Handle CPS_PATH and CPS_PREFIX_PATH according to the current spec

Where CPS_PATH behaves more like PKG_CONFIG_PATH (which is what we were
already doing, incorrectly), and CPS_PREFIX_PATH has been added, and
acts more like CMAKE_PREFIX_PATH

meson.build

@@ -42,7 +42,7 @@ foreach t : [['cps integration tests', 'cps-config.toml'], ['pkg-config compatib
     python_interpreter,
     args: [files('tests/runner.py'), cps_config, 'tests/cases/' + t[1]],
     protocol : 'tap',
-    env : {'CPS_PATH' : meson.current_source_dir() / 'tests' / 'cps-files' },
+    env : {'CPS_PREFIX_PATH' : meson.current_source_dir() / 'tests' / 'cps-files' },
   )
 endforeach
 

src/cps/env.cpp

@@ -14,6 +14,9 @@ namespace cps {
         if (const char * env_c = std::getenv("CPS_PATH")) {
             env.cps_path = std::string(env_c);
         }
+        if (const char * env_c = std::getenv("CPS_PREFIX_PATH")) {
+            env.cps_prefix_path = std::string(env_c);
+        }
         if (std::getenv("PKG_CONFIG_DEBUG_SPEW") || std::getenv("CPS_CONFIG_DEBUG_SPEW")) {
             env.debug_spew = true;
         }

src/cps/env.hpp

@@ -11,6 +11,7 @@ namespace cps {
 
     struct Env {
         std::optional<std::string> cps_path = std::nullopt;
+        std::optional<std::string> cps_prefix_path = std::nullopt;
         bool debug_spew = false;
     };
 

src/cps/search.cpp

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 // Copyright © 2023-2024 Dylan Baker
-// Copyright © 2024 Bret Brown
+// Copyright © 2024 Dylan Baker
 
 #include "cps/search.hpp"
 
@@ -71,38 +71,73 @@ namespace cps::search {
             return out;
         }
 
-        const std::vector<fs::path> nix{"/usr", "/usr/local"};
-        // TODO: const std::vector<std::string> mac{""};
-        // TODO: const std::vector<std::string> win{""};
+        fs::path libdir() {
+            // TODO: libdir needs to be configurable based on the personality,
+            //       and different name schemes.
+            //       This is complicated by the fact that different distros have
+            //       different schemes.
+            return "lib";
+        }
+
+        fs::path datadir() {
+            // TODO: needs to be configurable. see libdir above.
+            return "share";
+        }
+
+        const std::vector<fs::path> nix_prefix{"/usr", "/usr/local"};
+        // TODO: const std::vector<std::string> mac_prefix{""};
+        // TODO: const std::vector<std::string> win_prefix{""};
 
         std::vector<fs::path> cached_paths{};
 
-        const std::vector<fs::path> search_paths(Env env) {
+        /// @brief expands a single search prefix into a set of full paths
+        /// @param prefix the prefix to build from
+        /// @return A vector of paths to search, in order
+        std::vector<fs::path> expand_prefix(const fs::path & prefix) {
+            std::vector<fs::path> paths{};
+
+            // TODO: macOS specific paths
+            // TODO: Windows specific paths
+
+            // TODO: handle name-like search paths
+            paths.emplace_back(prefix / libdir() / "cps");
+            paths.emplace_back(prefix / datadir() / "cps");
+
+            return paths;
+        };
+
+        /// @brief Expands CPS search prefixes into concrete paths
+        /// @param env stored environment variables
+        /// @return A vector of paths to search, in order
+        const std::vector<fs::path> search_paths(const Env & env) {
             if (!cached_paths.empty()) {
                 return cached_paths;
             }
 
             if (env.cps_path) {
-                cached_paths.reserve(nix.size());
-                cached_paths.insert(cached_paths.end(), nix.begin(), nix.end());
                 auto && paths = utils::split(env.cps_path.value());
+                cached_paths.reserve(paths.size());
+                cached_paths.insert(cached_paths.end(), paths.begin(), paths.end());
+            }
+
+            if (env.cps_prefix_path) {
+                auto && prefixes = utils::split(env.cps_prefix_path.value());
+                for (auto && p : prefixes) {
+                    auto && paths = expand_prefix(p);
+                    cached_paths.reserve(cached_paths.size() + paths.size());
+                    cached_paths.insert(cached_paths.end(), paths.begin(), paths.end());
+                }
+            }
+
+            for (auto && p : nix_prefix) {
+                auto && paths = expand_prefix(p);
                 cached_paths.reserve(cached_paths.size() + paths.size());
                 cached_paths.insert(cached_paths.end(), paths.begin(), paths.end());
-            } else {
-                cached_paths = nix;
             }
 
             return cached_paths;
         }
 
-        const fs::path libdir() {
-            // TODO: libdir needs to be configurable based on the personality,
-            //       and different name schemes.
-            //       This is complicated by the fact that different distros have
-            //       different schemes.
-            return "lib";
-        }
-
         /// @brief Find all possible paths for a given CPS name
         /// @param name The name of the CPS file to find
         /// @return A vector of paths which patch the given name, or an error
@@ -119,15 +154,10 @@ namespace cps::search {
             // dependency?
             auto && paths = search_paths(env);
             std::vector<fs::path> found{};
-            for (auto && prefix : paths) {
-                // TODO: <prefix>/<libdir>/cps/<name-like>/
-                // TODO: <prefix>/share/cps/<name-like>/
-                // TODO: <prefix>/share/cps/
-
-                const fs::path dir = prefix / libdir() / "cps";
-                if (fs::is_directory(dir)) {
+            for (auto && path : paths) {
+                if (fs::is_directory(path)) {
                     // TODO: <name-like>
-                    const fs::path file = dir / fmt::format("{}.cps", name);
+                    const fs::path file = path / fmt::format("{}.cps", name);
                     if (fs::is_regular_file(file)) {
                         found.push_back(file);
                     }

tests/CMakeLists.txt

@@ -30,7 +30,7 @@ foreach (test_name test_case IN ZIP_LISTS test_names test_cases)
         NAME ${test_name}
         WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
         COMMAND
-        ${CMAKE_COMMAND} -E env CPS_PATH=${CMAKE_CURRENT_SOURCE_DIR}/cps-files
+        ${CMAKE_COMMAND} -E env CPS_PREFIX_PATH=${CMAKE_CURRENT_SOURCE_DIR}/cps-files
         ${Python_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/runner.py
         $<TARGET_FILE:cps-config> ${test_case}
     )