Support for "master" and update to latest version

src/main.zig

@@ -50,7 +50,7 @@ pub fn main() !void {
 
     var needtofree_ = true;
 
-    const zig_version = std.fs.cwd().readFileAlloc(allocator, "zigd.ver", 1 << 21) catch blk: {
+    var zig_version = std.fs.cwd().readFileAlloc(allocator, "zigd.ver", 1 << 21) catch blk: {
         needtofree_ = false;
 
         var absolutecwd = try std.fs.cwd().realpathAlloc(allocator, ".");
@@ -71,6 +71,11 @@ pub fn main() !void {
         @panic("No default/workspace version set in config file, and no zigd.ver file found in current directory.");
     };
 
+    if (std.mem.eql(u8, zig_version, "master")) {
+        if (needtofree_) allocator.free(zig_version);
+        zig_version = try zigd.masterFromIndex(allocator);
+    }
+
     defer _ = if (needtofree_) allocator.free(zig_version);
 
     const zig_binary = try try_get_bin: {

src/zigd.zig

@@ -21,8 +21,59 @@ const os = switch (builtin.os.tag) {
 const url_platform = os ++ "-" ++ arch;
 const archive_ext = if (builtin.os.tag == .windows) "zip" else "tar.xz"; // Maybe Windows support in future?
 
+// Fetches from "https://ziglang.org/download/index.json"
+const index_url = "https://ziglang.org/download/index.json";
+
+pub fn masterFromIndex(allocator: std.mem.Allocator) ![]const u8 {
+    var client = std.http.Client{ .allocator = allocator };
+    defer client.deinit();
+
+    var headers = std.http.Headers.init(allocator);
+    defer headers.deinit();
+
+    try headers.append("Content-Type", "application/json");
+
+    var req = try client.fetch(allocator, .{
+        .method = .GET,
+        .headers = headers,
+        .location = .{
+            .url = index_url,
+        },
+    });
+    defer req.deinit();
+
+    if (req.status.class() != .success or req.body == null) {
+        return error.ResponseWasNotOk;
+    }
+
+    const json = try std.json.parseFromSlice(std.json.Value, allocator, req.body.?, .{});
+    defer json.deinit();
+
+    const master = json.value.object.get("master") orelse return error.MasterNotFound;
+    const version = master.object.get("version") orelse return error.VersionNotFound;
+
+    if (version != .string) {
+        return error.VersionNotString;
+    }
+
+    return try allocator.dupe(u8, version.string);
+}
+
 /// Do not forget to free the returned value!
-pub fn install(allocator: std.mem.Allocator, version: []const u8, home: []const u8) ![]const u8 {
+pub fn install(allocator: std.mem.Allocator, given_version: []const u8, home: []const u8) ![]const u8 {
+    var free_s: bool = false;
+
+    var version = vl: {
+        if (std.mem.eql(u8, given_version, "master")) {
+            free_s = true;
+            break :vl try masterFromIndex(allocator);
+        } else {
+            break :vl given_version;
+        }
+    };
+
+    defer if (free_s) allocator.free(version) else void{};
+
     const url = try std.fmt.allocPrint(allocator, "https://ziglang.org/builds/zig-{s}-{s}.{s}", .{ url_platform, version, archive_ext });
     defer allocator.free(url);
 
@@ -34,19 +85,16 @@ pub fn install(allocator: std.mem.Allocator, version: []const u8, home: []const
     var headers = std.http.Headers.init(allocator);
     defer headers.deinit();
 
-    var req = try client.request(.GET, uri, headers, .{});
+    var req = try client.open(.GET, uri, headers, .{});
     defer req.deinit();
 
-    try req.start(.{});
+    try req.send(.{});
     try req.finish();
     try req.wait();
 
     if (req.response.status != .ok)
         @panic("Response was not ok!");
 
-    var zigdir = try fromHome(home, "zig");
-    _ = zigdir;
-
     const data = try req.reader().readAllAlloc(allocator, 2 << 50);
     defer allocator.free(data);
 

zigd.ver

@@ -1 +1 @@
-0.12.0-dev.935+a1e0b9979
+0.12.0-dev.1298+da06269d7