From cce63aca270c51fb3ce9790438e3c23864de0a87 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Wed, 23 Dec 2015 21:43:51 +0100
Subject: Implement file change tracking using `diff`

The newly introduced `ChangeTracker` class is now keeping track of all tracked file in addition to spawning and managing a corresponding `diff` instance that enables printing pretty _patch-style_ change summaries to the logging target.

This commit introduces `boost-process` and `diff` as dependencies of this library.
---
 src/change_log.cc | 36 ++++++++++++------------------------
 1 file changed, 12 insertions(+), 24 deletions(-)

(limited to 'src/change_log.cc')

diff --git a/src/change_log.cc b/src/change_log.cc
index a9e485f..e128383 100644
--- a/src/change_log.cc
+++ b/src/change_log.cc
@@ -4,20 +4,18 @@
 
 #include <algorithm>
 #include <functional>
-#include <unordered_set>
 
 #include "io.h"
 #include "utility.h"
 #include "actual_function.h"
+#include "change_tracker.h"
 
-static std::unique_ptr<std::unordered_set<std::string>> tracked_files;
-static std::unique_ptr<io::FileDescriptorGuard>         fd_guard;
-static std::unique_ptr<utility::Logger>                 logger;
+static std::unique_ptr<io::FileDescriptorGuard> fd_guard;
+static std::unique_ptr<utility::Logger>         logger;
+static std::unique_ptr<utility::ChangeTracker>  tracker;
 
 void init() __attribute__ ((constructor));
 void init() {
-	tracked_files = std::make_unique<std::unordered_set<std::string>>();
-
 	if ( getenv("CHANGE_LOG_TARGET") != NULL ) {
 		fd_guard = std::make_unique<io::FileDescriptorGuard>(
 			getenv("CHANGE_LOG_TARGET")
@@ -26,6 +24,8 @@ void init() {
 	} else {
 		logger   = std::make_unique<utility::Logger>(STDERR_FILENO);
 	}
+
+	tracker = std::make_unique<utility::ChangeTracker>(logger.get());
 }
 
 void exit(int status) {
@@ -39,22 +39,12 @@ void exit(int status) {
 	actual_exit(status);
 }
 
-bool is_tracked_file(const std::string& file_name) {
-	return tracked_files->find(file_name) != tracked_files->end();
-}
-
-bool track_file(const std::string& file_name) {
-	return tracked_files->emplace(file_name).second;
-}
-
 ssize_t write(int fd, const void* buffer, size_t count) {
 	if ( io::is_regular_file(fd) ) {
 		const std::string file_name{ io::get_file_name(fd) };
 
-		if ( !is_tracked_file(file_name) ) {
-			track_file(file_name);
-
-			logger->append("wrote to '" + file_name + "'");
+		if ( !tracker->is_tracked(file_name) ) {
+			tracker->track(file_name);
 		}
 	}
 
@@ -62,8 +52,8 @@ ssize_t write(int fd, const void* buffer, size_t count) {
 }
 
 int rename(const char* old_path, const char* new_path) {
-	if ( !is_tracked_file(old_path) ) {
-		track_file(old_path);
+	if ( !tracker->is_tracked(old_path) ) {
+		tracker->track(old_path);
 	}
 
 	logger->append("renamed '" + std::string(old_path) + "' to '" + std::string(new_path) + "'");
@@ -99,10 +89,8 @@ void* mmap(void* addr, size_t length, int prot, int flags, int fd, off_t offset)
 	if ( ( prot & PROT_WRITE ) && io::is_regular_file(fd) ) {
 		const std::string file_name{ io::get_file_name(fd) };
 
-		if ( !is_tracked_file(file_name) ) {
-			track_file(file_name);
-
-			logger->append("mmap '" + file_name + "'");
+		if ( !tracker->is_tracked(file_name) ) {
+			tracker->track(file_name);
 		}
 	}
 
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