Merge 83d6b83 into b24f06a

src/dhall_clj/fail.clj

@@ -47,6 +47,7 @@
 (ex/derive ::missing-file    ::imports)
 (ex/derive ::missing-imports ::imports)
 (ex/derive ::cyclic-import   ::imports)
+(ex/derive ::hash-mismatch   ::imports)
 
 (defn missing-keyword!
   "Throws an ex-info from the `missing` keyword"
@@ -88,6 +89,15 @@
     {:type ::cyclic-import
      :import import}))
 
+(defn hash-mismatch!
+  "Throws an ex-info on hash protection mismatch"
+  [import actual-hash expression]
+  (throw-data
+    "Hash mismatch"
+    {:type ::hash-mismatch
+     :import import
+     :actual-hash actual-hash
+     :expression expression}))
 
 ;;
 ;; Serialization

src/dhall_clj/import.clj

@@ -7,6 +7,8 @@
             [dhall-clj.parse :refer [parse expr]]
             [dhall-clj.state :as state]
             [dhall-clj.fail :as fail]
+            [dhall-clj.alpha-normalize :refer [alpha-normalize]]
+            [dhall-clj.binary :as binary]
             [clojure.string :as str]
             [dhall-clj.state :as s])
   (:import [dhall_clj.ast Import Local Remote Env Missing]))
@@ -135,8 +137,18 @@
               resolved-expr (resolve-imports
                               dynamic-expr
                               (update state :stack conj data))]
-          ;; TODO: typecheck + normalize
-          resolved-expr))))
+          ;; TODO: typecheck + normalize resolved-expr
+          (if-not hash?
+            resolved-expr
+            ;; TODO TEST THIS
+            (let [expected-hash (str/lower-case hash?)
+                  actual-hash   (-> resolved-expr
+                                   alpha-normalize
+                                   binary/encode
+                                   sha-256)]
+              (if (= expected-hash actual-hash)
+                resolved-expr
+                (fail/hash-mismatch! this actual-hash resolved-expr))))))))
 
   dhall_clj.ast.ImportAlt
   (resolve-imports [this state]