1 files changed, 109 insertions, 0 deletions
diff --git a/lua/mason-registry/sources/synthesized.lua b/lua/mason-registry/sources/synthesized.lua
new file mode 100644
index 00000000..75638cd6
--- /dev/null
+++ b/lua/mason-registry/sources/synthesized.lua
@@ -0,0 +1,109 @@
+local Package = require "mason-core.package"
+local Result = require "mason-core.result"
+local _ = require "mason-core.functional"
+local InstallReceipt = require("mason-core.receipt").InstallReceipt
+local InstallLocation = require "mason-core.installer.InstallLocation"
+local fs = require "mason-core.fs"
+local log = require "mason-core.log"
+
+---@class SynthesizedRegistrySource : RegistrySource
+---@field buffer table<string, Package>
+local SynthesizedRegistrySource = {}
+SynthesizedRegistrySource.__index = SynthesizedRegistrySource
+
+function SynthesizedRegistrySource:new()
+    ---@type SynthesizedRegistrySource
+    local instance = {}
+    setmetatable(instance, self)
+    instance.buffer = {}
+    return instance
+end
+
+function SynthesizedRegistrySource:is_installed()
+    return true
+end
+
+---@return RegistryPackageSpec[]
+function SynthesizedRegistrySource:get_all_package_specs()
+    return {}
+end
+
+---@param pkg_name string
+---@param receipt InstallReceipt
+---@return Package
+function SynthesizedRegistrySource:load_package(pkg_name, receipt)
+    local installed_version = receipt:get_installed_package_version()
+    local source = {
+        id = ("pkg:mason/%s@%s"):format(pkg_name, installed_version or "N%2FA"), -- N%2FA = N/A
+        install = function()
+            error("This package can no longer be installed because it has been removed from the registry.", 0)
+        end,
+    }
+    ---@type RegistryPackageSpec
+    local spec = {
+        schema = "registry+v1",
+        name = pkg_name,
+        description = "",
+        categories = {},
+        languages = {},
+        homepage = "",
+        licenses = {},
+        deprecation = {
+            since = receipt:get_installed_package_version() or "N/A",
+            message = "This package has been removed from the registry.",
+        },
+        source = source,
+    }
+    local existing_pkg = self.buffer[pkg_name]
+    if existing_pkg then
+        existing_pkg:update(spec, self)
+        return existing_pkg
+    else
+        local pkg = Package:new(spec, self)
+        self.buffer[pkg_name] = pkg
+        return pkg
+    end
+end
+
+---@param pkg_name string
+---@return Package?
+function SynthesizedRegistrySource:get_package(pkg_name)
+    local receipt_path = InstallLocation.global():receipt(pkg_name)
+    if fs.sync.file_exists(receipt_path) then
+        local ok, receipt_json = pcall(vim.json.decode, fs.sync.read_file(receipt_path))
+        if ok then
+            local receipt = InstallReceipt.from_json(receipt_json)
+            return self:load_package(pkg_name, receipt)
+        else
+            log.error("Failed to decode package receipt", pkg_name, receipt_json)
+        end
+    end
+end
+
+function SynthesizedRegistrySource:get_all_package_names()
+    return vim.tbl_keys(self.buffer)
+end
+
+---@async
+function SynthesizedRegistrySource:install()
+    return Result.success()
+end
+
+function SynthesizedRegistrySource:get_display_name()
+    return "SynthesizedRegistrySource"
+end
+
+function SynthesizedRegistrySource:serialize()
+    return {}
+end
+
+---@param other SynthesizedRegistrySource
+function SynthesizedRegistrySource:is_same_location(other)
+    return true
+end
+
+function SynthesizedRegistrySource:__tostring()
+    return "SynthesizedRegistrySource"
+end
+
+return SynthesizedRegistrySource