Initial commit

2018-04-15 16:41:46 +02:00
commit 86ff40274b
29 changed files with 1368 additions and 0 deletions
--- a/src/Shm/SharedData.php
+++ b/src/Shm/SharedData.php
@ -0,0 +1,133 @@
+<?php
+
+namespace NoccyLabs\Ipc\Shm;
+
+/**
+ * Shared data storage with a key-value interface
+ * 
+ */
+class SharedData extends SharedMemory
+{
+    private const IDX_LOCK = 0;
+    private const IDX_MAP = 1;
+    private const IDX_DATA = 2;
+
+    private $checks = [];
+
+    /**
+     * Acquire a lock
+     *
+     * @return void
+     */
+    private function lock()
+    {
+        $expire = microtime(true) + 1;
+        while ($this[self::IDX_LOCK] !== null) {
+            usleep(1000);
+            // Forcefully continue after 1 second
+            if (microtime(true)>$expire) {
+                break;
+            }
+        }
+        $this[self::IDX_LOCK] = 1;
+    }
+
+    /**
+     * Release the lock
+     *
+     * @return void
+     */
+    private function unlock()
+    {
+        $this[self::IDX_LOCK] = null;
+    }
+
+    /**
+     * Get the value of a key
+     *
+     * @param string $key
+     * @return mixed
+     */
+    public function get(string $key)
+    {
+        $map = (array)$this[self::IDX_MAP];
+        
+        // If the key doesn't exist, return null
+        if (!array_key_exists($key, $map)) {
+            return null;
+        }
+
+        $index = $map[$key];
+        $keyvar = $this[self::IDX_DATA + $index];
+
+        // If for some reason we don't get anything back, return null
+        if (!$keyvar) {
+            return null;
+        }
+        
+        // Save the checksum for later and return the value
+        $this->checks[$key] = $keyvar[0];
+        return $keyvar[1];
+
+    }
+
+    /**
+     * Set a key to a specific value
+     *
+     * @param string $key
+     * @param mixed $value
+     * @param boolean $check
+     * @return boolean
+     */
+    public function set(string $key, $value, $check=false):bool
+    {
+        // Acquire a lock and fetch the map
+        $this->lock();
+        $map = (array)$this[self::IDX_MAP];
+
+        // If the key doesn't exist in the map, we need to set it up
+        if (!array_key_exists($key, $map)) {
+            $free = 0;
+            // Find first free index
+            foreach ($map as $map_key=>$index) {
+                if ($index != $free) { break; }
+                $free++;
+            }
+            // Store the index in the map, and sort it by index.
+            $map[$key] = $free;
+            asort($map);
+            $this[self::IDX_MAP] = $map;
+        }
+
+        // Look up the key and fetch the data
+        $index = $map[$key];
+        $keyvar = $this[self::IDX_DATA + $index];
+
+        // Check the data to make sure the data hasn't changed since last read
+        if ($check && $keyvar && array_key_exists($key, $this->checks)) {
+            if ($keyvar[0] != $this->checks[$key]) {
+                $this->unlock();
+                return false;
+            }
+        }
+
+        // Update the data
+        $this[self::IDX_DATA + $index] = [ md5($value), $value ];
+        $this->unlock();
+        return true;
+    }
+
+    /**
+     * Check if the map contains the key. This method doesn't acquire a lock
+     *
+     * @param string $key
+     * @return bool
+     */
+    public function contains(string $key):bool
+    {
+        $map = (array)$this[self::IDX_MAP];
+
+        return array_key_exists($key, $map);
+    }
+
+}