[iOS] Upstream ios/chrome/browser/find_in_page

ios/chrome/browser/find_in_page/js_findinpage_manager.mm

+// Copyright 2012 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.
+
+#import "ios/chrome/browser/find_in_page/js_findinpage_manager.h"
+
+#include <string>
+
+#import "base/ios/weak_nsobject.h"
+#include "base/json/json_reader.h"
+#include "base/json/string_escape.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/sys_string_conversions.h"
+#include "base/values.h"
+#import "ios/chrome/browser/find_in_page/find_in_page_model.h"
+#import "ios/web/public/web_state/js/crw_js_early_script_manager.h"
+
+namespace {
+
+// Global variable defined in find_in_page.js that can be used for testing
+// whether JavaScript bas heen loaded.
+NSString* const kFindInPageBeacon = @"window.__gCrWeb.findInPage";
+
+// Initializes Find In Page JavaScript with the width and height of the window.
+NSString* const kFindInPageInit = @"window.__gCrWeb.findInPage && "
+                                   "window.__gCrWeb.findInPage.init(%.f, %.f);";
+
+// This will only do verbatim matches.
+// The timeout of 100ms is hardcoded into this string so we don't have
+// to spend any time at runtime to format this constant into another constant.
+NSString* const kFindInPageVerbatim =
+    @"window.__gCrWeb.findInPage && "
+     "window.__gCrWeb.findInPage.highlightWord(%@, false, 100.0);";
+
+// The timeout of 100ms is hardcoded into this string so we don't have
+// to spend any time at runtime to format this constant into another constant.
+NSString* const kFindInPagePump =
+    @"window.__gCrWeb.findInPage && "
+     "window.__gCrWeb.findInPage.pumpSearch(100.0);";
+
+NSString* const kFindInPagePrev = @"window.__gCrWeb.findInPage && "
+                                   "window.__gCrWeb.findInPage.goPrev();";
+
+NSString* const kFindInPageNext = @"window.__gCrWeb.findInPage && "
+                                   "window.__gCrWeb.findInPage.goNext();";
+
+NSString* const kFindInPageDisable = @"window.__gCrWeb.findInPage && "
+                                      "window.__gCrWeb.findInPage.disable();";
+
+NSString* const kFindInPagePending = @"[false]";
+
+const FindInPageEntry kFindInPageEntryZero = {{0.0, 0.0}, 0};
+
+}  // namespace
+
+@interface JsFindinpageManager ()
+// Update find in page model with results, return true if fip completes or
+// false if still pending and requires pumping. If |point| is not nil, it will
+// contain the scroll position upon return.
+- (BOOL)processFindInPageResult:(NSString*)result
+                 scrollPosition:(CGPoint*)point;
+// Updates find in page model with results. Calls |completionHandler| with the
+// the result of the processing and the new scroll position if successfull. If
+// |completionHandler| is called with NO, further pumping is required.
+// |completionHandler| cannot be nil.
+- (void)processFindInPagePumpResult:(NSString*)result
+                  completionHandler:(void (^)(BOOL, CGPoint))completionHandler;
+// Helper functions to extract FindInPageEntry from JSON.
+- (FindInPageEntry)findInPageEntryForJson:(NSString*)jsonStr;
+- (FindInPageEntry)entryForListValue:(base::ListValue*)position;
+// Executes |script| which is a piece of JavaScript to move to the next or
+// previous element in the page and executes |completionHandler| after moving
+// with the new scroll position passed in.
+- (void)moveHighlightByEvaluatingJavaScript:(NSString*)script
+                          completionHandler:
+                              (void (^)(CGPoint))completionHandler;
+// Updates the current match index and its found position in the model.
+- (void)updateIndex:(NSInteger)index atPoint:(CGPoint)point;
+@end
+
+@implementation JsFindinpageManager
+
+- (FindInPageModel*)findInPageModel {
+  if (!findInPageModel_)
+    findInPageModel_.reset([[FindInPageModel alloc] init]);
+  return findInPageModel_.get();
+}
+
+- (void)setWidth:(CGFloat)width height:(CGFloat)height {
+  NSString* javaScript =
+      [NSString stringWithFormat:kFindInPageInit, width, height];
+  [self evaluate:javaScript stringResultHandler:nil];
+}
+
+- (void)findString:(NSString*)query
+    completionHandler:(void (^)(BOOL, CGPoint))completionHandler {
+  DCHECK(completionHandler);
+  // Save the query in the model before searching.
+  [findInPageModel_ updateQuery:query matches:0];
+
+  // Escape |query| before passing to js.
+  std::string escapedJson;
+  base::EscapeJSONString(base::SysNSStringToUTF16(query), true, &escapedJson);
+  NSString* jsonQuery =
+      [NSString stringWithFormat:kFindInPageVerbatim,
+                                 base::SysUTF8ToNSString(escapedJson.c_str())];
+  base::WeakNSObject<JsFindinpageManager> weakSelf(self);
+  [self evaluate:jsonQuery
+      stringResultHandler:^(NSString* result, NSError* error) {
+        [weakSelf processFindInPagePumpResult:result
+                            completionHandler:completionHandler];
+      }];
+}
+
+- (void)pumpWithCompletionHandler:(void (^)(BOOL, CGPoint))completionHandler {
+  DCHECK(completionHandler);
+  base::WeakNSObject<JsFindinpageManager> weakSelf(self);
+  [self evaluate:kFindInPagePump
+      stringResultHandler:^(NSString* result, NSError* error) {
+        // TODO(shreyasv): What to do here if this returns an NSError in the
+        // WKWebView version.
