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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_PRINTER_H
     18 #define ANDROID_PRINTER_H
     19 
     20 #include <android/log.h>
     21 
     22 namespace android {
     23 
     24 // Interface for printing to an arbitrary data stream
     25 class Printer {
     26 public:
     27     // Print a new line specified by 'string'. \n is appended automatically.
     28     // -- Assumes that the string has no new line in it.
     29     virtual void printLine(const char* string = "") = 0;
     30 
     31     // Print a new line specified by the format string. \n is appended automatically.
     32     // -- Assumes that the resulting string has no new line in it.
     33     virtual void printFormatLine(const char* format, ...) __attribute__((format (printf, 2, 3)));
     34 
     35 protected:
     36     Printer();
     37     virtual ~Printer();
     38 }; // class Printer
     39 
     40 // Print to logcat
     41 class LogPrinter : public Printer {
     42 public:
     43     // Create a printer using the specified logcat and log priority
     44     // - Unless ignoreBlankLines is false, print blank lines to logcat
     45     // (Note that the default ALOG behavior is to ignore blank lines)
     46     LogPrinter(const char* logtag,
     47                android_LogPriority priority = ANDROID_LOG_DEBUG,
     48                const char* prefix = 0,
     49                bool ignoreBlankLines = false);
     50 
     51     // Print the specified line to logcat. No \n at the end is necessary.
     52     virtual void printLine(const char* string);
     53 
     54 private:
     55     void printRaw(const char* string);
     56 
     57     const char* mLogTag;
     58     android_LogPriority mPriority;
     59     const char* mPrefix;
     60     bool mIgnoreBlankLines;
     61 }; // class LogPrinter
     62 
     63 // Print to a file descriptor
     64 class FdPrinter : public Printer {
     65 public:
     66     // Create a printer using the specified file descriptor.
     67     // - Each line will be prefixed with 'indent' number of blank spaces.
     68     // - In addition, each line will be prefixed with the 'prefix' string.
     69     FdPrinter(int fd, unsigned int indent = 0, const char* prefix = 0);
     70 
     71     // Print the specified line to the file descriptor. \n is appended automatically.
     72     virtual void printLine(const char* string);
     73 
     74 private:
     75     enum {
     76         MAX_FORMAT_STRING = 20,
     77     };
     78 
     79     int mFd;
     80     unsigned int mIndent;
     81     const char* mPrefix;
     82     char mFormatString[MAX_FORMAT_STRING];
     83 }; // class FdPrinter
     84 
     85 class String8;
     86 
     87 // Print to a String8
     88 class String8Printer : public Printer {
     89 public:
     90     // Create a printer using the specified String8 as the target.
     91     // - In addition, each line will be prefixed with the 'prefix' string.
     92     // - target's memory lifetime must be a superset of this String8Printer.
     93     String8Printer(String8* target, const char* prefix = 0);
     94 
     95     // Append the specified line to the String8. \n is appended automatically.
     96     virtual void printLine(const char* string);
     97 
     98 private:
     99     String8* mTarget;
    100     const char* mPrefix;
    101 }; // class String8Printer
    102 
    103 // Print to an existing Printer by adding a prefix to each line
    104 class PrefixPrinter : public Printer {
    105 public:
    106     // Create a printer using the specified printer as the target.
    107     PrefixPrinter(Printer& printer, const char* prefix);
    108 
    109     // Print the line (prefixed with prefix) using the printer.
    110     virtual void printLine(const char* string);
    111 
    112 private:
    113     Printer& mPrinter;
    114     const char* mPrefix;
    115 };
    116 
    117 }; // namespace android
    118 
    119 #endif // ANDROID_PRINTER_H
    120