Revert "Move data part of dub.platform to dub.data"

This reverts commit a0d80e8.
The approach might be wrong headed and will be reverted until
a more comprehensive diff can be submitted.

Author: Geod24

build-files.txt

@@ -6,7 +6,6 @@ source/dub/compilers/dmd.d
 source/dub/compilers/gdc.d
 source/dub/compilers/ldc.d
 source/dub/compilers/utils.d
-source/dub/data/platform.d
 source/dub/data/settings.d
 source/dub/dependency.d
 source/dub/dependencyresolver.d

source/dub/compilers/compiler.d

@@ -9,7 +9,7 @@ module dub.compilers.compiler;
 
 public import dub.compilers.buildsettings;
 deprecated("Please `import dub.dependency : Dependency` instead") public import dub.dependency : Dependency;
-public import dub.data.platform : BuildPlatform, matchesSpecification;
+public import dub.platform : BuildPlatform, matchesSpecification;
 
 import dub.internal.vibecompat.inet.path;
 import dub.internal.vibecompat.core.file;

source/dub/data/platform.d

@@ -15,7 +15,6 @@
 module dub.platform;
 
 import std.array;
-public import dub.data.platform;
 
 // archCheck, compilerCheck, and platformCheck are used below and in
 // generatePlatformProbeFile, so they've been extracted into these strings
@@ -171,3 +170,119 @@ string determineCompiler()
 {
 	mixin(compilerCheck);
 }
+
+/** Matches a platform specification string against a build platform.
+
+	Specifications are build upon the following scheme, where each component
+	is optional (indicated by []), but the order is obligatory:
+	"[-platform][-architecture][-compiler]"
+
+	So the following strings are valid specifications: `"-windows-x86-dmd"`,
+	`"-dmd"`, `"-arm"`, `"-arm-dmd"`, `"-windows-dmd"`
+
+	Params:
+		platform = The build platform to match against the platform specification
+	    specification = The specification being matched. It must either be an
+	    	empty string or start with a dash.
+
+	Returns:
+	    `true` if the given specification matches the build platform, `false`
+	    otherwise. Using an empty string as the platform specification will
+	    always result in a match.
+*/
+bool matchesSpecification(in BuildPlatform platform, const(char)[] specification)
+{
+	import std.string : chompPrefix, format;
+	import std.algorithm : canFind, splitter;
+	import std.exception : enforce;
+
+	if (specification.empty) return true;
+	if (platform == BuildPlatform.any) return true;
+
+	auto splitted = specification.chompPrefix("-").splitter('-');
+	enforce(!splitted.empty, format("Platform specification, if present, must not be empty: \"%s\"", specification));
+
+	if (platform.platform.canFind(splitted.front)) {
+		splitted.popFront();
+		if (splitted.empty)
+			return true;
+	}
+	if (platform.architecture.canFind(splitted.front)) {
+		splitted.popFront();
+		if (splitted.empty)
+			return true;
+	}
+	if (platform.compiler == splitted.front) {
+		splitted.popFront();
+		enforce(splitted.empty, "No valid specification! The compiler has to be the last element: " ~ specification);
+		return true;
+	}
+	return false;
+}
+
+///
+unittest {
+	auto platform = BuildPlatform(["posix", "linux"], ["x86_64"], "dmd");
+	assert(platform.matchesSpecification(""));
+	assert(platform.matchesSpecification("posix"));
+	assert(platform.matchesSpecification("linux"));
+	assert(platform.matchesSpecification("linux-dmd"));
+	assert(platform.matchesSpecification("linux-x86_64-dmd"));
+	assert(platform.matchesSpecification("x86_64"));
+	assert(!platform.matchesSpecification("windows"));
+	assert(!platform.matchesSpecification("ldc"));
+	assert(!platform.matchesSpecification("windows-dmd"));
+
+	// Before PR#2279, a leading '-' was required
+	assert(platform.matchesSpecification("-x86_64"));
+}
+
+/// Represents a platform a package can be build upon.
+struct BuildPlatform {
+	/// Special constant used to denote matching any build platform.
+	enum any = BuildPlatform(null, null, null, null, -1);
+
+	/// Platform identifiers, e.g. ["posix", "windows"]
+	string[] platform;
+	/// CPU architecture identifiers, e.g. ["x86", "x86_64"]
+	string[] architecture;
+	/// Canonical compiler name e.g. "dmd"
+	string compiler;
+	/// Compiler binary name e.g. "ldmd2"
+	string compilerBinary;
+	/// Compiled frontend version (e.g. `2067` for frontend versions 2.067.x)
+	int frontendVersion;
+	/// Compiler version e.g. "1.11.0"
+	string compilerVersion;
+	/// Frontend version string from frontendVersion
+	/// e.g: 2067 => "2.067"
+	string frontendVersionString() const
+	{
+		import std.format : format;
+
+		const maj = frontendVersion / 1000;
+		const min = frontendVersion % 1000;
+		return format("%d.%03d", maj, min);
+	}
+	///
+	unittest
+	{
+		BuildPlatform bp;
+		bp.frontendVersion = 2067;
+		assert(bp.frontendVersionString == "2.067");
+	}
+
+	/// Checks to see if platform field contains windows
+	bool isWindows() const {
+		import std.algorithm : canFind;
+		return this.platform.canFind("windows");
+	}
+	///
+	unittest {
+		BuildPlatform bp;
+		bp.platform = ["windows"];
+		assert(bp.isWindows);
+		bp.platform = ["posix"];
+		assert(!bp.isWindows);
+	}
+}