}