interceptor: tidy up default_make_relative

This removes some outstanding code smells identified in aosp/1898997.
Some correctness fixes, some cleanups.

Bug: 207620569
Signed-off-by: Matthias Maennich <maennich@google.com>
Change-Id: Ic31b2ac1ef18b2a93b99dc2e303f7c6ccd66d1d6

1 files changed, 9 insertions, 23 deletions

diff --git a/interceptor.cc b/interceptor.cc
index 728161c..1f9f93d 100644
--- a/interceptor.cc
+++ b/interceptor.cc
@@ -126,28 +126,23 @@ static std::optional<std::string> command_getenv(const Command& command, const c
 
 static bool default_make_relative(Command* command) {
   // determine the ROOT_DIR
-  std::string root_directory;
+  fs::path root_directory;
   if (const auto root = command_getenv(*command, kEnvRootDirectory)) {
-    root_directory = *root;
-    if (root_directory[root_directory.size() - 1] != '/') {
-      root_directory += '/';
-    }
+    root_directory = fs::path(*root) / "";
   } else {
+    // there is no ROOT_DIR that we can use to make calls relative
     return false;
   }
 
   // determine the relative path to ROOT_DIR from the current working dir
-  std::string relative_root = fs::relative(root_directory);
-  if (relative_root[relative_root.size() - 1] != '/') {
-    relative_root += '/';
-  }
+  auto relative_root = fs::relative(root_directory) / "";
   if (relative_root == "./") {
     relative_root.clear();
   }
 
   // TODO: This is generally bad as this means we can't make anything relative.
   // This happens if the out dir is outside of the root.
-  if (relative_root.find(root_directory) != std::string::npos) {
+  if (relative_root.native().find(root_directory) != std::string::npos) {
     return false;
   }
 
@@ -155,9 +150,11 @@ static bool default_make_relative(Command* command) {
 
   // replacement functor
   const auto replace_all = [&](auto& str) {
+    size_t start = 0;
     auto pos = std::string::npos;
-    while ((pos = str.find(root_directory)) != std::string::npos) {
-      str.replace(pos, root_directory.length(), relative_root);
+    while ((pos = str.find(root_directory, start)) != std::string::npos) {
+      str.replace(pos, root_directory.native().length(), relative_root);
+      start = pos + relative_root.native().length();
     }
   };
 
@@ -189,17 +186,6 @@ class Analyzer {
 void Analyzer::set_inputs_outputs(Command* command) const {
   auto [inputs, outputs] = determine_inputs_outputs(*command);
 
-  // TODO: this sanitizing should be done during make_relative
-  for (auto& input : inputs) {
-    if (input.rfind("./", 0) == 0) {
-      input = input.substr(2);
-    }
-  }
-  for (auto& output : outputs) {
-    if (output.rfind("./", 0) == 0) {
-      output = output.substr(2);
-    }
-  }
   *command->mutable_inputs() = {inputs.begin(), inputs.end()};
   *command->mutable_outputs() = {outputs.begin(), outputs.end()};