Files
Crosspoint/src/activities/home/MyLibraryActivity.cpp
T
Uri Tauber dc6562a51c fix: Fix a dangling pointer (#939)
## Summary

* **What is the goal of this PR?** Fix a dangling pointer issue caused
by using `.c_str()` on a temporary `std::string`.

`basepath.substr()` creates a temporary `std::string`, and calling
`.c_str()` on it returns a pointer to its internal buffer (not a copy).
Since the temporary string is destroyed at the end of the full
expression, `folderName` ends up holding a dangling pointer, leading to
undefined behavior.

To solve this, we stores the result in a persistent `std::string`
object, ensuring the underlying buffer remains valid for the duration of
its use.

A similar pattern caused the behavior reported in
https://github.com/crosspoint-reader/crosspoint-reader/pull/728#issuecomment-3902529697

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**< NO >**_
2026-02-18 11:55:23 +01:00

224 lines
6.7 KiB
C++

#include "MyLibraryActivity.h"
#include <GfxRenderer.h>
#include <HalStorage.h>
#include <I18n.h>
#include <algorithm>
#include "MappedInputManager.h"
#include "components/UITheme.h"
#include "fontIds.h"
#include "util/StringUtils.h"
namespace {
constexpr unsigned long GO_HOME_MS = 1000;
} // namespace
void sortFileList(std::vector<std::string>& strs) {
std::sort(begin(strs), end(strs), [](const std::string& str1, const std::string& str2) {
// Directories first
bool isDir1 = str1.back() == '/';
bool isDir2 = str2.back() == '/';
if (isDir1 != isDir2) return isDir1;
// Start naive natural sort
const char* s1 = str1.c_str();
const char* s2 = str2.c_str();
// Iterate while both strings have characters
while (*s1 && *s2) {
// Check if both are at the start of a number
if (isdigit(*s1) && isdigit(*s2)) {
// Skip leading zeros and track them
const char* start1 = s1;
const char* start2 = s2;
while (*s1 == '0') s1++;
while (*s2 == '0') s2++;
// Count digits to compare lengths first
int len1 = 0, len2 = 0;
while (isdigit(s1[len1])) len1++;
while (isdigit(s2[len2])) len2++;
// Different length so return smaller integer value
if (len1 != len2) return len1 < len2;
// Same length so compare digit by digit
for (int i = 0; i < len1; i++) {
if (s1[i] != s2[i]) return s1[i] < s2[i];
}
// Numbers equal so advance pointers
s1 += len1;
s2 += len2;
} else {
// Regular case-insensitive character comparison
char c1 = tolower(*s1);
char c2 = tolower(*s2);
if (c1 != c2) return c1 < c2;
s1++;
s2++;
}
}
// One string is prefix of other
return *s1 == '\0' && *s2 != '\0';
});
}
void MyLibraryActivity::loadFiles() {
files.clear();
auto root = Storage.open(basepath.c_str());
if (!root || !root.isDirectory()) {
if (root) root.close();
return;
}
root.rewindDirectory();
char name[500];
for (auto file = root.openNextFile(); file; file = root.openNextFile()) {
file.getName(name, sizeof(name));
if (name[0] == '.' || strcmp(name, "System Volume Information") == 0) {
file.close();
continue;
}
if (file.isDirectory()) {
files.emplace_back(std::string(name) + "/");
} else {
auto filename = std::string(name);
if (StringUtils::checkFileExtension(filename, ".epub") || StringUtils::checkFileExtension(filename, ".xtch") ||
StringUtils::checkFileExtension(filename, ".xtc") || StringUtils::checkFileExtension(filename, ".txt") ||
StringUtils::checkFileExtension(filename, ".md")) {
files.emplace_back(filename);
}
}
file.close();
}
root.close();
sortFileList(files);
}
void MyLibraryActivity::onEnter() {
Activity::onEnter();
