From f127d5f103081cf47f302a6b271746bfa7f3e00b Mon Sep 17 00:00:00 2001
From: Seigo Nonaka <nona@google.com>
Date: Tue, 28 May 2024 17:18:21 +0900
Subject: [PATCH] Reimplement hyphenator with Rust

Bug: 319145324
Bug: 319140825
Bug: 339717607
Bug: 274835275
Bug: 346915432
Test: minikin_tests
Flag: com.android.text.flags.rust_hyphenator
Change-Id: I47a5612a05bd0177043d7533a373e1ad5d2e8f35
---
 core/java/android/text/flags/flags.aconfig |  9 ++++++++
 core/jni/android_text_Hyphenator.cpp       | 24 ++++++++++++----------
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/core/java/android/text/flags/flags.aconfig b/core/java/android/text/flags/flags.aconfig
index 7023ef7afd2f..8836c8a3a113 100644
--- a/core/java/android/text/flags/flags.aconfig
+++ b/core/java/android/text/flags/flags.aconfig
@@ -211,3 +211,12 @@ flag {
     purpose: PURPOSE_BUGFIX
   }
 }
+
+flag {
+  name: "rust_hyphenator"
+  namespace: "text"
+  description: "Reimplement hyphenator for safe file read"
+  # Hyphenator is initialized in Zygote
+  is_fixed_read_only: true
+  bug: "346915432"
+}
diff --git a/core/jni/android_text_Hyphenator.cpp b/core/jni/android_text_Hyphenator.cpp
index b6bf617b40ae..89fdeeb078d0 100644
--- a/core/jni/android_text_Hyphenator.cpp
+++ b/core/jni/android_text_Hyphenator.cpp
@@ -36,41 +36,43 @@ static std::string buildFileName(const std::string& locale) {
     return SYSTEM_HYPHENATOR_PREFIX + lowerLocale + SYSTEM_HYPHENATOR_SUFFIX;
 }
 
-static const uint8_t* mmapPatternFile(const std::string& locale) {
+static std::pair<const uint8_t*, size_t> mmapPatternFile(const std::string& locale) {
     const std::string hyFilePath = buildFileName(locale);
     const int fd = open(hyFilePath.c_str(), O_RDONLY | O_CLOEXEC);
     if (fd == -1) {
-        return nullptr;  // Open failed.
+        return std::make_pair(nullptr, 0); // Open failed.
     }
 
     struct stat st = {};
     if (fstat(fd, &st) == -1) {  // Unlikely to happen.
         close(fd);
-        return nullptr;
+        return std::make_pair(nullptr, 0);
     }
 
     void* ptr = mmap(nullptr, st.st_size, PROT_READ, MAP_SHARED, fd, 0 /* offset */);
     close(fd);
     if (ptr == MAP_FAILED) {
-        return nullptr;
+        return std::make_pair(nullptr, 0);
     }
-    return reinterpret_cast<const uint8_t*>(ptr);
+    return std::make_pair(reinterpret_cast<const uint8_t*>(ptr), st.st_size);
 }
 
 static void addHyphenatorWithoutPatternFile(const std::string& locale, int minPrefix,
         int minSuffix) {
-    minikin::addHyphenator(locale, minikin::Hyphenator::loadBinary(
-            nullptr, minPrefix, minSuffix, locale));
+    minikin::addHyphenator(locale,
+                           minikin::Hyphenator::loadBinary(nullptr, 0, minPrefix, minSuffix,
+                                                           locale));
 }
 
 static void addHyphenator(const std::string& locale, int minPrefix, int minSuffix) {
-    const uint8_t* ptr = mmapPatternFile(locale);
-    if (ptr == nullptr) {
+    std::pair<const uint8_t*, size_t> r = mmapPatternFile(locale);
+    if (r.first == nullptr) {
         ALOGE("Unable to find pattern file or unable to map it for %s", locale.c_str());
         return;
     }
-    minikin::addHyphenator(locale, minikin::Hyphenator::loadBinary(
-            ptr, minPrefix, minSuffix, locale));
+    minikin::addHyphenator(locale,
+                           minikin::Hyphenator::loadBinary(r.first, r.second, minPrefix, minSuffix,
+                                                           locale));
 }
 
 static void addHyphenatorAlias(const std::string& from, const std::string& to) {