Add find file class to search for files

Scan a folder for a file based on file name. First scan the files
in the current path, then search real directories and finally
search symlinks in that order. Goal is to locate important sysfs
files for things like brightness, battery capacity, lun files, etc

This implementation just scans for the brightness file for the LCD

Change-Id: I8ed3e74a2e2851d58b443718b6e92b50a5491f08

Android.mk

@@ -22,6 +22,7 @@ LOCAL_SRC_FILES := \
     twrpTar.cpp \
 	twrpDU.cpp \
     twrpDigest.cpp \
+    find_file.cpp
 
 LOCAL_SRC_FILES += \
     data.cpp \

data.cpp

@@ -45,6 +45,7 @@
 #ifndef TW_NO_SCREEN_TIMEOUT
 #include "gui/blanktimer.hpp"
 #endif
+#include "find_file.hpp"
 
 #ifdef TW_USE_MODEL_HARDWARE_ID_FOR_DEVICE_ID
 	#include "cutils/properties.h"
@@ -940,17 +941,31 @@ void DataManager::SetDefaultValues()
 #ifndef TW_MAX_BRIGHTNESS
 #define TW_MAX_BRIGHTNESS 255
 #endif
+	string findbright;
 	if (strcmp(EXPAND(TW_BRIGHTNESS_PATH), "/nobrightness") != 0) {
-		LOGINFO("TW_BRIGHTNESS_PATH := %s\n", EXPAND(TW_BRIGHTNESS_PATH));
+		findbright = EXPAND(TW_BRIGHTNESS_PATH);
+		LOGINFO("TW_BRIGHTNESS_PATH := %s\n", findbright.c_str());
+		if (!TWFunc::Path_Exists(findbright)) {
+			LOGINFO("Specified brightness file '%s' not found.\n", findbright.c_str());
+			findbright = "";
+		}
+	}
+	if (findbright.empty()) {
+		// Attempt to locate the brightness file
+		findbright = Find_File::Find("brightness", "/sys/class/backlight");
+	}
+	if (findbright.empty()) {
+		LOGINFO("Unable to locate brightness file\n");
+		mConstValues.insert(make_pair("tw_has_brightnesss_file", "0"));
+	} else {
+		LOGINFO("Found brightness file at '%s'\n", findbright.c_str());
 		mConstValues.insert(make_pair("tw_has_brightnesss_file", "1"));
-		mConstValues.insert(make_pair("tw_brightness_file", EXPAND(TW_BRIGHTNESS_PATH)));
+		mConstValues.insert(make_pair("tw_brightness_file", findbright));
 		ostringstream maxVal;
 		maxVal << TW_MAX_BRIGHTNESS;
 		mConstValues.insert(make_pair("tw_brightness_max", maxVal.str()));
 		mValues.insert(make_pair("tw_brightness", make_pair(maxVal.str(), 1)));
 		mValues.insert(make_pair("tw_brightness_pct", make_pair("100", 1)));
-	} else {
-		mConstValues.insert(make_pair("tw_has_brightnesss_file", "0"));
 	}
 #endif
 	mValues.insert(make_pair(TW_MILITARY_TIME, make_pair("0", 1)));

find_file.cpp

@@ -0,0 +1,89 @@
+/*
+		Copyright 2014 TeamWin
+		This file is part of TWRP/TeamWin Recovery Project.
+
+		TWRP is free software: you can redistribute it and/or modify
+		it under the terms of the GNU General Public License as published by
+		the Free Software Foundation, either version 3 of the License, or
+		(at your option) any later version.
+
+		TWRP is distributed in the hope that it will be useful,
+		but WITHOUT ANY WARRANTY; without even the implied warranty of
+		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+		GNU General Public License for more details.
+
+		You should have received a copy of the GNU General Public License
+		along with TWRP.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <string>
+#include <vector>
+#include <dirent.h>
+#include "find_file.hpp"
+#include "twrp-functions.hpp"
+#include "twcommon.h"
+
+using namespace std;
+
+string Find_File::Find(const string& file_name, const string& start_path) {
+	return Find_File().Find_Internal(file_name, start_path);
+}
+
+Find_File::Find_File() {
+}
+
+string Find_File::Find_Internal(const string& filename, const string& starting_path) {
+	DIR *d = opendir(starting_path.c_str());
+	string new_path, return_path;
+	vector<string> dirs;
+	vector<string> symlinks;
+	unsigned index;
+
+	// Check to see if we have already searched this directory to prevent infinite loops
+	if (std::find(searched_dirs.begin(), searched_dirs.end(), starting_path) != searched_dirs.end()) {
+		return "";
+	}
+	searched_dirs.push_back(starting_path);
+
+	if (d == NULL) {
+		LOGERR("Find_File: Error opening '%s'\n", starting_path.c_str());
+		return "";
+	}
+
+	struct dirent *p;
+	while ((p = readdir(d))) {
+		if (!strcmp(p->d_name, ".") || !strcmp(p->d_name, ".."))
+			continue;
+		new_path = starting_path + "/";
+		new_path.append(p->d_name);
+		if (p->d_type == DT_DIR) {
+			// Add dir to search list for later
+			dirs.push_back(new_path);
+		} else if (p->d_type == DT_LNK) {
+			// Add symlink to search list for later
+			symlinks.push_back(new_path);
+		} else if (p->d_type == DT_REG && filename == p->d_name) {
+			// We found a match!
+			closedir(d);
+			return new_path;
+		}
+	}
+	closedir(d);
+
+	// Scan real directories first if no match found in this path
+	for (index = 0; index < dirs.size(); index++) {
+		return_path = Find_Internal(filename, dirs.at(index));
+		if (!return_path.empty()) return return_path;
+	}
+	// Scan symlinks after scanning real directories
+	for (index = 0; index < symlinks.size(); index++) {
+		char buf[PATH_MAX];
+		// Resolve symlink to a real path
+		char* ret = realpath(symlinks.at(index).c_str(), buf);
+		if (ret) {
+			return_path = Find_Internal(filename, buf);
+			if (!return_path.empty()) return return_path;
+		}
+	}
+	return "";
+}

find_file.hpp

@@ -0,0 +1,37 @@
+/*
+        Copyright 2014 TeamWin
+        This file is part of TWRP/TeamWin Recovery Project.
+
+        TWRP is free software: you can redistribute it and/or modify
+        it under the terms of the GNU General Public License as published by
+        the Free Software Foundation, either version 3 of the License, or
+        (at your option) any later version.
+
+        TWRP is distributed in the hope that it will be useful,
+        but WITHOUT ANY WARRANTY; without even the implied warranty of
+        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+        GNU General Public License for more details.
+
+        You should have received a copy of the GNU General Public License
+        along with TWRP.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef Find_File_HPP
+#define Find_File_HPP
+
+#include <string>
+#include <vector>
+
+using namespace std;
+
+class Find_File {
+
+public:
+	static string Find(const string& file_name, const string& start_path);
+private:
+	Find_File();
+	string Find_Internal(const string& filename, const string& starting_path);
+	vector<string> searched_dirs;
+};
+
+#endif