Svn 简明教程
SVN - Branching
分支操作创建另一条开发线。当有人希望开发过程分支到两个不同的方向时，它非常有用。假设你发布了 1.0 版本的产品，你可能希望创建一个新分支，以便 2.0 的开发可以与 1.0 的错误修复分开进行。
Branch operation creates another line of development. It is useful when someone wants the development process to fork off into two different directions. Let us suppose you have released a product of version 1.0, you might want to create new branch so that development of 2.0 can be kept separate from 1.0 bug fixes.
在本节中，我们将看到如何创建、遍历和合并分支。Jerry 对冲突不满意，因此他决定创建一个新的私有分支。
In this section, we will see how to create, traverse and merge branch. Jerry is not happy because of the conflict, so he decides to create a new private branch.
[jerry@CentOS project_repo]$ ls
branches tags trunk
[jerry@CentOS project_repo]$ svn copy trunk branches/jerry_branch
A branches/jerry_branch
[jerry@CentOS project_repo]$ svn status
A + branches/jerry_branch
[jerry@CentOS project_repo]$ svn commit -m "Jerry's private branch"
Adding branches/jerry_branch
Adding branches/jerry_branch/README
Committed revision 9.
[jerry@CentOS project_repo]$现在，Jerry 正在他的私有分支中工作。他为数组添加了排序操作。Jerry 修改后的代码看起来像这样。
Now Jerry is working in his private branch. He adds sort operation for the array. Jerry’s modified code looks like this.
[jerry@CentOS project_repo]$ cd branches/jerry_branch/
[jerry@CentOS jerry_branch]$ cat array.c上述命令将产生以下结果。
The above command will produce the following result.
#include <stdio.h>
#define MAX 16
void bubble_sort(int *arr, int n)
{
int i, j, temp, flag = 1;
for (i = 1; i < n && flag == 1; ++i) {
flag = 0;
for (j = 0; j < n - i; ++j) {
if (arr[j] > arr[j + 1]) {
flag = 1;
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
void accept_input(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
scanf("%d", &arr[i]);
}
void display(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
printf("|%d| ", arr[i]);
printf("\n");
}
int main(void)
{
int i, n, key, ret, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
/* Error handling for array overflow */
if (n >MAX) {
fprintf(stderr, "Number of elements must be less than %d\n", MAX);
return 1;
}
printf("Enter the elements\n");
accept_input(arr, n);
printf("Array has following elements\n");
display(arr, n);
printf("Sorted data is\n");
bubble_sort(arr, n);
display(arr, n);
return 0;
}Jerry 编译并测试他的代码，并准备提交他的更改。
Jerry compiles and tests his code and is ready to commit his changes.
[jerry@CentOS jerry_branch]$ make array
cc array.c -o array
[jerry@CentOS jerry_branch]$ ./array上述命令将产生以下结果。
The above command will produce the following result.
Enter the total number of elements: 5
Enter the elements
10
-4
2
7
9
Array has following elements
|10| |-4| |2| |7| |9|
Sorted data is
|-4| |2| |7| |9| |10|
[jerry@CentOS jerry_branch]$ svn status
? array
M array.c
[jerry@CentOS jerry_branch]$ svn commit -m "Added sort operation"
Sending jerry_branch/array.c
Transmitting file data .
Committed revision 10.同时，在主干上，Tom 决定实现搜索操作。Tom 添加了搜索操作的代码，他的代码看起来像这样。
Meanwhile, over in the trunk, Tom decides to implement search operation. Tom adds code for search operation and his code looks like this.
[tom@CentOS trunk]$ svn diff上述命令将产生以下结果。
The above command will produce the following result.
Index: array.c
===================================================================
--- array.c (revision 10)
+++ array.c (working copy)
@@ -2,6 +2,27 @@
#define MAX 16
+int bin_search(int *arr, int n, int key)
+{
+ int low, high, mid;
+
+ low = 0;
+ high = n - 1;
+ mid = low + (high - low) / 2;
+
+ while (low <= high) {
+ if (arr[mid] == key)
+ return mid;
+ if (arr[mid] > key)
+ high = mid - 1;
+ else
+ low = mid + 1;
+ mid = low + (high - low) / 2;
+ }
+
+ return -1;
+}
+
void accept_input(int *arr, int n)
{
int i;
@@ -22,7 +43,7 @@
int main(void)
{
- int i, n, arr[MAX];
+ int i, n, ret, key, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
@@ -39,5 +60,16 @@
printf("Array has following elements\n");
display(arr, n);
+ printf("Enter the element to be searched: ");
+ scanf("%d", &key);
+
+ ret = bin_search(arr, n, key);
+ if (ret < 0) {
+ fprintf(stderr, "%d element not present in array\n", key);
+ return 1;
+ }
+
+ printf("%d element found at location %d\n", key, ret + 1);
+
return 0;
}审阅后，他提交了自己的更改。
After reviewing, he commits his changes.
