Implement a JavaScript API for document scanning

chrome/browser/extensions/api/document_scan/document_scan_api.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <string>
+#include <vector>
+
+#include "base/base64.h"
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/common/extensions/api/document_scan.h"
+#include "extensions/browser/api/async_api_function.h"
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_DOCUMENT_SCAN_DOCUMENT_SCAN_API_H_
+#define CHROME_BROWSER_EXTENSIONS_API_DOCUMENT_SCAN_DOCUMENT_SCAN_API_H_
+
+namespace base {
+class ListValue;
+}
+
+namespace extensions {
+
+namespace api {
+
+// Per-platform back-end implementation for each of the functions below.
+class DocumentScanInterface {

[mef, 2014/10/13 15:59:54]

suggest: put this class into document_scan_interface.h

[Paul Stewart, 2014/10/14 19:28:31]

Done.

+ public:
+  struct ScannerDescription {
+    std::string name;
+    std::string manufacturer;
+    std::string model;
+    std::string scanner_type;
+    std::string image_mime_type;
+  };
+
+  enum ScanMode {
+    kScanModeColor,
+    kScanModeGray,
+    kScanModeLineart
+  };
+
+  typedef base::Callback<void(
+      const std::vector<ScannerDescription>& scanner_descriptions,
+      const std::string& error)> ListScannersResultsCallback;
+
+  // Ownership of |results| is passed to the callback.
+  typedef base::Callback<void(
+      scoped_ptr<base::ListValue> results,
+      const std::string& error)> ScanResultsCallback;
+
+  DocumentScanInterface() {}
+  virtual ~DocumentScanInterface() {}
+
+  virtual void Scan(const std::string& scanner_name,
+                    ScanMode mode,
+                    int resolution_dpi,
+                    const ScanResultsCallback& callback) = 0;
+  virtual void ListScanners(const ListScannersResultsCallback& callback) = 0;
+};
+
+class DocumentScanScanFunction : public AsyncApiFunction {

[mef, 2014/10/13 15:59:54]

suggest: put this class into document_scan_[scan_]function.h

[Paul Stewart, 2014/10/14 19:28:31]

Because of how the API references are generated, I think this really needs to be
document_scan_api.h?

+ public:
+  DECLARE_EXTENSION_FUNCTION("documentScan.scan",
+                             DOCUMENT_SCAN_SCAN)
+  DocumentScanScanFunction();

[mef, 2014/10/13 15:59:54]

Any particular reason to call it 'ScanScan'?

[Paul Stewart, 2014/10/14 19:28:31]

It is a little unfortunate but "DocumentScan" refers to the
JavaScript interface, and "Scan" refers to the method.  It would
seem a little rash to call the JavaScript interface "Document".

+
+ protected:
+  ~DocumentScanScanFunction();
+
+  // AsyncApiFunction:
+  virtual bool Prepare() OVERRIDE;
+  virtual void AsyncWorkStart() OVERRIDE;
+  virtual bool Respond() OVERRIDE;
+
+ private:
+  void OnScannerListReceived(
+      const std::vector<DocumentScanInterface::ScannerDescription>&
+          scanner_descriptions,
+      const std::string& error);
+  void OnResultsReceived(scoped_ptr<base::ListValue> results,
+                         const std::string &error);
+
+  scoped_ptr<document_scan::Scan::Params> params_;
+  scoped_ptr<DocumentScanInterface> document_scan_interface_;
+
+  DISALLOW_COPY_AND_ASSIGN(DocumentScanScanFunction);
+};
+
+}  // namespace api
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_DOCUMENT_SCAN_DOCUMENT_SCAN_API_H_