Default share to Share Target: Partial impl. of Web Share for Desktop.

chrome/browser/webshare/share_service_impl.cc

 // Copyright 2016 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 "chrome/browser/webshare/share_service_impl.h"
 
+#include <algorithm>
+#include <functional>
+#include <utility>
+
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_commands.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/browser_tabstrip.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
+#include "net/base/escape.h"
 
 // static
 void ShareServiceImpl::Create(blink::mojom::ShareServiceRequest request) {
   mojo::MakeStrongBinding(base::MakeUnique<ShareServiceImpl>(),
                           std::move(request));
 }
 
+// static
+std::string ShareServiceImpl::ReplacePlaceholders(
+    const std::string url_template,
+    const std::string title,
+    const std::string text,
+    const GURL& share_url,
+    int* error) {
+  std::string title_escaped = net::EscapeQueryParamValue(title, false);
+  std::string text_escaped = net::EscapeQueryParamValue(text, false);
+  std::string share_url_escaped =
+      net::EscapeQueryParamValue(share_url.spec(), false);
+
+  constexpr char kTitlePlaceholder[] = "%{title}";
+  constexpr char kTextPlaceholder[] = "%{text}";
+  constexpr char kUrlPlaceholder[] = "%{url}";
+
+  std::vector<base::StringPiece> placeholders;
+  placeholders.push_back(kTitlePlaceholder);
+  placeholders.push_back(kTextPlaceholder);
+  placeholders.push_back(kUrlPlaceholder);
+
+  std::vector<base::StringPiece> share_data;
+  share_data.push_back(title_escaped);
+  share_data.push_back(text_escaped);
+  share_data.push_back(share_url_escaped);
+
+  std::map<base::StringPiece, base::StringPiece> placeholder_to_data;

[Sam McNally, 2017/01/04 09:15:46]

You could use an initializer list to initialise this:
... placeholder_to_data = {{kTitlePlaceholder, title_escaped}, ...};

[constantina, 2017/01/05 00:34:38]

I will keep it like this, in case we expand the API to allow more fields in the
shared data. I have however changed the previous 2 blocks to use initializer
lists.

+  for (unsigned long i = 0; i < placeholders.size(); ++i) {
+    placeholder_to_data[placeholders[i]] = share_data[i];
+  }
+
+  // Find open ("%{") and close ("}") identifiers, and record indices.
+  // If two opens occur before a close, or a close occurs with no preceding
+  // open, return an error code.
+  std::vector<int> placeholder_open_indices;

[Sam McNally, 2017/01/04 09:15:46]

Consider building a std::vector<base::StringPiece> of string segments to glue
together.

[constantina, 2017/01/05 00:34:38]

Acknowledged.

+  std::vector<int> placeholder_close_indices;
+  bool lastSawOpen = false;

[Sam McNally, 2017/01/04 09:15:46]

last_saw_open

[constantina, 2017/01/05 00:34:38]

Done.

+  for (unsigned long i = 0; i < url_template.size(); ++i) {

[Sam McNally, 2017/01/04 09:15:46]

size_t

[constantina, 2017/01/05 00:34:38]

Done.

+    if (url_template[i] == '%' && i < url_template.size() &&
+        url_template[i + 1] == '{') {
+      if (lastSawOpen) {
+        *error = 1;
+        return url_template;
+      }
+      lastSawOpen = true;
+      placeholder_open_indices.push_back(i);
+    } else if (url_template[i] == '}') {
+      if (!lastSawOpen) {
+        *error = 1;
+        return url_template;
+      }
+      lastSawOpen = false;
+      placeholder_close_indices.push_back(i);
+    }
+  }
+  if (lastSawOpen) {
+    *error = 1;
+    return url_template;
+  }
+
+  // Look at each placeholder, and check if it is valid.
+  // If it is, replace the placeholder with its corresponding share datum.
+  // Otherwise, replace it with an empty string.
+  std::string url_template_filled = "";

[Sam McNally, 2017/01/04 09:15:46]

The default constructor is fine. It's probably worth using reserve() though.

[constantina, 2017/01/05 00:34:38]

Done.

+  int start_index_to_copy = 0;

[Sam McNally, 2017/01/04 09:15:46]

size_t

[constantina, 2017/01/05 00:34:38]

Done.

+  for (unsigned long i = 0; i < placeholder_open_indices.size(); ++i) {
+    int placeholder_open = placeholder_open_indices[i];
+    int placeholder_close = placeholder_close_indices[i];
+
+    url_template_filled += url_template.substr(
+        start_index_to_copy, placeholder_open - start_index_to_copy);
+
+    base::StringPiece placeholder = url_template.substr(
+        placeholder_open, placeholder_close + 1 - placeholder_open);
+
+    if (placeholder_to_data.count(placeholder)) {

[Sam McNally, 2017/01/04 09:15:46]

Use placeholder_to_data.find(). This avoids a second lookup with operator[].

[constantina, 2017/01/05 00:34:38]

Done.

+      url_template_filled += placeholder_to_data[placeholder].as_string();

[Sam McNally, 2017/01/04 09:15:46]

Use placeholder_to_data[placeholder].AppendToString(&url_template_filled)

That should avoid an unnecessary copy.

[constantina, 2017/01/05 00:34:38]

Done.

+    }
+    start_index_to_copy = placeholder_close + 1;
+  }
+  url_template_filled += url_template.substr(start_index_to_copy);
+  *error = 0;
+  return url_template_filled;
+}
+
+void ShareServiceImpl::OpenTargetURL(const GURL& target_url) {
+  Browser* browser = BrowserList::GetInstance()->GetLastActive();
+  chrome::AddTabAt(browser, target_url,
+                   browser->tab_strip_model()->active_index() + 1, true);
+}
+
 void ShareServiceImpl::Share(const std::string& title,
                              const std::string& text,
-                             const GURL& url,
+                             const GURL& share_url,
                              const ShareCallback& callback) {
-  // TODO(constantina): Implement Web Share Target here.
-  NOTIMPLEMENTED();
-  callback.Run(base::Optional<std::string>("Not implemented: navigator.share"));
+  bool error_occured = false;
+
+  const char kUrlBase[] = "https://wicg.github.io/web-share-target/";
+  std::string url_template =
+      "demos/sharetarget.html?title=%{title}&text=%{text}&url=%{url}";
+
+  int error = 0;
+  std::string url_template_filled =
+      ReplacePlaceholders(url_template, title, text, share_url, &error);
+  error_occured |= error;
+
+  GURL target_url(kUrlBase + url_template_filled);
+  OpenTargetURL(target_url);
+
+  if (error_occured) {
+    callback.Run(base::Optional<std::string>("Error"));
+  } else {
+    callback.Run(base::Optional<std::string>());
+  }
 }