[tom@CentOS trunk]$ svn status
? array
M array.c
[tom@CentOS trunk]$ svn commit -m "Added search operation"
Sending trunk/array.c
Transmitting file data .
Committed revision 11.但 Tom 好奇 Jerry 在他的私有分支中做了什么。
But Tom is curious about what Jerry has been doing in his private branch.
[tom@CentOS trunk]$ cd ../branches/
[tom@CentOS branches]$ svn up
A jerry_branch
A jerry_branch/array.c
A jerry_branch/README
[tom@CentOS branches]$ svn log
------------------------------------------------------------------------
r9 | jerry | 2013-08-27 21:56:51 +0530 (Tue, 27 Aug 2013) | 1 line
Added sort operation
------------------------------------------------------------------------通过查看 Subversion 的日志消息，Tom 发现 Jerry 实现了“排序”操作。Tom 使用二分查找算法实现了搜索操作，它总是期望数据按已排序顺序显示。但如果用户提供未排序顺序的数据会怎样？在这种情况下，二分查找操作将会失败。因此，他决定在搜索操作之前使用 Jerry 的代码对数据进行排序。因此，他要求 Subversion 将代码从 Jerry 的分支合并到主干中。
By viewing the Subversion’s log message, Tom found that Jerry implemented 'sort' operation. Tom implemented search operation using binary search algorithm, it always expects data in sorted order. But what if the user provides data in an unsorted order? In that situation, binary search operation will fail. So he decides to take Jerry’s code to sort data before search operation. So he asks Subversion to merge code from Jerry’s branch into trunk.
[tom@CentOS trunk]$ pwd
/home/tom/project_repo/trunk
[tom@CentOS trunk]$ svn merge ../branches/jerry_branch/
--- Merging r9 through r11 into '.':
U array.c合并后，array.c 将看起来像这样。
After merging, array.c will look like this.
[tom@CentOS trunk]$ cat array.c上述命令将产生以下结果。
The above command will produce the following result.
#include <stdio.h>
#define MAX 16
void bubble_sort(int *arr, int n)
{
int i, j, temp, flag = 1;
for (i = 1; i < n && flag == 1; ++i) {
flag = 0;
for (j = 0; j < n - i; ++j) {
if (arr[j] > arr[j + 1]) {
flag = 1;
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
int bin_search(int *arr, int n, int key)
{
int low, high, mid;
low = 0;
high = n - 1;
mid = low + (high - low) / 2;
while (low <= high) {
if (arr[mid] == key)
return mid;
if (arr[mid] > key)
high = mid - 1;
else
low = mid + 1;
mid = low + (high - low) / 2;
}
return -1;
}
void accept_input(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
scanf("%d", &arr[i]);
}
void display(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
printf("|%d| ", arr[i]);
printf("\n");
}
int main(void)
{
int i, n, ret, key, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
/* Error handling for array overflow */
if (n > MAX) {
fprintf(stderr, "Number of elements must be less than %d\n", MAX);
return 1;
}
printf("Enter the elements\n");
accept_input(arr, n);
printf("Array has following elements\n");
display(arr, n);
printf("Sorted data is\n");
bubble_sort(arr, n);
display(arr, n);
printf("Enter the element to be searched: ");
scanf("%d", &key);
ret = bin_search(arr, n, key);
if (ret < 0) {
fprintf(stderr, "%d element not present in array\n", key);
return 1;
}
printf("%d element found at location %d\n", key, ret + 1);
return 0;
}在编译和测试后，Tom 将更改提交到存储库。
After compilation and testing, Tom commits his changes to the repository.
[tom@CentOS trunk]$ make array
cc array.c -o array
[tom@CentOS trunk]$ ./array
Enter the total number of elements: 5
Enter the elements
10
-2
8
15
3
Array has following elements
|10| |-2| |8| |15| |3|
Sorted data is
|-2| |3| |8| |10| |15|
Enter the element to be searched: -2
-2 element found at location 1
[tom@CentOS trunk]$ svn commit -m "Merge changes from Jerry's code"
Sending trunk
Sending trunk/array.c
Transmitting file data .
Committed revision 12.
[tom@CentOS trunk]$