compiler: @VMODULE

vlib/compiler/v_mod_cache.v

@@ -0,0 +1,153 @@
+module compiler
+
+import os
+import filepath
+
+
+// This file provides a caching mechanism for seeking quickly whether a
+// given folder has a v.mod file in it or in any of its parent folders.
+//
+// ModFileCacher.get(folder) works in such a way, that given this tree:
+// examples/hanoi.v
+// vlib/v.mod
+// vlib/compiler/tests/project_with_c_code/mod1/v.mod
+// vlib/compiler/tests/project_with_c_code/mod1/wrapper.v
+// -----------------
+// ModFileCacher.get('examples')
+// => ModFileAndFolder{'', 'examples'}
+// ModFileCacher.get('vlib/compiler/tests')
+// => ModFileAndFolder{'vlib/v.mod', 'vlib'}
+// ModFileCacher.get('vlib/compiler')
+// => ModFileAndFolder{'vlib/v.mod', 'vlib'}
+// ModFileCacher.get('vlib/project_with_c_code/mod1')
+// => ModFileAndFolder{'vlib/project_with_c_code/mod1/v.mod', 'vlib/project_with_c_code/mod1'}
+
+
+struct ModFileAndFolder {
+	// vmod_file contains the full path of the found 'v.mod' file, or ''
+	// if no 'v.mod' file was found in file_path_dir, or in its parent folders.
+	vmod_file string
+
+	// vmod_folder contains the file_path_dir, if there is no 'v.mod' file in
+	// *any* of the parent folders, otherwise it is the first parent folder,
+	// where a v.mod file was found.
+	vmod_folder string
+}
+
+struct ModFileCacher {
+mut:
+	cache map[string]ModFileAndFolder
+	// folder_files caches os.ls(key)
+	folder_files map[string][]string
+}
+
+fn new_mod_file_cacher() &ModFileCacher {
+	return &ModFileCacher{}
+}
+
+fn (mcache &ModFileCacher) dump() {
+	$if debug {
+		eprintln('ModFileCacher DUMP:')
+		eprintln('	 ModFileCacher.cache:')
+		for k,v in mcache.cache {
+			eprintln('	 K: ${k:-32s} | V: "${v.vmod_file:32s}" | "${v.vmod_folder:32s}" ')
+		}
+		eprintln('	 ModFileCacher.folder_files:')
+		for k,v in mcache.folder_files {
+			eprintln('	 K: ${k:-32s} | V: ${v.str()}')
+		}
+	}
+}
+
+fn (mcache mut ModFileCacher) get(mfolder string) ModFileAndFolder {
+	if mfolder in mcache.cache {
+		return mcache.cache[ mfolder ]
+	}
+	traversed_folders, res := mcache.traverse( mfolder )
+	for tfolder in traversed_folders {
+		mcache.add( tfolder, res )
+	}
+	return res
+}
+
+fn (cacher mut ModFileCacher) add(path string, result ModFileAndFolder) {
+	cacher.cache[ path ] = result
+}
+
+fn (mcache mut ModFileCacher) traverse(mfolder string) ([]string, ModFileAndFolder) {
+	mut cfolder := mfolder
+	mut folders_so_far := [cfolder]
+	mut levels := 0
+	for {
+		$if debug {
+			eprintln('pdir2vmod mfolder: ${mfolder:-32s} | cfolder: ${cfolder:-20s} | levels: $levels')
+		}
+		if levels > 255 {
+			break
+		}
+		if cfolder == '/' || cfolder == '' {
+			break
+		}
+		if cfolder in mcache.cache {
+			res := mcache.cache[ cfolder ]
+			if res.vmod_file.len == 0 {
+				mcache.mark_folders_as_vmod_free( folders_so_far )
+			}else{
+				mcache.mark_folders_with_vmod( folders_so_far, res )
+			}
+			return []string, res
+		}
+		files := mcache.get_files( cfolder )
+		if 'v.mod' in files {
+			// TODO: actually read the v.mod file and parse its contents to see
+			// if its source folder is different
+			res := ModFileAndFolder{ vmod_file: filepath.join( cfolder, 'v.mod'), vmod_folder: cfolder }
+			$if debug {
+				eprintln('FOUND v.mod:')
+				eprintln(' ModFileAndFolder{ vmod_file: $res.vmod_file , vmod_folder: $res.vmod_folder } ')
+			}
+			return folders_so_far, res
+		}
+		if mcache.check_for_stop( cfolder, files ) {
+			break
+		}
+		cfolder = filepath.basedir( cfolder )
+		folders_so_far << cfolder
+		levels++
+	}
+	mcache.mark_folders_as_vmod_free( folders_so_far )
+	return [mfolder], ModFileAndFolder{ vmod_file: '', vmod_folder: mfolder }
+}
+
+fn (mcache mut ModFileCacher) mark_folders_with_vmod( folders_so_far []string, vmod ModFileAndFolder ) {
+	for f in folders_so_far {
+		mcache.add( f, vmod )
+	}
+}
+
+fn (mcache mut ModFileCacher) mark_folders_as_vmod_free( folders_so_far []string ) {
+	// No need to check these folders anymore,
+	// because their parents do not contain v.mod files
+	for f in folders_so_far {
+		mcache.add( f, ModFileAndFolder{ vmod_file: '', vmod_folder: f } )
+	}
+}
+
+const ( MOD_FILE_STOP_PATHS = ['.git', '.hg', '.svn', '.v.mod.stop' ] )
+fn (mcache &ModFileCacher) check_for_stop(cfolder string, files []string) bool {
+	for i in MOD_FILE_STOP_PATHS {
+		if i in files {
+			return true
+		}
+	}
+	return false
+}
+
+fn (mcache mut ModFileCacher) get_files(cfolder string) []string {
+	if cfolder in mcache.folder_files {
+		return mcache.folder_files[ cfolder ]
+	}
+	files := os.ls(cfolder) or { return [] }
+	mcache.folder_files[ cfolder ] = files
+	return files
+}