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 "base/memory/ptr_util.h"
+#include <algorithm>
+#include <functional>
+#include <utility>
+
+#include "base/strings/string_util.h"
+#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"
+
+namespace {
+
+// Determines whether a character is allowed in a URL template placeholder.
+bool IsIdentifier(char c) {
+  return base::IsAsciiAlpha(c) || base::IsAsciiDigit(c) || c == '-' || c == '_';
+}
+
+// Joins a std::vector<base::StringPiece> into a single std::string.
+std::string JoinString(const std::vector<base::StringPiece>& pieces) {

[kenrb, 2017/01/12 14:53:37]

Is there a reason you are implementing this rather than just calling
base::JoinString? If there is a reason why the function in base isn't what you
need, it seems to warrant a comment explaining why.

[constantina, 2017/01/13 00:40:06]

It is simply because base::JoinString doesn't take a vector of StringPieces,
only a vector of Strings. I added a TODO to implement this in base.

+  size_t total_size = 0;
+  for (const auto& piece : pieces) {
+    total_size += piece.size();
+  }
+  std::string joined_pieces;
+  joined_pieces.reserve(total_size);
+
+  for (const auto& piece : pieces) {
+    piece.AppendToString(&joined_pieces);
+  }
+  return joined_pieces;
+}
+
+}  // namespace
 
 // static
 void ShareServiceImpl::Create(blink::mojom::ShareServiceRequest request) {
   mojo::MakeStrongBinding(base::MakeUnique<ShareServiceImpl>(),
                           std::move(request));
 }
 
+// static
+bool ShareServiceImpl::ReplacePlaceholders(base::StringPiece url_template,
+                                           base::StringPiece title,
+                                           base::StringPiece text,
+                                           const GURL& share_url,
+                                           std::string* url_template_filled) {
+  constexpr char kTitlePlaceholder[] = "title";
+  constexpr char kTextPlaceholder[] = "text";
+  constexpr char kUrlPlaceholder[] = "url";
+
+  std::map<base::StringPiece, std::string> placeholder_to_data;
+  placeholder_to_data[kTitlePlaceholder] =
+      net::EscapeQueryParamValue(title, false);
+  placeholder_to_data[kTextPlaceholder] =
+      net::EscapeQueryParamValue(text, false);
+  placeholder_to_data[kUrlPlaceholder] =
+      net::EscapeQueryParamValue(share_url.spec(), false);
+
+  std::vector<base::StringPiece> split_template;
+  bool last_saw_open = false;
+  size_t start_index_to_copy = 0;
+  for (size_t i = 0; i < url_template.size(); ++i) {
+    if (last_saw_open) {
+      if (url_template[i] == '}') {
+        base::StringPiece placeholder = url_template.substr(
+            start_index_to_copy + 1, i - 1 - start_index_to_copy);
+        auto it = placeholder_to_data.find(placeholder);
+        if (it != placeholder_to_data.end()) {
+          // Replace the placeholder text with the parameter value.
+          split_template.push_back(it->second);
+        }
+
+        last_saw_open = false;
+        start_index_to_copy = i + 1;
+      } else if (!IsIdentifier(url_template[i])) {
+        // Error: Non-identifier character seen after open.
+        return false;
+      }
+    } else {
+      if (url_template[i] == '}') {
+        // Error: Saw close, with no corresponding open.
+        return false;
+      } else if (url_template[i] == '{') {
+        split_template.push_back(
+            url_template.substr(start_index_to_copy, i - start_index_to_copy));
+
+        last_saw_open = true;
+        start_index_to_copy = i;
+      }
+    }
+  }
+  if (last_saw_open) {
+    // Error: Saw open that was never closed.
+    return false;
+  }
+  split_template.push_back(url_template.substr(
+      start_index_to_copy, url_template.size() - start_index_to_copy));
+
+  *url_template_filled = JoinString(split_template);
+  return true;
+}
+
+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"));
+  // TODO(constantina): replace hard-coded URL with one from user-chosen site.
+  constexpr char kUrlBase[] = "https://wicg.github.io/web-share-target/";
+  constexpr char kUrlTemplate[] =
+      "demos/sharetarget.html?title={title}&text={text}&url={url}";
+
+  std::string url_template_filled;
+  if (!ReplacePlaceholders(kUrlTemplate, title, text, share_url,
+                           &url_template_filled)) {
+    callback.Run(base::Optional<std::string>(
+        "Error: unable to replace placeholders in url template"));
+    return;
+  }
+
+  GURL target_url(kUrlBase + url_template_filled);
+  if (!target_url.is_valid()) {
+    callback.Run(base::Optional<std::string>(
+        "Error: url of share target is not a valid url."));
+    return;
+  }
+  OpenTargetURL(target_url);
+
+  callback.Run(base::nullopt);
 }