loadFiles();
selectorIndex = 0;
requestUpdate();
}
void MyLibraryActivity::onExit() {
Activity::onExit();
files.clear();
}
void MyLibraryActivity::loop() {
// Long press BACK (1s+) goes to root folder
if (mappedInput.isPressed(MappedInputManager::Button::Back) && mappedInput.getHeldTime() >= GO_HOME_MS &&
basepath != "/") {
basepath = "/";
loadFiles();
selectorIndex = 0;
return;
}
const int pageItems = UITheme::getInstance().getNumberOfItemsPerPage(renderer, true, false, true, false);
if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
if (files.empty()) {
return;
}
if (basepath.back() != '/') basepath += "/";
if (files[selectorIndex].back() == '/') {
basepath += files[selectorIndex].substr(0, files[selectorIndex].length() - 1);
loadFiles();
selectorIndex = 0;
requestUpdate();
} else {
onSelectBook(basepath + files[selectorIndex]);
return;
}
}
if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
// Short press: go up one directory, or go home if at root
if (mappedInput.getHeldTime() < GO_HOME_MS) {
if (basepath != "/") {
const std::string oldPath = basepath;
basepath.replace(basepath.find_last_of('/'), std::string::npos, "");
if (basepath.empty()) basepath = "/";
loadFiles();
const auto pos = oldPath.find_last_of('/');
const std::string dirName = oldPath.substr(pos + 1) + "/";
selectorIndex = findEntry(dirName);
requestUpdate();
} else {
onGoHome();
}
}
}
int listSize = static_cast<int>(files.size());
buttonNavigator.onNextRelease([this, listSize] {
selectorIndex = ButtonNavigator::nextIndex(static_cast<int>(selectorIndex), listSize);
requestUpdate();
});
buttonNavigator.onPreviousRelease([this, listSize] {
selectorIndex = ButtonNavigator::previousIndex(static_cast<int>(selectorIndex), listSize);
requestUpdate();
});
buttonNavigator.onNextContinuous([this, listSize, pageItems] {
selectorIndex = ButtonNavigator::nextPageIndex(static_cast<int>(selectorIndex), listSize, pageItems);
requestUpdate();
});
buttonNavigator.onPreviousContinuous([this, listSize, pageItems] {
selectorIndex = ButtonNavigator::previousPageIndex(static_cast<int>(selectorIndex), listSize, pageItems);
requestUpdate();
});
}
void MyLibraryActivity::render(Activity::RenderLock&&) {
renderer.clearScreen();
const auto pageWidth = renderer.getScreenWidth();
const auto pageHeight = renderer.getScreenHeight();
auto metrics = UITheme::getInstance().getMetrics();
std::string folderName = (basepath == "/") ? tr(STR_SD_CARD) : basepath.substr(basepath.rfind('/') + 1);
GUI.drawHeader(renderer, Rect{0, metrics.topPadding, pageWidth, metrics.headerHeight}, folderName.c_str());
const int contentTop = metrics.topPadding + metrics.headerHeight + metrics.verticalSpacing;
const int contentHeight = pageHeight - contentTop - metrics.buttonHintsHeight - metrics.verticalSpacing;
if (files.empty()) {
renderer.drawText(UI_10_FONT_ID, metrics.contentSidePadding, contentTop + 20, tr(STR_NO_BOOKS_FOUND));
} else {
GUI.drawList(
renderer, Rect{0, contentTop, pageWidth, contentHeight}, files.size(), selectorIndex,
[this](int index) { return files[index]; }, nullptr, nullptr, nullptr);
}
// Help text
const auto labels = mappedInput.mapLabels(basepath == "/" ? tr(STR_HOME) : tr(STR_BACK), tr(STR_OPEN), tr(STR_DIR_UP),
tr(STR_DIR_DOWN));
GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
renderer.displayBuffer();
}
size_t MyLibraryActivity::findEntry(const std::string& name) const {
for (size_t i = 0; i < files.size(); i++)
if (files[i] == name) return i;
return 0;
}