Move the FileSpec from src/core/obj.js and into its own file

The size of the `src/core/obj.js` file has increased slowly over the years, and it also contains a fair amount of *distinct* functionality.
In order to improve readability and make it easier to navigate through the code, this patch moves the `FileSpec` into its own file.

src/core/annotation.js

@@ -34,7 +34,6 @@ import {
   Util,
   warn,
 } from "../shared/util.js";
-import { Catalog, FileSpec } from "./obj.js";
 import { collectActions, getInheritableProperty } from "./core_utils.js";
 import {
   createDefaultAppearance,
@@ -49,7 +48,9 @@ import {
   Name,
   RefSet,
 } from "./primitives.js";
+import { Catalog } from "./obj.js";
 import { ColorSpace } from "./colorspace.js";
+import { FileSpec } from "./file_spec.js";
 import { ObjectLoader } from "./object_loader.js";
 import { OperatorList } from "./operator_list.js";
 import { StringStream } from "./stream.js";

src/core/file_spec.js

@@ -0,0 +1,113 @@
+/* Copyright 2021 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/* eslint-disable no-var */
+
+import { isDict, isStream } from "./primitives.js";
+import { stringToPDFString, warn } from "../shared/util.js";
+
+/**
+ * "A PDF file can refer to the contents of another file by using a File
+ * Specification (PDF 1.1)", see the spec (7.11) for more details.
+ * NOTE: Only embedded files are supported (as part of the attachments support)
+ * TODO: support the 'URL' file system (with caching if !/V), portable
+ * collections attributes and related files (/RF)
+ */
+var FileSpec = (function FileSpecClosure() {
+  // eslint-disable-next-line no-shadow
+  function FileSpec(root, xref) {
+    if (!root || !isDict(root)) {
+      return;
+    }
+    this.xref = xref;
+    this.root = root;
+    if (root.has("FS")) {
+      this.fs = root.get("FS");
+    }
+    this.description = root.has("Desc")
+      ? stringToPDFString(root.get("Desc"))
+      : "";
+    if (root.has("RF")) {
+      warn("Related file specifications are not supported");
+    }
+    this.contentAvailable = true;
+    if (!root.has("EF")) {
+      this.contentAvailable = false;
+      warn("Non-embedded file specifications are not supported");
+    }
+  }
+
+  function pickPlatformItem(dict) {
+    // Look for the filename in this order:
+    // UF, F, Unix, Mac, DOS
+    if (dict.has("UF")) {
+      return dict.get("UF");
+    } else if (dict.has("F")) {
+      return dict.get("F");
+    } else if (dict.has("Unix")) {
+      return dict.get("Unix");
+    } else if (dict.has("Mac")) {
+      return dict.get("Mac");
+    } else if (dict.has("DOS")) {
+      return dict.get("DOS");
+    }
+    return null;
+  }
+
+  FileSpec.prototype = {
+    get filename() {
+      if (!this._filename && this.root) {
+        var filename = pickPlatformItem(this.root) || "unnamed";
+        this._filename = stringToPDFString(filename)
+          .replace(/\\\\/g, "\\")
+          .replace(/\\\//g, "/")
+          .replace(/\\/g, "/");
+      }
+      return this._filename;
+    },
+    get content() {
+      if (!this.contentAvailable) {
+        return null;
+      }
+      if (!this.contentRef && this.root) {
+        this.contentRef = pickPlatformItem(this.root.get("EF"));
+      }
+      var content = null;
+      if (this.contentRef) {
+        var xref = this.xref;
+        var fileObj = xref.fetchIfRef(this.contentRef);
+        if (fileObj && isStream(fileObj)) {
+          content = fileObj.getBytes();
+        } else {
+          warn(
+            "Embedded file specification points to non-existing/invalid " +
+              "content"
+          );
+        }
+      } else {
+        warn("Embedded file specification does not have a content");
+      }
+      return content;
+    },
+    get serializable() {
+      return {
+        filename: this.filename,
+        content: this.content,
+      };
+    },
+  };
+  return FileSpec;
+})();
+
+export { FileSpec };

src/core/obj.js

@@ -58,6 +58,7 @@ import {
 import { Lexer, Parser } from "./parser.js";
 import { CipherTransformFactory } from "./crypto.js";
 import { ColorSpace } from "./colorspace.js";
+import { FileSpec } from "./file_spec.js";
 import { GlobalImageCache } from "./image_utils.js";
 import { MetadataParser } from "./metadata_parser.js";
 import { StructTreeRoot } from "./struct_tree.js";
@@ -2419,97 +2420,4 @@ class NumberTree extends NameOrNumberTree {
   }
 }
 
-/**
+export { Catalog, NumberTree, XRef };
- * "A PDF file can refer to the contents of another file by using a File
- * Specification (PDF 1.1)", see the spec (7.11) for more details.
- * NOTE: Only embedded files are supported (as part of the attachments support)
- * TODO: support the 'URL' file system (with caching if !/V), portable
- * collections attributes and related files (/RF)
- */
-var FileSpec = (function FileSpecClosure() {
-  // eslint-disable-next-line no-shadow
-  function FileSpec(root, xref) {
-    if (!root || !isDict(root)) {
-      return;
-    }
-    this.xref = xref;
-    this.root = root;
-    if (root.has("FS")) {
-      this.fs = root.get("FS");
-    }
-    this.description = root.has("Desc")
-      ? stringToPDFString(root.get("Desc"))
-      : "";
-    if (root.has("RF")) {
-      warn("Related file specifications are not supported");
-    }
-    this.contentAvailable = true;
-    if (!root.has("EF")) {
-      this.contentAvailable = false;
-      warn("Non-embedded file specifications are not supported");
-    }
-  }
-
-  function pickPlatformItem(dict) {
-    // Look for the filename in this order:
-    // UF, F, Unix, Mac, DOS
-    if (dict.has("UF")) {
-      return dict.get("UF");
-    } else if (dict.has("F")) {
-      return dict.get("F");
-    } else if (dict.has("Unix")) {
-      return dict.get("Unix");
-    } else if (dict.has("Mac")) {
-      return dict.get("Mac");
-    } else if (dict.has("DOS")) {
-      return dict.get("DOS");
-    }
-    return null;
-  }
-
-  FileSpec.prototype = {
-    get filename() {
-      if (!this._filename && this.root) {
-        var filename = pickPlatformItem(this.root) || "unnamed";
-        this._filename = stringToPDFString(filename)
-          .replace(/\\\\/g, "\\")
-          .replace(/\\\//g, "/")
-          .replace(/\\/g, "/");
-      }
-      return this._filename;
-    },
-    get content() {
-      if (!this.contentAvailable) {
-        return null;
-      }
-      if (!this.contentRef && this.root) {
-        this.contentRef = pickPlatformItem(this.root.get("EF"));
-      }
-      var content = null;
-      if (this.contentRef) {
-        var xref = this.xref;
-        var fileObj = xref.fetchIfRef(this.contentRef);
-        if (fileObj && isStream(fileObj)) {
-          content = fileObj.getBytes();
-        } else {
-          warn(
-            "Embedded file specification points to non-existing/invalid " +
-              "content"
-          );
-        }
-      } else {
-        warn("Embedded file specification does not have a content");
-      }
-      return content;
-    },
-    get serializable() {
-      return {
-        filename: this.filename,
-        content: this.content,
-      };
-    },
-  };
-  return FileSpec;
-})();
-
-export { Catalog, FileSpec, NumberTree, XRef };