+        [weakSelf processFindInPagePumpResult:result
+                            completionHandler:completionHandler];
+      }];
+}
+
+- (void)nextMatchWithCompletionHandler:(void (^)(CGPoint))completionHandler {
+  [self moveHighlightByEvaluatingJavaScript:kFindInPageNext
+                          completionHandler:completionHandler];
+}
+
+- (void)previousMatchWithCompletionHandler:
+        (void (^)(CGPoint))completionHandler {
+  [self moveHighlightByEvaluatingJavaScript:kFindInPagePrev
+                          completionHandler:completionHandler];
+}
+
+- (void)moveHighlightByEvaluatingJavaScript:(NSString*)script
+                          completionHandler:
+                              (void (^)(CGPoint))completionHandler {
+  base::WeakNSObject<JsFindinpageManager> weakSelf(self);
+  [self evaluate:script
+      stringResultHandler:^(NSString* result, NSError* error) {
+        base::WeakNSObject<JsFindinpageManager> strongSelf([weakSelf retain]);
+        if (!strongSelf)
+          return;
+        DCHECK(!error);
+        FindInPageEntry entry = kFindInPageEntryZero;
+        if (![result isEqualToString:kFindInPagePending])
+          entry = [strongSelf findInPageEntryForJson:result];
+        CGPoint newPoint = entry.point;
+        [strongSelf updateIndex:entry.index atPoint:newPoint];
+        if (completionHandler)
+          completionHandler(newPoint);
+      }];
+}
+
+- (void)disableWithCompletionHandler:(ProceduralBlock)completionHandler {
+  DCHECK(completionHandler);
+  base::WeakNSObject<FindInPageModel> weakFindInPageModel(findInPageModel_);
+  [self evaluate:kFindInPageDisable
+      stringResultHandler:^(NSString* result, NSError* error) {
+        [weakFindInPageModel setEnabled:NO];
+        completionHandler();
+      }];
+}
+
+#pragma mark -
+#pragma mark FindInPageEntry
+
+- (BOOL)processFindInPageResult:(NSString*)result
+                 scrollPosition:(CGPoint*)point {
+  if (!result)
+    return NO;
+
+  // Parse JSONs.
+  std::string json([result UTF8String]);
+  scoped_ptr<base::Value> root(base::JSONReader::Read(json, false));
+  if (!root.get())
+    return YES;
+  if (!root->IsType(base::Value::TYPE_LIST))
+    return YES;
+
+  base::ListValue* resultList = static_cast<base::ListValue*>(root.get());
+  DCHECK(resultList);
+  if (resultList) {
+    if (resultList->GetSize() == 2) {
+      int numHighlighted = 0;
+      if (resultList->GetInteger(0, &numHighlighted)) {
+        if (numHighlighted > 0) {
+          base::ListValue* position;
+          if (resultList->GetList(1, &position)) {
+            [findInPageModel_ updateQuery:nil matches:numHighlighted];
+            // Scroll to first match.
+            FindInPageEntry entry = [self entryForListValue:position];
+            [findInPageModel_ updateIndex:entry.index atPoint:entry.point];
+            if (point)
+              *point = entry.point;
+          }
+        }
+      }
+    }
+  }
+  return YES;
+}
+
+- (void)processFindInPagePumpResult:(NSString*)result
+                  completionHandler:(void (^)(BOOL, CGPoint))completionHandler {
+  CGPoint point = CGPointZero;
+  if ([result isEqualToString:kFindInPagePending]) {
+    completionHandler(NO, point);
+  }
+  // TODO(shreyasv): Inline this call from the logic from the above function
+  // and remove the above function.
+  BOOL processFIPResult =
+      [self processFindInPageResult:result scrollPosition:&point];
+  completionHandler(processFIPResult, point);
+}
+
+- (void)updateIndex:(NSInteger)index atPoint:(CGPoint)point {
+  [findInPageModel_ updateIndex:index atPoint:point];
+}
+
+- (FindInPageEntry)findInPageEntryForJson:(NSString*)jsonStr {
+  std::string json([jsonStr UTF8String]);
+  scoped_ptr<base::Value> root(base::JSONReader::Read(json, false));
+  if (!root.get())
+    return kFindInPageEntryZero;
+
+  if (!root->IsType(base::Value::TYPE_LIST))
+    return kFindInPageEntryZero;
+
+  base::ListValue* position = static_cast<base::ListValue*>(root.get());
+  return [self entryForListValue:position];
+}
+
+- (FindInPageEntry)entryForListValue:(base::ListValue*)position {
+  if (!position)
+    return kFindInPageEntryZero;
+
+  // Position should always be of length 3, from [index,x,y].
+  DCHECK(position->GetSize() == 3);
+  if (position->GetSize() != 3)
+    return kFindInPageEntryZero;
+
+  // The array position comes from the JSON string [index, x, y], which
+  // represents the index of the currently found string, and the x and y
+  // position necessary to center that string.  Pull out that data into a
+  // FindInPageEntry struct.
+  int index;
+  double x = 0, y = 0;
+  position->GetInteger(0, &index);
+  position->GetDouble(1, &x);
+  position->GetDouble(2, &y);
+  FindInPageEntry entry;
+  entry.index = index;
+  entry.point.x = x;
+  entry.point.y = y;
+  return entry;
+}
+
+#pragma mark -
+#pragma mark ProtectedMethods
+
+- (NSString*)scriptPath {
+  return @"find_in_page";
+}
+
+- (NSString*)presenceBeacon {
+  return kFindInPageBeacon;
+}
+
+- (NSArray*)directDependencies {
+  return @[ [CRWJSEarlyScriptManager class] ];
+}
+
+@end