[incubator-annotator] branch faster-describeTextQuote updated: Inline helper function

[gerben]

This is an automated email from the ASF dual-hosted git repository.

gerben pushed a commit to branch faster-describeTextQuote
in repository https://gitbox.apache.org/repos/asf/incubator-annotator.git


The following commit(s) were added to refs/heads/faster-describeTextQuote by 
this push:
     new 8300e73  Inline helper function
8300e73 is described below

commit 8300e738b4e719562687ae005c4cfa1817f41990
Author: Gerben <ger...@treora.com>
AuthorDate: Fri Sep 18 16:09:25 2020 +0200

    Inline helper function
---
 packages/dom/src/text-quote/describe.ts | 44 +++++++++++----------------------
 1 file changed, 15 insertions(+), 29 deletions(-)

diff --git a/packages/dom/src/text-quote/describe.ts 
b/packages/dom/src/text-quote/describe.ts
index 50a5653..0103cab 100644
--- a/packages/dom/src/text-quote/describe.ts
+++ b/packages/dom/src/text-quote/describe.ts
@@ -74,21 +74,21 @@ function calculateContextForDisambiguation(
     // Skip the found match if it is the actual target.
     if (matchStartIndex === targetStartIndex) continue;
 
-    // Count how many characters before & after them the false match and 
target have in common.
-    const sufficientPrefixLength = charactersNeededToBeUnique(
-      scopeText,
-      targetStartIndex,
-      matchStartIndex,
-      true,
-      prefix.length,
-    );
-    const sufficientSuffixLength = charactersNeededToBeUnique(
-      scopeText,
-      targetEndIndex,
-      matchEndIndex,
-      false,
-      suffix.length,
-    );
+    // Count how many characters we’d need as a prefix to disqualify this 
match.
+    let sufficientPrefixLength = prefix.length + 1;
+    const firstChar = (offset: number) => scopeText[offset - 
sufficientPrefixLength];
+    while (firstChar(targetStartIndex) && firstChar(targetStartIndex) === 
firstChar(matchStartIndex))
+      sufficientPrefixLength++;
+    if (!firstChar(targetStartIndex)) // We reached the start of scopeText; 
prefix won’t work.
+      sufficientPrefixLength = Infinity;
+
+    // Count how many characters we’d need as a suffix to disqualify this 
match.
+    let sufficientSuffixLength = suffix.length + 1;
+    const lastChar = (offset: number) => scopeText[offset + 
sufficientSuffixLength - 1];
+    while (lastChar(targetEndIndex) && lastChar(targetEndIndex) === 
lastChar(matchEndIndex))
+      sufficientSuffixLength++;
+    if (!lastChar(targetEndIndex)) // We reached the end of scopeText; suffix 
won’t work.
+      sufficientSuffixLength = Infinity;
 
     // Use either the prefix or suffix, whichever is shortest.
     if (sufficientPrefixLength <= sufficientSuffixLength) {
@@ -109,20 +109,6 @@ function calculateContextForDisambiguation(
   return { prefix, suffix };
 }
 
-function charactersNeededToBeUnique(
-  text: string,
-  target: number,
-  impostor: number,
-  reverse = false,
-  overlap = 0,
-): number {
-  const nextChar = (offset: number) => reverse ? text[offset - 1 - overlap] : 
text[offset + overlap];
-  while (nextChar(target) && nextChar(target) === nextChar(impostor))
-    overlap++;
-  if (!nextChar(target)) return Infinity; // end/start of string reached.
-  else return overlap + 1;
-}
-
 // Get the index of the first character of range within the text of scope.
 function getRangeTextPosition(range: Range, scope: Range): number {
   const iter = ownerDocument(scope).createNodeIterator(