Add SkPDFResourceDict class, refactor existing code

src/pdf/SkPDFResourceDict.h

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPDFResourceDict_DEFINED
+#define SkPDFResourceDict_DEFINED
+
+#include "SkPDFTypes.h"
+#include "SkTDArray.h"
+#include "SkTSet.h"
+#include "SkTypes.h"
+
+/** \class SkPDFResourceDict
+
+    A resource dictionary, which maintains the relevant sub-dicts and
+    allows generation of a list of referenced SkPDFObjects inserted with
+    insertResourceAsRef.
+*/
+class SkPDFResourceDict : public SkPDFDict {
+public:
+    SK_DECLARE_INST_COUNT(SkPDFResourceDict)
+
+     enum SkPDFResourceType{
+        kExtGState_ResourceType,
+        kPattern_ResourceType,
+        kXObject_ResourceType,
+        kFont_ResourceType,
+        // These additional types are defined by the spec, but not
+        // currently used by Skia: ColorSpace, Shading, Properties
+        kResourceTypeCount
+     };
+
+    /** Create a PDF resource dictionary.
+     *  The full set of ProcSet entries is automatically created for backwards
+     *  compatibility, as recommended by the PDF spec.
+     */
+    SkPDFResourceDict();
+
+    /** Add the value SkPDFObject as a reference to the resource dictionary
+     *  with the give type and key.
+     *  The relevant sub-dicts will be automatically generated, and the
+     *  resource will be named by concatenating a type-specific prefix and
+     *  the input key.
+     *  This object will be part of the resource list when requested later.
+     *  @param type  The type of resource being entered, like
+     *    kPattern_ResourceType or kExtGState_ResourceType.
+     *  @param key   The resource key, should be unique within its type.
+     *  @param value The resource itself.
+     *  @return The value argument is returned.
+     */
+    SkPDFObject* insertResourceAsRef(SkPDFResourceType type, int key,
+                                     SkPDFObject* value);
+
+    /**
+     * Gets resources inserted into this dictionary as a reference.
+     *
+     * @param knownResourceObjects Set containing currently known resources.
+     *     Resources in the dict and this set will not be added to the output.
+     * @param newResourceObjects   Output set to which non-preexisting resources
+     *     will be added.
+     * @param recursive            Whether or not to add resources of resources.
+     */
+    void getRefResources(
+            const SkTSet<SkPDFObject*>& knownResourceObjects,
+            SkTSet<SkPDFObject*>* newResourceObjects,
+            bool recursive) const;
+
+    /**
+     * Returns the name for the resource that will be generated by the resource
+     * dict.
+     *
+     *  @param type  The type of resource being entered, like
+     *    kPattern_ResourceType or kExtGState_ResourceType.
+     *  @param key   The resource key, should be unique within its type.
+     */
+    static SkString getResourceName(SkPDFResourceType type, int key);
+
+private:
+    /** Add the value to the dictionary with the given key.  Refs value.
+     *  The relevant sub-dicts will be automatically generated, and the
+     *  resource will be named by concatenating a type-specific prefix and
+     *  the input key.
+     *  The object will NOT be part of the resource list when requested later.
+     *  @param type  The type of resource being entered.
+     *  @param key   The resource key, should be unique within its type.
+     *  @param value The resource itself.
+     *  @return The value argument is returned.
+     */
+    SkPDFObject* insertResource(SkPDFResourceType type, int key,
+                                SkPDFObject* value);
+
+    SkTSet<SkPDFObject*> fResources;
+
+    SkTDArray<SkPDFDict*> fTypes;
+};
+
+#endif