IVGCVSW-3541 Get the paths where to load the dynamic backends from

 * Adds GetBackendPaths and IsPathValid to DynamicBackendUtils
 * Adds related unit tests

Change-Id: I94e377d92a88a4b5d48026f6ad5b4d5387d20c21
Signed-off-by: Jan Eilers <jan.eilers@arm.com>
Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>

1 files changed, 92 insertions, 0 deletions

diff --git a/src/backends/backendsCommon/DynamicBackendUtils.cpp b/src/backends/backendsCommon/DynamicBackendUtils.cpp
index 0ab02d7c98..ae36a24b30 100644
--- a/src/backends/backendsCommon/DynamicBackendUtils.cpp
+++ b/src/backends/backendsCommon/DynamicBackendUtils.cpp
@@ -5,6 +5,10 @@
 
 #include "DynamicBackendUtils.hpp"
 
+#include <boost/filesystem/operations.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/log/trivial.hpp>
+
 namespace armnn
 {
 
@@ -59,4 +63,92 @@ std::string DynamicBackendUtils::GetDlError()
     return std::string(errorMessage);
 }
 
+std::vector<std::string> DynamicBackendUtils::GetBackendPaths(const std::string& overrideBackendPath)
+{
+    // Check if a path where to dynamically load the backends from is given
+    if (!overrideBackendPath.empty())
+    {
+        if (!IsPathValid(overrideBackendPath))
+        {
+            BOOST_LOG_TRIVIAL(warning) << "WARNING: The given override path for dynamic backends \""
+                                       << overrideBackendPath << "\" is not valid";
+
+            return {};
+        }
+
+        return std::vector<std::string>{ overrideBackendPath };
+    }
+
+    // Expects a colon-separated list: DYNAMIC_BACKEND_PATHS="PATH_1:PATH_2:...:PATH_N"
+    const std::string backendPaths = DYNAMIC_BACKEND_PATHS;
+
+    return GetBackendPathsImpl(backendPaths);
+}
+
+std::vector<std::string> DynamicBackendUtils::GetBackendPathsImpl(const std::string& backendPaths)
+{
+    std::unordered_set<std::string> uniqueBackendPaths;
+    std::vector<std::string> tempBackendPaths;
+    std::vector<std::string> validBackendPaths;
+
+    // Split the given list of paths
+    boost::split(tempBackendPaths, backendPaths, boost::is_any_of(":"));
+
+    for (const std::string& path : tempBackendPaths)
+    {
+        // Check whether the path is valid
+        if (!IsPathValid(path))
+        {
+            continue;
+        }
+
+        // Check whether the path is a duplicate
+        auto it = uniqueBackendPaths.find(path);
+        if (it != uniqueBackendPaths.end())
+        {
+            // The path is a duplicate
+            continue;
+        }
+
+        // Add the path to the set of unique paths
+        uniqueBackendPaths.insert(path);
+
+        // Add the path to the list of valid paths
+        validBackendPaths.push_back(path);
+    }
+
+    return validBackendPaths;
+}
+
+bool DynamicBackendUtils::IsPathValid(const std::string& path)
+{
+    if (path.empty())
+    {
+        BOOST_LOG_TRIVIAL(warning) << "WARNING: The given backend path is empty";
+        return false;
+    }
+
+    boost::filesystem::path boostPath(path);
+
+    if (!boost::filesystem::exists(boostPath))
+    {
+        BOOST_LOG_TRIVIAL(warning) << "WARNING: The given backend path \"" << path << "\" does not exist";
+        return false;
+    }
+
+    if (!boost::filesystem::is_directory(boostPath))
+    {
+        BOOST_LOG_TRIVIAL(warning) << "WARNING: The given backend path \"" << path << "\" is not a directory";
+        return false;
+    }
+
+    if (!boostPath.is_absolute())
+    {
+        BOOST_LOG_TRIVIAL(warning) << "WARNING: The given backend path \"" << path << "\" is not absolute";
+        return false;
+    }
+
+    return true;
+}
+
 } // namespace armnn