Merge branch '4789-incremental-rollout-squashed' into 'master'

- The contents should be read as: Upgrades from major version 9 to major version 9 and to major version 10 are allowed. Upgrades from major version 10 to major version 10 and to major version 11 are allowed.

- Current version is always available as an upgrade (if a more recent build is found), even if file is not available (for backwards compatibility too).

## How to set incremental rollout percentage in build config file

- You can specify incremental rollout rules by adding values in `config.json` file. You can add the file only if you want percentage incremental rollout for a build.

- The format of file name will be : `<BUILD_NAME>.zip.config.json`

```shell

$ cd builds/full/test/guacamoleb/

$ tree

.

├── e.x.xx-xxyyzz-guacamoleb.zip # the full ROM zip file

└── e.x.xx-xxyyzz-guacamoleb.zip.config.json # the ROM build.config.json file

```

- E.g. : Suppose builds for "guacamoleb" devices are stored at "/mnt/rom/builds/full/test/guacamoleb". The file "/mnt/rom/builds/full/test/guacamoleb/e.x.xx-xxyyzz-guacamoleb.zip.config.json" should then have contents like:

```json

    { 

        "rollout": {

            "percentage": 20

        }   

    }

```

- The `percentage` value must be between 0 to 100. Do not add `%` sign after the value. 

- The `config.json` file is not mandatory. In case it does not exist, a build will consider a 100% rollout percentage.

### ONLY for LineageOS 15.x and newer

If you are willing to use this project on top of your LineageOS 15.x ( or newer ) ROM builds, you may have noticed that the file named `build.prop` have been removed inside your ZIP file, and has been instead integrated within your `system.new.dat` file, which is basically an ext4 image ( you can find out more here: https://source.android.com/devices/tech/ota/block ).

                  );

                  Flight::json($ret);

            });

        }

        private $incremental = '';

        private $filePath = '';

        private $buildProp = '';

        private $confProp = '';

        private $uid = null;

        private $size = '';

        private $logger = null;

            // - builds/CURRENT_ZIP_FILE.zip/system/build.prop

            // - builds/CURRENT_ZIP_FILE.zip.prop ( which must exist )

            $this->buildProp = explode("\n", @file_get_contents($this->getPropFilePath()));

            $this->confProp = $this->getConfProp();

            // Try to fetch build.prop values. In some cases, we can provide a fallback, in other a null value will be given

            $this->timestamp = intval($this->getBuildPropValue('ro.build.date.utc') ?? filemtime($this->filePath));

            $this->incremental = $this->getBuildPropValue('ro.build.version.incremental') ?? '';

        {

            return is_callable($func) && false === stripos(ini_get('disable_functions'), $func);

        }

        /**

         * Check if the current build is valid with multiple conditions

         * @param type $params The params dictionary inside the current POST request

         * @return boolean True if valid, False if not.

         */

        public function includeInResults($params)

        {

            return $this->isValid($params) && $this->checkRollout();

        }

        /**

         * Return the correct config file path (depending of version)

         * @return string

         */

        private function getConfigFilePath()

        {

            return file_exists($this->filePath . '.config.json') ? $this->filePath . '.config.json' : '';

        }

        /**

         * Return the all values from config file path

         * @return JSON if valid otherwise null

         */

        private function getConfProp(){

            $configFilePath = $this->getConfigFilePath();

            return ($configFilePath) ?  json_decode( file_get_contents($configFilePath) , true) : array();

        }

        /**

         * Return if rollout successful or not for a build

         * @return boolean

         */

        public function checkRollout()

        {

            $rolloutpercentage = isset($this->confProp['rollout']['percentage']) ? $this->confProp['rollout']['percentage'] : 100;

            if ($rolloutpercentage >= 0 && $rolloutpercentage < 100) {

                $rand_number = rand(0, 100);

                if ($rand_number > $rolloutpercentage) {

                    return false;

                }

            }

            return true;

        }

    }

 No newline at end of file

                            $build = new Build($file, $dir, $this->logger);

                        }

                        if ($build->isValid($this->postData['params'])) {

                        if ($build->includeInResults($this->postData['params'])) {

                            array_push($this->builds, $build);

                            if (!empty($this->postData['params']) && strcmp($this->postData['params']['source_incremental'], $build->getIncremental()) == 0) {

                                $this->currentBuild = $build;