From e0d779a3106157a9bc83aa97e9d9fb1289dbdcbe Mon Sep 17 00:00:00 2001
From: Tobias Hunger <tobias.hunger@nokia.com>
Date: Tue, 15 Feb 2011 15:32:20 +0100
Subject: [PATCH] Env: Add method to get the difference between two Envs

Add a method returning the difference between two Environments.

Reviewed-by: dt
---
 src/libs/utils/environment.cpp | 32 ++++++++++++++++++++++++++++++++
 src/libs/utils/environment.h   |  2 ++
 2 files changed, 34 insertions(+)

diff --git a/src/libs/utils/environment.cpp b/src/libs/utils/environment.cpp
index 02827296a52..dffe886fcdd 100644
--- a/src/libs/utils/environment.cpp
+++ b/src/libs/utils/environment.cpp
@@ -321,6 +321,38 @@ void Environment::modify(const QList<EnvironmentItem> & list)
     *this = resultEnvironment;
 }
 
+QList<EnvironmentItem> Environment::diff(const Environment &other) const
+{
+    QMap<QString, QString>::const_iterator thisIt = constBegin();
+    QMap<QString, QString>::const_iterator otherIt = other.constBegin();
+
+    QList<EnvironmentItem> result;
+    while (thisIt != constEnd() || otherIt != other.constEnd()) {
+        if (thisIt == constEnd()) {
+            result.append(Utils::EnvironmentItem(otherIt.key(), otherIt.value()));
+            ++otherIt;
+        } else if (otherIt == constEnd()) {
+            Utils::EnvironmentItem item(thisIt.key(), QString());
+            item.unset = true;
+            result.append(item);
+            ++thisIt;
+        } else if (thisIt.key() < otherIt.key()) {
+            Utils::EnvironmentItem item(thisIt.key(), QString());
+            item.unset = true;
+            result.append(item);
+            ++thisIt;
+        } else if (thisIt.key() > otherIt.key()) {
+            result.append(Utils::EnvironmentItem(otherIt.key(), otherIt.value()));
+            ++otherIt;
+        } else {
+            result.append(Utils::EnvironmentItem(otherIt.key(), otherIt.value()));
+            ++otherIt;
+            ++thisIt;
+        }
+    }
+    return result;
+}
+
 bool Environment::hasKey(const QString &key)
 {
     return m_values.contains(key);
diff --git a/src/libs/utils/environment.h b/src/libs/utils/environment.h
index 0144d76993c..e946990c4ac 100644
--- a/src/libs/utils/environment.h
+++ b/src/libs/utils/environment.h
@@ -76,6 +76,8 @@ public:
     void set(const QString &key, const QString &value);
     void unset(const QString &key);
     void modify(const QList<EnvironmentItem> & list);
+    /// Return the Environment changes necessary to modify this into the other environment.
+    QList<EnvironmentItem> diff(const Environment &other) const;
     bool hasKey(const QString &key);
 
     void appendOrSet(const QString &key, const QString &value, const QString &sep = QString());